Southern Cross University ePublications@SCU
Theses
2016 Conservation management and population recovery of East Australian Humpback Whales David Paton Southern Cross University
Publication details Paton, D 2016, 'Conservation management and population recovery of East Australian Humpback Whales', PhD thesis, Southern Cross University, Lismore, NSW. Copyright D Paton 2016
ePublications@SCU is an electronic repository administered by Southern Cross University Library. Its goal is to capture and preserve the intellectual output of Southern Cross University authors and researchers, and to increase visibility and impact through open access to researchers around the world. For further information please contact [email protected]. Conservation Management and Population Recovery of East Australian Humpback Whales
By David Paton, B.Ap.S.
School of Environmental Science and Management,
Southern Cross University, NSW, Australia
A thesis submitted for the degree of
Doctor of Philosophy
1 July, 2016
Migaloo, meaning “White Fella” in Aboriginal, is probably the best known whale within the east Australian humpback whale population. He was first sighted from Cape Byron in 1991. Since then he has been seen regularly at different locations along the east coast of Australia. In 2015 Migaloo was seen in Cook Strait, New Zealand.
Photo credit: Dave Paton
DECLARATION
I certify that the work presented in this thesis is, to the best of my knowledge and belief, original, except as acknowledged in the text, and that the material has not been submitted, either in whole or in part, for a degree at this or any other university.
I acknowledge that I have read and understood the University's rules, requirements, procedures and policy relating to my higher degree research award and to my thesis. I certify that I have complied with the rules, requirements, procedures and policy of the University (as they may be from time to time).
David Paton
1 July 2016
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ABSTRACT
Humpback whale (Megaptera novaeangliae) populations in the Southern Hemisphere (SH) were taken to the edge of extinction from over exploitation by whaling in the 19th and 20th centuries. Commercial whaling on SH humpback whales ended in 1963 (apart from illegal catches) and a moratorium on all commercial whaling was implemented in 1986. Since this time, many but not all, humpback whale populations in the SH have shown signs of recovery. The International Whaling Commission (IWC) is currently undertaking a review of the status of all SH humpback whale populations.
The aim of this thesis is to investigate the population status, structure and migratory interchange of Southern Hemisphere humpback whales (SHH) with a specific focus on east Australian humpback whales (EAH). This population has shown a strong recovery over the last 20 years. However, the migratory interchange and linkages among SHH populations, including EAH and neighbouring populations in Oceania, is not well understood. This uncertainty presents a potential challenge for the accurate assessment of stock structure and also makes it difficult to estimate pre-exploitation population size accurately and therefore determine the present status of their recovery.
This thesis documents the movement patterns of EAH based on existing and previously unpublished Discovery mark data. These data indicate that SHH form relatively discrete groups with strong linkages between tropical breeding grounds and specific Antarctic feeding areas. There is a relatively low incidence of large-scale movement between feeding areas, perhaps with the exception of Breeding Stock E (comprised of EAH, New Caledonia and Tonga breeding stocks), which appears to have a more broadly dispersed system of interchange between multiple breeding and feeding areas. These findings are consistent with those of similar recent studies using molecular and photo-identification techniques. It now appears that the dispersal of whales from Breeding Stock E is considerably wider than was originally considered to be their feeding area (between 130° E and 170° W), extending from 95° W to 87° E and covering a range of approximately 175° of longitude – nearly half the globe.
The IWC review involves an in-depth evaluation of the status of whale stocks. It includes the examination of issues such as current stock size, recent population trends, carrying capacity and productivity. This thesis provides valuable information on the recent
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population trend for EAH during their northward migration between 1998 and 2004. The annual rate of increase observed for humpback whales migrating past Cape Byron between 1998 and 2004 is calculated to be 11.0% (95% CI 2.3–20.5).
This research also derived two population estimates based on photo-identification capture recapture methods. The first estimate of 7,041 (95% CI: 4,075-10,008) is based on a multi- point single year (2005) population estimate using photo-identification data collected at Byron Bay, Hervey Bay and Ballina. The second estimate of 7,390 (95% CI: 4,040-10,739) is a multi-year population estimate for the population in 2005 using photo identification data collected at Byron Bay between 1999 and 2005. These are the first and only population estimates available for these sites. The results from this work are consistent with results for other survey areas on the east coast of Australia using different methodology. While the population estimates presented here utilise different assumptions and are potentially subject to different biases, the fact these studies obtained comparable results provides good confidence in the estimates.
Already data from this thesis have been applied for the purposes of conservation management. They were presented by the author to the IWC Comprehensive Assessment of Southern Hemisphere Humpback Whales (CASH) process and were a critical source of information in that process. Specifically, they were used to reduce the number of plausible stock structure hypotheses, to develop scenarios for the allocation of historic catch from feeding grounds to Breeding Stocks, and made a vital contribution to the identification of stock structure itself.
The thesis also reviews the management of EAH in Australia, their status under the Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act), and identifies further research required in order to address unresolved management and conservation questions. A review of the current status of the EAH population determined that they no longer meet the Threatened Species criteria under the EPBC Act and should be considered for delisting.
Overall, this thesis provides new insights into EAH population structure, status and management issues, and summarises an extensive body of work by the author with the support of a range of collaborators. This work will allow the IWC and Australian management authorities to better manage and conserve EAH into the future.
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ACKNOWLEDGEMENTS
The journey of completing this PhD has been a long one, undertaken part time over 12 years. However, the journey didn’t start 12 years ago, it began in 1986 when two good friends and work colleagues, Dean Lee and Mike Osmond, introduced me to humpback whale research while working with them as a Marine Park Ranger on the Great Barrier Reef.
Since then my whale research journey has taken me all over the world, from the tropics to the Antarctic. I have worked with a wide range of people, who have taken me under their wing and provided me with opportunities, guidance and direction. While it would be too difficult to mention all of them here, there are a number who deserve special thanks.
Guy Holloway provided opportunities and support for me to continue my interests in whale research when I took up a management position with NSW National Parks and Wildlife Service (NPWS) on the far north coast of NSW. Through the support provided by NSW NPWS and that of Peter Baverstock at Southern Cross University, I was able to establish the Cape Byron Whale Research Project (CBWRP) at Cape Byron in 1995. I coordinated the CBWRP between 1995 and 2005, and over that time had many people provide assistance and support for the project. Of particular importance was Dan Burns who assisted with the coordination of field work over a number of years and collaborated on a number of the papers in this thesis. Others who played a role in the CBWRP including Nick Rigby, Sue Walker, Bob Beal, and the rest of the staff and volunteers at Cape Byron; Megan Anderson, Adrian Oosterman, Merv Wicker, Paul Hodda, Max Egan, Peter Harrison, Ted Taylor, John Sugarman, Robyn McCulloch, Greg Luker, Wendy Stewart, Simon Walsh, Steve Booth, Andrew Nichols, Wave O’Connor, Hera Sengers, Wayne Pellow, Steve King, Greg Gorman, Ant Muyt and Chas Simpson. In addition I would like to recognise the huge number of students from Southern Cross University and other volunteers who assisted with the CBWRP over the ten years I coordinated the project.
Eric Kniest has been an untiring supporter and friend since 1998 when he became involved in the CBWRP. Eric is the ‘father’ of Cyclopes, which has now evolved into Vadar. Without his input into and development of this whale positioning and tracking software package, finding whales in the research boat and analysing the land-based data associated with the CBWRP would have been a total nightmare. Thank you Eric, I really appreciate your ongoing support and friendship. Eric also brought with him an abundant supply of good
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students from Newcastle University, whom I would like to acknowledge – in particular I’d like to thank Grant Baker. I have Greg Mann to thank for introducing me to Eric and for his ongoing support with whale research projects.
Also worthy of special mention are my collaborators. Without their assistance and willingness to work together, this thesis would not have been as successful. They include Dan Burns, Eric Kniest, Wally and Trish Franklin. Others that have assisted in this work in one way or another include Cherry Allison, Doug Cato, Rebecca Dunlop and Melinda Rekdahl.
I am grateful for the ongoing friendship and support of my colleagues in the South Pacific Whale Research Consortium. These people have opened my eyes in relation to the bigger picture of whale conservation and a whole new world through working in Oceania. I owe Phil Clapham a big thanks for his assistance with Discovery mark data and his advice and assistance with replicating Bill Dawbin’s work in Fiji.
I would like to make special mention of my supervisors, Peter Baverstock and Lyndon Brooks, who have guided me though the PhD process. While it has been a slow journey with lots of distractions, Bav and Lyndon have always been there to support me and keep me focused on finishing. While not formally supervisors, Simon Childerhouse and Mike Noad have also provided ongoing assistance, encouragement and support throughout my PhD. Simon, in particular, provided constructive feedback on my draft thesis. His comments helped me focus and develop further my critical thinking, which greatly improved my work. Also worthy of special mention is Lesley Douglas who has provided editorial assistance and proof reading of the final document. I need also to recognise the BPM team who have been supportive in me completing this work.
Most of all I need to recognise the ongoing support of my wife Sue and children, Tayla and Alyssa who have put up with me during this long journey. They have often played second fiddle to my passion (or is it obsession?) for whale research. Many a season has Sue called herself a ‘whale widow’. I really appreciate your patience, ongoing support and encouragement to finish this work.
Finally I would like to acknowledge my parents, Ian and Evelyn who have always encouraged me to push myself to get the most out of life. They have always been there to support me through all my different endeavours. While Dad isn’t here to see me finish my
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PhD, he was a big part of this journey and I would like to dedicate this work to his memory. Miss you Dad!
When I started working with whales, I never thought I could make a living out of it. Now it’s not only my passion, it is my work!
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LIST OF PUBLICATIONS
Listed below are two publications used as part of this thesis and for which David Paton was lead author. These publications appeared in the Journal of Cetacean Research and Management, which is a refereed scientific journal. A further two reports were accepted as papers to the Scientific Committee of the IWC and underwent peer review in that forum.
Paton DA, Kniest E (2011). Population growth of Australian East coast humpback whales, observed from Cape Byron, 1998 to 2004. Journal of Cetacean Research and Management (Special Issue) 3, 261–268.
Refer to Appendix I for a direct reprint of this paper from the Journal of Cetacean Research and Management.
Paton DA, Brooks L, Burns D, Franklin T, Franklin W, Harrison P, Baverstock P. (2011). Abundance of East coast Australian humpback whales (Megaptera novaeangliae) in 2005 estimated multi-point sampling and capture-recapture analysis. Journal of Cetacean Research and Management (Special Issue) 3, 253–259.
Refer to Appendix III for a direct reprint of this paper from the Journal of Cetacean Research and Management.
Paton DA, Brooks L, Burns D, Kniest E, Harrison P, Baverstock P. (2011). Abundance estimate of Australian east coast humpback whales (Group E1) in 2005 using multi- year photo-identification data and capture-recapture analysis. Paper SC/61/SH10 presented to the Scientific Committee of the IWC.
A previous version of this paper was presented at the IWC intercessional meeting in Hobart undertaking a Comprehensive Assessment of Southern Hemisphere Humpback Whales (CASH). While this paper was not formally published, it was discussed in detail at the IWC meeting and was used to explore and develop models of population structure.
Paton DA, Clapham P (2006). An assessment of Southern Hemisphere humpback whale population structure and migratory interchange based on Discovery mark data. Paper SC/A06/HW33 presented to the Scientific Committee of the IWC.
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A previous draft version of this paper was presented at the IWC intercessional meeting in Hobart undertaking a CASH. While this paper was not formally published, it was discussed in detail at the IWC meeting and was used to explore and develop models of population structure.
I warrant that I have obtained, where necessary, permission from the copyright owners to use any third-party copyright material reproduced in the thesis or to use any of my own published work in which the copyright is held by another party.
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LIST OF ADDITIONAL PUBLICATIONS
SCIENTIFIC PAPERS PUBLISHED IN PEER-REVIEWED JOURNALS
Burns D, Brooks L, Harrison P, Franklin T, Franklin W, Paton D (2014). Migratory movements of individual humpback whales photographed off the eastern coast of Australia 2003-2005. Marine Mammal Science. Marine Mammal Science 30(2): 562- 578.
Schmitt N, Double M, Baker S, Gales N, Childerhouse S, Polanowski A, Steel D, Albertson G, Olavarría C, Garrigue C, Poole M, Hauser N, Constantine R, Paton D, Jarman CS, Peakall R (2014). Mixed-stock analysis of humpback whales (Megaptera novaeangliae) on Antarctic feeding grounds. Journal of Cetacean Research and Management (14): 141-157.
Schmitt NT, Double MC, Jarman SN, Gales N, Marthick JR, Polanowski AM, Baker CS, Steel D, Jenner KCS, Jenner MN, Gales R, Paton D, Peakall R (2014). Australian humpback whale populations (Megaptera novaeangliae) display low differentiation, a characteristic of southern hemisphere populations. Marine Mammal Science 30(1): 221-241.
Constantine R, Steel D, Allen J, Anderson M, Andrews O, Baker CS, Beeman P, Burns D, Charrassin JB, Childerhouse S, Double M, Ensor P, Franklin T, Franklin W, Gales N, Garrigue C, Gibbs N, Harrison P, Hauser N, Hutsel A, Jenner C, Jenner MN, Kaufman G, Macie A, Mattila D, Olavarría C, Oosterman A, Paton D, Poole M, Robbins J, Schmitt N, Stevick P, Tagarino A, Thompson K, Ward J (2014). Remote Antarctic feeding ground important for east Australian humpback whales. Marine Biology DOI 10.1007/s00227-014-2401-2.
Schmitt NT, Double MC, Jarman SN, Gales N, Marthick JR, Polanowski A, Baker CS, Steel D, Jenner KCS, Jenner MN, Gales R, Paton D, Peakall R (2014). Low levels of genetic differentiation characterize Australian humpback whale (Megaptera novaeangliae) populations. Marine Mammal Science 30(1): 221-241.
Burns D, Brooks L, Harrison P, Franklin T, Franklin W, Paton D, Clapham P (2013). Migratory movements of individual humpback whales photographed off the eastern coast of Australia. Marine Mammal Science DOI: 10.1111/mms.12057.
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Franklin W, Franklin T, Brooks L, Gibbs N, Childerhouse S, Smith F, Burns D, Paton D, Garrigue C, Constantine R, Poole M, Hauser N, Donoghue M, Russell K, Mattila DK, Robbins J, Oosterman A, Leaper R, Harrison P, Baker CS, Clapham P (2012). Antarctic waters (Area V) near the Balleny Islands are a summer feeding area for some eastern Australian Breeding Stock E(i) humpback whales (Megaptera novaeangliae). Journal of Cetacean Research and Management 12(3): 321-327.
Polanowski A, Robinson-Laverick, S, Paton D, Jarman S (2012). Variation in the Tyrosinase Gene Associated with a White Humpback Whale (Megaptera novaeangliae). Journal of Heredity 103(1): 130-133.
Smith JN, Grantham HS, Gales N, Double MC, Noad MJ, Paton D (2012). Identification of humpback whale breeding and calving habitat in the Great Barrier Reef. Marine Ecology Progress Series 447: 259-272.
Garrigue C, Constantine R, Poole M, Hauser N, Clapham P, Donoghue M, Russell K, Paton D, Matilla DK, Robbins J, Baker CS (2011). Movement of individual humpback whales between wintering grounds of Oceania (South Pacific), 1999 to 2004. Journal of Cetacean Research and Management (Special Issue) 3: 275-281.
Garrigue C, Franklin T, Russell K, Burns D, Poole M, Paton D, Hauser N, Oremus M, Constantine R, Childerhouse S, Mattila DK, Franklin W, Robbins J, Clapham P, Baker CS (2011). First assessment of interchange of humpback whales between Oceania and the east coast of Australia. Journal of Cetacean Research and Management Special Issue 3: 269-274.
Noad MJ, Dunlop RA, Paton D, Cato DH (2011). Absolute and relative abundance estimates of Australian east coast humpback whales (Megaptera novaeangliae). Journal of Cetacean Research and Management Special Issue 3: 43-252.
Clapham P, Mikhalev Y, Franklin W, Paton D, Baker SC, Brownell R (2009). Catches of Humpback Whales by the Soviet Union and Other Nations in the Southern Ocean, 1947-1973. Marine Fisheries Review 71(1): 39-43.
Olavarría C, Baker CS, Garrigue C, Poole M, Hauser N, Caballero S, Flórez-González L, Brasseur M, Bannister J, Capella J, Clapham P, Dodemont R, Donoghue M, Jenner C, Jenner MN, Moro D, Oremus M, Paton D, Rosenbaum H, Russell K (2007). Population structure of humpback whales throughout the South Pacific and the origin
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of the eastern Polynesian breeding grounds. Marine Ecology Progress Series 330: 257- 268.
Forestell PH, Paton DA, Hodda P, Kaufman GD (2001). Observations of a hypo-pigmented humpback whale, Megaptera novaeangliae, off the east coast Australia, 1991-2000. Memoirs of the Queensland Museum 47(2): 437 – 450.
Anderson MJ, Hinten G, Paton D, Baverstock PR (2001). A model for the integration of micro satellite genotyping with photographic identification of humpback whales. Memoirs of the Queensland Museum 47(2): 451 – 458.
Kneist E, and Paton D (2001). Real Time Tracking of Humpback Whales. Memoirs of the Queensland Museum 47(2): 538.
SCIENTIFIC PAPERS IN PRESS / REVIEW / SUBMITTED
Franklin T, Smith F, Gibbs N, Childerhouse S, Burns D, Paton D, Franklin W, Baker CS, Clapham P (in press). Migratory movements of humpback whales (Megaptera novaeangliae) between eastern Australia and the Balleny Islands, Antarctica, confirmed by photo-identification. Journal of Cetacean Research and Management.
Franklin W, Franklin T, Gibbs N, Childerhouse S, Garrigue C, Constantine R, Brooks L, Burns D, Paton D, Poole M, Hauser N, Donoghue M, Russell K, Mattila D Robbins J, Anderson M, Olavarría C, Jackson J, Noad M, Harrison P, Baverstock P, Leaper R, Baker CS, Clapham P (in press). Eastern Australia (E1 breeding grounds) may be a wintering destination for some Area V Humpback Whales (Megaptera novaeangliae) migrating through New Zealand waters. Journal of Cetacean Research and Management.
Paton DA, Oosterman A, Whicker M, Kenny I, Christian M, Garrigue C (in review). Assessment of sighting survey data for humpback whales (Megaptera novaeangliae) at Norfolk Island 2003-2006 and a comparison with historical records for the region. Journal of Cetacean Research and Management.
Steel D, Garrigue C, Poole M, Hauser N, Olavarría C, Flórez-González R, Constantine R, Caballero S, Thiele D, Slooten L, Dawson S, Oremus M, Russell K, Paton D, Clapham P, Donoghue M, Baker CS (in review). Migratory connections between humpback
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whales from South Pacific breeding grounds and Antarctic feeding areas based on genotype matching. Marine Mammal Science.
Constantine R, Steel D, Allen J, Anderson M, Andrews O, Baker CS, Baverstock P, Beeman P, Burns D, Charrassin JB, Childerhouse S, Double M, Ensor P, Franklin T, Franklin W, Gales N, Garrigue C, Gates E, Gibbs N, Harrison P, Hauser N, Hutsel A, Jenner C, Jenner M, Kaufman G, Macie A, Mattila D, Olavarría C, Oosterman A, Paton D, Poole M, Robbins J, Schmitt N, Stevick P, Tagarino A, Thompson K, Ward J (submitted). East Australia Humpback Whale Feeding Ground Confirmed. Biology Letters.
PAPERS PRESENTED TO THE SCIENTIFIC COMMITTEE OF THE INTERNATIONAL WHALING COMMISSION
Jackson J, Anderson M, Steel D, Brooks L, Baverstock P, Burns D, Clapham P, Constantine R, Franklin W, Franklin T, Garrigue C, Hauser N, Paton D, Poole M, Baker CS (2012). Multistate measurements of genotype interchange between East Australia and Oceania (IWC breeding sub-stocks E1, E2, E3 and F2) between 1999 and 2004. Paper SC/64/SH22.
Constantine R, Allen J, Beeman P, Burns D, Charrassin JB, Childerhouse S, Double M, Ensor P, Franklin T, Franklin W, Gales N, Garrigue C, Gates E, Gibbs N, Hutsel A, Jenner C, Jenner M, Kaufman G, Macie A, Mattila D, Oosterman A, Paton D, Robbins J, Schmitt N, Stevick P, Tagarino A, Thompson K (2011). Comprehensive photo- identification matching of Antarctic Area V humpback whales. Paper SC/63/SH16.
Kaufman GD, Coughran D, Allen J, Burns D, Burton C, Castro C, Childerhouse S, Constantine R, Franklin T, Franklin W, Forestell P, Gales R, Garrigue C, Gibbs N, Jenner C, Paton D, Noad M, Robbins J, Slooten E, Smith F, Stevick P (2011). Photographic evidence of interchange between East Australia (BS E-1) and West Australia (BS-D) breeding populations. Paper SC/63/SH11.
Franklin T, Franklin W, Gibbs N, Childerhouse S, Garrigue C, Constantine R, Brooks L, Burns D, Paton D, Poole M, Hauser N, Donoghue M, Russell K, Mattila DK, Robbins J, Anderson M, Olavarría C, Jackson J, Noad M, Harrison P, Baverstock P, Leaper R, Baker CS, Clapham P (2011). Photo-identification confirms that humpback whales
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(Megaptera novaeangliae) from eastern Australia migrate past New Zealand but indicates low levels of interchange with breeding grounds of Oceania. Journal of Cetacean Research and Management: Paper SC/63/ ForInfo20.
Franklin T, Franklin W, Brooks L, Gibbs N, Childerhouse S, Smith F, Burns D, Paton D, Garrigue C, Constantine R, Poole MM, Hauser N, Donoghue M, Russell K, Mattila DK, Robbins J, Oosterman A, Leaper R, Harrison P, Baker CS, Clapham, P (2011). Antarctic waters (Area V) near the Balleny Islands are a summer feeding area for some Eastern Australian (E (i) breeding group) humpback whales (Megaptera novaeangliae). Journal of Cetacean Research and Management: Paper SC/63/ForInfo21.
Garrigue C, Constantine R, Poole M, Hauser N, Clapham P, Donoghue M, Russell K, Paton D, Mattila DK, Robbins J, Baker CS (2011). Movements of individual humpback whales between wintering grounds of Oceania (South Pacific), 1999 to 2004. Journal of Cetacean Research and Management: Special Issue on Southern Hemisphere Humpback Whales. Paper SC/63/ ForInfo34.
Garrigue C, Franklin T, Constantine R, Russell K, Burns D, Poole M, Paton D, Hauser N, Oremus M, Childerhouse S, Mattila DK, Gibbs N, Franklin W, Robbins J, Clapham P, Baker CS (2011). First assessment of interchange of humpback whales between Oceania and the east coast of Australia. Journal of Cetacean Research and Management: Special Issue on Southern Hemisphere Humpback Whales. Paper SC/63/ ForInfo35.
Noad M, Dunlop R, Paton D, Kniest E (2011). Abundance estimates of the east Australian humpback whale population: 2010 survey and update 12pp. Paper SC/63/SH22.
Steel D, Schmitt N, Anderson M, Burns D, Childerhouse S, Constantine R, Franklin T, Franklin W, Gales N, Garrigue C, Gibb N, Hauser N, Mattila D, Olavarría C, Paton D, Poole M, Robbins J, Ward J, Harrison P, Baverstock P, Double M, Baker CS (2011). Initial genotype matching of humpback whales from the 2010 Australia / New Zealand Antarctic Whale Expedition (Area V) to Australia and the South Pacific. Paper SC/63/SH10.
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Gales N, Double M, Robinson S, Jenner C, Jenner M, King E, Gedamke J, Childerhouse S, Paton D (2010). Satellite tracking of Australian humpback (Megaptera novaeangliae) and pygmy blue whales (Balaenoptera musculus brevicauda). Paper SC/62/SH21.
Anderson M, Steel D, Franklin W, Franklin T, Paton D, Burns D, Harrison P, Baverstock PR, Garrigue C, Olavarría C Poole M, Hauser N, Constantine R, Thiele D, Clapham P, Donoghue M, Baker CS (2010). Microsatellite genotype matches of eastern Australian humpback whales to Area V feeding and breeding grounds. Paper SC/62/SH7.
Gales N, Double MC, Robinson S, Jenner C, Jenner M, King E, Gedamke J, Paton D, Raymond B (2009). Satellite tracking of southbound East Australian humpback whales (Megaptera novaeangliae): challenging the feast or famine model of migrating whales. Paper SC/61/SH17.
Paton DA, Brooks L, Burns D, Kniest E, Harrison P, Baverstock P (2009). Abundance estimate of Australian east coast humpback whales (Breeding Stock EI) in 2005 using multi-year photo-identification data and capture-recapture analysis.
Franklin T, Franklin W, Brooks L, Gibbs N, Childerhouse S, Smith F, Burns D, Paton D, Garrigue C, Constantine R, Poole M, Hauser N, Donoghue M, Russell K, Mattila DK, Robbins J, Oosterman A, Leaper R, Baker S, Clapham, P (2008). Migratory movements of humpback whales (Megaptera novaeangliae) between eastern Australia and the Balleny Islands, Antarctica, confirmed by photo-identification. Paper SC/60/SH2.
Franklin W, Franklin T, Brooks L, Gibbs N, Childerhouse S, Burns D, Paton D, Garrigue C, Constantine R, Poole M, Hauser N, Donoghue M, Russell K, Mattila DK, Robbins J, Anderson M, Olavarría C, Jackson J, Noad M, Harrison P, Baverstock P, Leaper R, Baker S, Clapham, P (2008). Eastern Australia (E1 breeding grounds) may be a wintering destination for Area V humpback whales (Megaptera novaeangliae) migrating through New Zealand waters. Paper SC/60/SH3.
Noad MJ, Dunlop RA, Paton D, Cato DH (2008). An update of the east Australian humpback whale population (E1) rate of increase. 13pp. Paper SC/60/SH31.
Steel D, Garrigue C, Poole M, Hauser N, Olavarría C, Florez-Gonzalez L, Constantine R, Caballero S, Thiele D, Paton D, Clapham P, Donoghue M, Baker CS (2008).
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Migratory connections between humpback whales from South Pacific breeding grounds and Antarctic feeding areas based on genotype matching. Paper SC/60/SH13.
Garrigue C, Franklin T, Russell K, Burns D, Poole M, Paton D, Hauser N, Oremus M, Constantine R, Childerhouse S, Mattila D, Gibbs N, Franklin W, Robbins J, Clapham P, Baker CS (2007). First assessment of interchange of humpback whales between Oceania and the east coast of Australia. South Pacific Whale Research Consortium. Paper SC/59/SH15.
Garrigue C, Baker CS, Constantine R, Poole M, Hauser N, Clapham P, Donoghue M, Russell K, Paton D, Mattila D and Robbins J (2007). Interchange of humpback whales in Oceania (South Pacific), 1999 to 2004 (revised SC/A06/HW55, March 2007). Paper SC/59/HW14.
Franklin T, Smith F, Gibbs N, Childerhouse S, Burns D, Paton D, Franklin W, Baker CS, Clapham P (2007). Migratory movements of humpback whales (Megaptera novaeangliae) between eastern Australia and the Balleny Islands, Antarctica, confirmed by photo-identification. Paper SC/59/SH18.
Ivashchenko YV, Clapham P, Doroshenko NV, Paton DA, Brownell RL (2007). Possible Soviet catches of humpback whales in Fiji and Tonga. Paper to the IWC Scientific Committee.
Franklin T, Smith F, Gibbs N, Childerhouse S, Burns D, Paton D, Franklin W, Baker CS, Clapham P (2007). Migratory movements of humpback whales (Megaptera novaeangliae) between eastern Australia and the Balleny Islands, Antarctica, confirmed by photo-identification. Paper SC/59/SH18.
Olavarría C, Anderson M, Paton D, Burns D, Brasseur M, Garrigue C, Hauser N, Poole M, Caballero S, Florez-Gonzalez L, Baker CS (2006). Eastern Australia humpback whale genetic diversity and their relationship with Breeding Stocks D, E, F and G. Paper SC/58/SH25.
Noad M, Paton D, Cato DH (2006). Absolute and relative abundance estimates of Australian east coast humpback whales. Paper SC/A06/HW27.
Noad M, Paton DA, Gibbs NJ, Childerhouse SJ (2006). A combined visual and acoustic survey of the cetaceans of Independent Samoa. Paper SC/A06/HW28.
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Paton D, Brooks L, Burns D, Franklin T, Franklin W, Harrison P, Baverstock P (2006) First abundance estimate of East Coast Australian humpback whales (Megaptera novaeangliae) utilising multi-point sampling and likelihood analysis. Paper SC/A06/HW32.
Gibbs N, Paton D, Childerhouse S, Clapham P (2006). Assessment of the current abundance of humpback whales in the Lomaiviti Island Group of Fiji and a comparison with historical data. Paper SC/A06/HW34.
Paton D, Kniest E (2006). Analysis of data collected during humpback whale land based sighting surveys at Cape Byron, Eastern Australia, 1998 to 2004. Paper SC/A06/HW35.
Paton D, Oosterman A, Whicker M, Kenny I (2006). Preliminary assessment of sighting survey data of humpback whales, Norfolk Island, Australia. Paper SC/A06/HW36.
Baker CS, Garrigue C, Constantine R, Madon B, Poole M, Hauser N, Clapham P, Donoghue M, Russell K, Paton D, Mattila D (2006). Abundance of humpback whales in Oceania (South Pacific), 1999 to 2004. Paper SC/A06/HW51.
Garrigue C, Baker CS, Constantine R, Poole M, Hauser N, Clapham P, Donoghue M, Russell K, Paton D, Mattila D (2006). Interchange of humpback whales in Oceania (South Pacific), 1999 to 2004. Paper SC/A06/HW55.
Paton D A, Clapham P J (2006). An assessment of Southern Hemisphere humpback whale population structure and migratory interchange based on Discovery mark data. Paper SC/A06/HW33.
Olavarría C, Baker C S, Garrigue C, Poole M, Hauser N, Caballero S, Flórez-González L, Brasseur M, Bannister J, Capella J, Clapham P, Dodemont R, Donoghue M, Jenner C, Jenner MN, Moro D, Oremus M, Paton D, Russell K (2005). Population structure of humpback whales throughout the South Pacific with reference to the origins of the eastern Polynesian breeding grounds. Paper SC/57/For Info.
Clapham P, Mikhalev YU, Franklin W, Paton D, Baker CS, Brownell RL (2004). Catches of humpback whales in the Southern Ocean, 1947-1973. Paper SC/57/SH6.
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Olavarría C, Oremus M, de Tezanos Pinto G, Steel D, Paton D, Baker CS (2004). Genetic identification of small cetaceans from the waters of Samoa, South Pacific. Paper SC/56/SM25.
Paton D, Clapham P (2002). Preliminary analysis of humpback whale sighting survey data collected in Fiji, 1956-1958. Paper SC/54/H7.
MAJOR REPORTS AND OTHER RELATED PAPERS
Childerhouse S, Paton D, Rekdahl M (2013). Draft Conservation Management Plan for humpback whales. Prepared for the Department of Sustainability, Environment, Water, Population and Communities, Australia. 59 p.
Findlay, Bannister, Best, Cerchio, Jackson, Loo, Paton, Rosenbaumn, Weinrich, Zerbini (2009). Allocations of catches of humpback whales (1904-1973) for the IWC comprehensive assessment of southern hemisphere humpback whales. Report to the IWC Intercessional meeting on the Comprehensive Assessment of Southern Hemisphere humpback whales.
Paton D. (1996). Management of Cetaceans within NSW Waters. NSW NPWS Discussion Paper.
CONFERENCE PRESENTATIONS AND POSTERS
Cato D, Dunlop R, Noad M, McCauley R, Kniest E, Paton D, Kavanagh A (2013). Addressing Challenges in Studies of Behavioural Response of Whales to Noise. 3rd International Conference – The effects of noise on aquatic life – Budapest, Hungary – August 2013.
Cato DH, Noad MJ, Dunlop RA, McCauley RD, Gales NJ, Salgado Kent CJ, Kniest E, Paton D, Jenner KCS, Noad J, Maggi AL, Parnum I, Duncan AJ. Project BRAHSS: Behavioural Response of Australian Humpback whales to Seismic Surveys. Proceedings of Acoustics 2012 – Fremantle, 21-23 November 2012, Fremantle, Australia.
Cato D, Noad M, Dunlop R, McCauley R, Gales N, Salgado Kent S, Kniest E, Paton D, Jenner C, Noad J, Maggi A, Parnum I, Duncan A (2012). A study of the Behavioural
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Response of whale to the noise of seismic air guns. Proceedings of Acoustics 2012 – Fremantle, 21-23 November 2012, Fremantle, Australia.
Cato D, Noad M, Dunlop R, McCauley R, Gales N, Salgado Kent S, Kniest E, Paton D, Jenner C, Noad J (2012). Studies of the effectiveness of ramp-up as a mitigation method in impacts of noise on marine mammals. 11th European Conference on Underwater Acoustics.
Garland EC, Goldizen A, Cato D, Rekdahl M, Baker CS, Constantine R, Garrigue C, Hauser N, Mattila D, Paton DA, Poole M, Robbins J, Noad M (2009). Dynamic cultural changes to shared vocal traditions: humpback whale song change in the western and central South Pacific Ocean. Abstract submitted to 18th Biennial Conference on the Biology of Marine Mammals, Quebec, Canada.
Garrigue C, Baker CS, Burns D, Childerhouse S, Clapham P, Constantine R, Donoghue M, Franklin T, Franklin W, Gibbs N, Hauser N, Madon B, Mattila D, Russell K, Oremus M, Paton DA, Poole MM, Robbins J (2007). Isolation and interchange among humpback whales on breeding grounds and migratory corridors of the South Pacific. Poster at the 17th Biennial Conference on the Biology of Marine Mammals, Cape Town, South Africa.
Paton DA, Gibbs N, Childerhouse S, Clapham P (2007). Assessment of the current abundance of humpback whales in the Lomaiviti Island Group of Fiji and a comparison with historical data. Poster at the 17th Biennial Conference on the Biology of Marine Mammals, Cape Town, South Africa.
Steel D, Garrigue C, Poole MM, Hauser N, Olavarría C, Flórez-González L, Constantine R, Caballero S, Thiele D, Slooten L, Dawson S, Abernethy B, Oremus M, Russell K, Paton D, Robbins J, Mattila D, Clapham P, Donoghue M, Baker CS (2009). Migratory connections between humpback whales from South Pacific breeding grounds and Antarctic feeding areas based on genotype matching. Abstract submitted to the 18th Biennial Conference on the Biology of Marine Mammals, Quebec, Canada.
Paton D, Kniest E, Burns D, Anderson M (2004). Cape Byron Whale Research Project – A Collaborative whale research project, Cape Byron, Northern NSW. Poster presentation at the National Cetacean Priorities Workshop, Ballina.
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Hinten G, Anderson M, Paton D, Pellow W, Slade RW, Valsecchi E, Baverstock PR (2000). Integration of genetic tagging with photographic identification of Humpback whales migrating along the east coast of Australia. Humpback Whale Conference 2000, Queensland Museum, Brisbane, Australia.
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TABLE OF CONTENTS
DECLARATION ...... I ABSTRACT ...... II ACKNOWLEDGEMENTS ...... IV LIST OF PUBLICATIONS ...... VII LIST OF ADDITIONAL PUBLICATIONS ...... IX LIST OF FIGURES ...... XXIV LIST OF TABLES ...... XXVI LIST OF ABBREVIATIONS ...... XXVIII
CHAPTER 1 INTRODUCTION 1 1.1 General introduction ...... 1 1.2 Biology and ecology ...... 2 1.2.1 General features and morphology ...... 2 1.3 Terminology used to classify humpback whale concentrations ...... 3 1.3.1 Terminology used in this thesis ...... 7 1.4 Distribution and population structure ...... 7 1.4.1 Migratory interchange and movements ...... 9 1.5 History of exploitation, illegal whaling and protection ...... 15 1.5.1 Post-exploitation recovery and current population status ...... 19 1.5.2 Aim of thesis ...... 23 1.5.3 Thesis outline and contributions by others ...... 24
CHAPTER 2 METHODOLOGICAL APPROACH 28 2.1 Introduction ...... 28 2.1.1 Cape Byron Whale Research Project ...... 28 2.1.2 Study site ...... 29 2.1.3 Survey timing and duration ...... 31 2.1.4 Land-based survey ...... 32 2.1.5 Vessel-based survey...... 34 2.1.6 Land-based data analysis ...... 35 2.1.7 Photo-identification ...... 36 2.1.8 Photographic data analysis ...... 36 2.1.9 Sampling permits and ethics approval ...... 37 2.1.10 Collaborative research ...... 38
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2.1.11 Sampling permits and ethics approval ...... 39 2.1.12 Discovery mark data ...... 39 2.1.13 Management and assessment under the EPBC Act ...... 40
CHAPTER 3 AN ASSESSMENT OF SOUTHERN HEMISPHERE HUMPBACK WHALE POPULATION STRUCTURE AND MIGRATORY INTERCHANGE BASED ON DISCOVERY MARK DATA 41 3.1 Abstract ...... 41 3.2 Introduction ...... 42 3.2.1 Background ...... 43 3.3 Discovery Marking ...... 45 3.3.1 Discovery marking schemes ...... 47 3.4 Methodology ...... 48 3.5 Results ...... 50 3.5.1 Overview...... 50 3.5.2 Success of deployments ...... 53 3.5.3 Recoveries – in relation to deployment status ...... 54 3.5.4 Deployment effort ...... 54 3.5.5 Investigation of the location of successful deployments and recoveries ...... 54 3.6 Discussion ...... 61 3.6.1 Why is Discovery tagging important for management? ...... 61 3.6.2 Discovery tagging by breeding groups and feeding grounds...... 63 3.6.3 Potential limitations of the data ...... 68 3.6.4 Migratory Interchange – what drives it? ...... 74 3.6.5 Overall conclusions ...... 75
CHAPTER 4 POPULATION GROWTH OF AUSTRALIAN EAST COAST HUMPBACK WHALES, OBSERVED FROM CAPE BYRON, 1998 TO 2004 79 4.1 Abstract ...... 79 4.2 Introduction ...... 79 4.3 Materials and methods ...... 82 4.4 Analysis ...... 84 4.5 Results ...... 86 4.6 Discussion ...... 90 4.7 Acknowledgements ...... 94
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CHAPTER 5 ABUNDANCE OF EAST COAST AUSTRALIAN HUMPBACK WHALES (MEGAPTERA NOVAEANGLIAE) ESTIMATED USING MULTI-POINT SINGLE-YEAR (2005) SAMPLING AND CAPTURE-RECAPTURE ANALYSIS, AND MULTI-YEAR SINGLE-POINT SAMPLING AND CAPTURE-RECAPTURE ANALYSIS (1999-2005) 96 5.1 Abstract ...... 96 5.2 Introduction ...... 97 5.3 Methods ...... 100 5.3.1 Multi-point single-year capture-recapture ...... 100 5.3.2 Multi-year single-point capture-recapture ...... 107 5.4 Results ...... 111 5.4.1 Multi-point single-year capture-recapture ...... 111 5.4.2 Multi-year single-point capture-recapture ...... 115 Discussion ...... 117 5.5.1 Further considerations ...... 118 5.6 Acknowledgements ...... 119
CHAPTER 6 THREATS AND STATUS OF EAST AUSTRALIAN HUMPBACK WHALES 121 6.1 Abstract ...... 121 6.2 Introduction ...... 122 6.3 Long-term Management objective ...... 123 6.4 Threats ...... 123 6.4.1 Entanglement ...... 123 6.4.2 Vessel disturbance and strike...... 130 6.4.3 Anthropogenic noise ...... 133 6.4.4 Habitat degradation and modification ...... 139 6.4.5 Whaling...... 140 6.4.6 Pollution ...... 141 6.4.7 Over exploitation of prey ...... 142 6.4.8 Disease ...... 143 6.4.9 Increased mortality as a result of reaching carrying capacity...... 143 6.4.10 Climate variability and change ...... 144 6.4.11 Cumulative impacts ...... 145 6.5 Threat Prioritisation ...... 146 6.5.1 Prioritisation process ...... 146 6.5.2 Prioritisation of threats to east Australian humpback whales ...... 147 6.6 Existing management actions – international conventions and agreements ...... 149
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6.7 Existing management actions - national legislation and management arrangements 151 6.7.1 Commonwealth legislation ...... 151 6.7.2 State and Territory legislation ...... 153 6.8 Existing management actions – assessment of effectiveness ...... 154 6.9 Status of the east australian humpback whale population ...... 164 6.9.1 General overview of listing criteria ...... 164 6.9.2 Justification for individual listing of east Australian humpback whales ...... 166 6.9.3 Evaluation of east Australian humpback whales against listing criteria ...... 169 6.10 Recommendations for further research ...... 183 6.10.1 Very high priority research ...... 183 6.10.2 High priority research ...... 184 6.11 Synthesis and general conclusions ...... 187 6.11.1 Primary management objective ...... 187
CHAPTER 7 GENERAL DISCUSSION, SYNTHESIS AND CONCLUSIONS 192 7.1 General discussion ...... 192 7.2 Migratory interchange and stock structure...... 193 7.3 Population growth rate ...... 194 7.4 Current population estimate ...... 196 7.5 Threats and staus of east Australian humpback whales ...... 199
REFERENCES ...... 202
APPENDICES 224 Appendix I: Published paper – Population growth of Australian East coast humpback whales, observed from Cape Byron, 1998 to 2004 ...... 225 Appendix II: Growth rate model in 10-hour sighting rates in Byron Bay 1998-2004 .... 234 Appendix III: Published Paper – Abundance of East coast Australian humpback whales (Megaptera novaeangliae) in 2005 estimated multi-point sampling and capture-recapture analysis ...... 236 Appendix IV Published and unpublished documents containing Discovery mark data and/or analyses ...... 244
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LIST OF FIGURES
Figure 1.1: Summary of photo-identification matches of humpback whales within Breeding Stock E and between Breeding Stock E and F (1999-2006)...... 10 Figure 1.2: Location and number of genotype (dashed line) and photo identification (solid line) matches of humpback whales from Antarctica to the migratory corridor and breeding grounds of Australia, New Zealand and Oceania. .... 11 Figure 1.3: Movements of individual humpback whales satellite tagged at Eden, New South Wales, Australia in 2008...... 12 Figure 1.4: Movements of individual humpback whales satellite tagged at Evans Head, northern New South Wales, Australia in 2009...... 14 Figure 1.5: Catches of humpback whales in the Southern Ocean by the Soviet Union: 1947-1973...... 17 Figure 1.6: Population trajectories for Oceania and east Australia showing changes in population abundance over time...... 20 Figure 2.1: Study site for the Cape Byron Whale Research Project (Cape Byron)...... 30 Figure 2.2: Vadar screen shot for 5 July 2002, CBWRP...... 33 Figure 3.1: Boundaries of six Southern Hemisphere whaling areas adopted by the IWC...... 44 Figure 3.2: Discovery mark...... 46 Figure 3.3: Discovery mark engraved with a unique serial number and an address for return...... 47 Figure 3.4: Number of humpback whales Discovery marked per year in the Southern Hemisphere between 1932 and 1984...... 51 Figure 3.5: Locations of Discovery marking (including all marking attempts) for humpback whales in the Southern Hemisphere...... 52 Figure 3.6: Marking and recovery locations for all Southern Hemisphere humpback whales from which marks were recovered under the IMS. Breeding Stocks A-G and Antarctic Areas I-VI are shown...... 57 Figure 3.7: Duration in years between Discovery tag marking and mark recovery...... 60 Figure 3.8: Relationship between number of days before recapture of Discovery mark and longitudinal movement of humpback whales (R2 = 0.015)...... 61 Figure 3.9: Number of humpback whales killed by Area between 1947 and 1973...... 70 Figure 3.10: Number of whales killed by Breeding Stock and feeding grounds for Areas IV and V between 1947 and 1973...... 70 Figure 3.11: New hypothetical stock structure for Southern Hemisphere humpback whales...... 77 Figure 4.1: Natural log of the mean 10-hour count by year with standard errors...... 87 Figure 4.2: Graph of the mean pod distance off shore and pod composition from 1998– 2004...... 88
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Figure 4.3: Cape Byron and North Stradbroke Island weekly 10-hour counts...... 93 Figure 5.1: Study areas for multi-point single-year capture-recapture analysis of photo- identification data (2005)...... 103 Figure 5.2: Example of a composite image used in analysis...... 104 Figure 5.3: Study area for multi-year single-point capture-recapture analysis of photo- identification data (1999-2005)...... 108 Figure 6.1: Humpback whale entangled in a shark net...... 124 Figure 6.2 Number of reported humpback whale entanglements per year for eastern Australia: 1997-2004 (n=42)...... 126 Figure 6.3: Percentage of entanglements for eastern Australia by source of entanglement: 1997-2004 (n=37)...... 128 Figure 6.4: Percentage of entanglements by month - eastern Australia: 1997- 2004 (n=33)...... 128 Figure 6.5: Humpback whale showing evidence of propeller marks...... 131 Figure 6.6: Humpback whale showing evidence of ship strike...... 131 Figure 6.7: Population trajectories for Oceania and east Australia humpback whales showing changes in population abundance over time...... 173 Figure 6.8: Eastern North Pacific gray whale population size relative to carrying capacity (K)...... 175 Figure 6.9: Known and inferred distribution of humpback whales around mainland Australia...... 177 Figure 6.10: Known and inferred distribution of humpback whales around Antarctica...... 178
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LIST OF TABLES
Table 1.1: Morphology and life history parameters of the humpback whale, Megaptera novaeangliae...... 5 Table 2.1: Duration of annual Cape Byron Whale Research Project surveys...... 31 Table 3.1: Reported deployment outcomes from Discovery marking attempts and recovery rates of Discovery marks by deployment status for Southern Hemisphere humpback whales...... 53 Table 3.2: Number of deployments of Discovery marks by IWC Management Area (south of 50° S) and breeding grounds and migratory corridors (north of 50° S)...... 55 Table 3.3: Number of Discovery marks that were both successfully deployed and subsequently recovered shown by deployment location and IWC Management Area (south of 50° S) and breeding grounds and migratory corridors (north of 50° S)...... 55 Table 3.4: Number of Discovery marks that were both deployed and subsequently recovered shown by recovery location and IWC Management Area (south of 50° S) and breeding grounds and migratory corridors (north of 50° S). ... 56 Table 3.5: IWC Management Areas and Breeding Stocks for Discovery marking and recovery location for all marks recovered...... 58 Table 3.6: Number of humpback whales caught, humpback whales marked, marks returned, proportion of marks returned and proportion of marks returned weighted by whaling effort...... 73 Table 4.1: Yearly summary of data collected from Cape Byron Whale Research Project, 1998-2004...... 89 Table 5.1: Summary of locations, survey effort and equipment utilised for multi-point single-year capture-recapture analysis of photo-identification data (2005)...... 102 Table 5.2: Summary of survey effort and equipment used to collect the multi-year single-point photo-identification analysis of photo-identification data. .... 109 Table 5.3: Frequencies of capture histories for multi-point capture-recapture photo- identification data...... 112 Table 5.4: Results from six full and reduced Mt and Mtb models for multi-point single-year capture-recapture photo-identification data...... 114 Table 5.5: Matches and frequencies for capture histories of humpback whales recorded near Byron Bay, Australia for the multi-year single-point capture-recapture photo-identification data...... 116 Table 5.6: Number of sampled humpback whales estimated to be alive in 2005 based on an estimated 0.95 population survival rate for the multi-year single-point capture-recapture photo-identification data...... 117 Table 6.1: Risk level and actions required...... 147 Table 6.2: Risk prioritisation...... 147
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Table 6.3: Residual risk matrix for east Australian humpback whales...... 148 Table 6.4: Summaries and priorities for management actions for east Australian humpback whales...... 148 Table 6.5: Assessment of management actions and their effectiveness for identified threats to east Australian humpback whales including limitations and potential improvements...... 155
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LIST OF ABBREVIATIONS
ACT Australian Capital Territory AMS Australian Marking Scheme AMSA Australian Maritime Safety Authority ATCM Antarctic Treaty Consultative Meetings BRAHSS The Behavioural Response of Australian Humpback whales to Seismic Surveys BWRP Ballina Whale Research Project CCAMLR Commission for the Conservation of Antarctic Marine Living Resources CASH Comprehensive Assessment of Southern Hemisphere Humpback Whales CBD Convention on Biological Diversity CBWRP Cape Byron Whale Research Project CI Confidence Interval CITES Convention on International Trade in Endangered Species of Wild Flora and Fauna CMP Conservation Management Plan dB Decibel DMD Discovery Marking Database DOE Department of Environment DSTO Defence Science Technology Organisation EAH East Australian humpback(s) EEZ Exclusive Economic Zone ENSO El Niño-Southern Oscillation EPBC Act Environment Protection and Biodiversity Conservation Act 1999 GBR Great Barrier Reef HF High frequency Hz Hertz ICJ International Court of Justice IMO International Marine Organisation IMS International Marking Scheme IPCC Inter-Governmental Panel on Climate Change IUCN International Union for Conservation of Nature
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IWC International Whaling Commission K Carrying Capacity kHz Kilohertz km Kilometre(s) LF Low frequency m Metre(s) MARPOL International Convention of the Preventions of Pollution from Ships MBP Marine Bioregional Planning MF Mid frequency MoU Memorandum of Understanding NH Northern Hemisphere NHH Northern Hemisphere humpback whales nm Nautical miles NOPSEMA National Offshore Petroleum Safety and Environmental Management Authority NRSMPA National Representative System of Marine Protected Areas NSW New South Wales NT Northern Territory NZ New Zealand OPP Offshore Project Proposal Pa Pascal PTS Permanent Threshold Shift(s) Qld Queensland RAN Royal Australian Navy RDMD Revised Discovery Marking Database SA South Australia SCU Southern Cross University SEWPAC Department of Sustainability, Environment, Water, Population and Community SH Southern Hemisphere SHH Southern Hemisphere humpback whale(s) SMS Soviet Marking Scheme SPREP South Pacific Regional Environment Program SPWRC South Pacific Whale Research Consortium
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STLM Sound transmission loss modelling TOP The Oceania Project TTS Temporary Threshold Shift(s) Vic Victoria UNCLOS United Nations Convention on Law of the Sea UNFCCC United Nations Framework Convention on Climate Change WA Western Australia WWF World Wildlife Fund
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CHAPTER 1 INTRODUCTION
1.1 GENERAL INTRODUCTION
This Chapter is a synthesis of the current documented knowledge of the biology and ecology of humpback whales, Megaptera novaeangliae. Specific attention is given to populations in the Southern Hemisphere (SH) and, in particular, the population that migrates along the east coast of Australia.
Humpback whales, like a number of other species of great whales, have been extensively exploited throughout the world by humans. This species is one of the most widely distributed of all mammals being found in all oceans of the world (Clapham 2000). Humpback whales exhibit a strong annual migratory cycle with a tendency to follow consistent migration routes. In some regions a number of these migration routes are along or through continental inshore waters. Humpback whales have a preference for coastal habitats and concentrate in breeding grounds usually in shallow continental waters. These traits have made them highly susceptible to coastal and oceanic whaling operations. These characteristics, combined with their elaborate song and relative ease with which individuals can be identified from natural markings, have also resulted in the species becoming the most intensively studied of all mysticete (baleen) whales (Clapham 2000).
Despite extensive exploitation of humpback whales, many questions remain unanswered about their biology and ecology. In the mid-20th century, researchers such as Willam Dawbin and Graham Chittleborough were pioneers in the field of humpback whale research. In many cases, they worked alongside whalers, collecting valuable data on this species during the peak of their exploitation. During their work, these same researchers found evidence of the depletion of the humpback whale stocks migrating along the west coast of Australia as well as the east coast of Australia and New Zealand and issued warnings, but it was already too late. These populations were pushed at least to commercial extinction, if not to the edge of extinction. In recent years, some populations are showing evidence of a recovery. In other regions, there is either insufficient data upon which to base an assessment and/or current data indicate humpback whale populations remain well below historical numbers with little sign of recovery.
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1.2 BIOLOGY AND ECOLOGY
1.2.1 General features and morphology Humpback whales are a moderately large baleen whale. They are the seventh largest of all cetacean species with a maximum reliable recorded length of 15.4 m (Chittleborough 1965). Generally robust in appearance, their most distinctive external morphological features include a series of ventral pleats common to all Balaenopterids (‘rorquals’); knobs, or tubercles that cover the rostrum; the shape and large size of the pectoral fins; and the shape and colouration of the tail flukes. The scientific name of the humpback whale, Megaptera, originates from the Greek words mega meaning ‘giant’ or ‘large’ and pteron meaning ‘wings’. This refers to the large pectoral fins of the humpback whale, unique to them.
A number of authors have undertaken taxonomic reviews of the genus Megaptera (Matthews 1937; Winn and Reichley 1985; Rice 1998; Clapham et al. 1999; Clapham 2000; Jackson et al. 2014). Lillie (1915), Matthews (1937) and Chittleborough (1965) reported several colour morphs of the humpback whale. Humpback whales wintering in the Southwest Pacific and off Western Australia generally have more white pigmentation, particularly on their ventral and lateral thorax and abdomen, than those observed wintering in the North Pacific or elsewhere in the Southern Ocean. Humpback whales that migrate to Hawaiian waters are predominantly black, apart from the ventral side of the fluke, and a higher percentage of animals are observed with white or light coloured dorsal surfaces on their pectoral fins. Historically it was proposed that these two populations (Northern Hemisphere (NH) and SH) be divided into two sub-species (M.n. novaezelandiae in the SH and M.n. novaeangliae in the NH). Baker et al. (1994), however, demonstrated that there was very little genetic separation of worldwide stocks and Rice (1998) supports this argument suggesting that there is insufficient separation, either genetically or morphologically, to warrant sub-speciation. However, a study on the global diversity and oceanic divergence of humpback whales by Jackson et al. (2014), has identified more recent genetic evidence suggesting humpback whales in the North Pacific, North Atlantic and SH are on independent evolutionary trajectories, supporting taxonomic revision of M. novaeangliae into three subspecies. For a full taxonomic review of the species see Rice (1998) and Clapham and Mead (1999). For a full review of the global diversity and oceanic divergence of humpback whale stocks see Jackson et al. (2014).
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Like the pectoral fin, the fluke is large and its width can be up to one third the body length (27-33.5% - Tomlin 1967). The dorsal surface is usually dark and the ventral surface can have a varying degree of white pigmentation that can be used to identify individuals (Katona et al. 1979). Flukes of some animals contain numerous scars, some of which are believed to be teeth marks of killer whale (Katona 1980). The trailing edge of the fluke is usually deeply scalloped and has a notch in the centre. The combination of notch, scallops and other permanent markings such as colouration patterns are distinctive to individual animals.
As with most baleen whales, female humpback whales are larger than males, being typically 1 to 1.5 m longer (Chittleborough 1965). Apart from size (which cannot usually be used to differentiate reliably between the sexes), the only other external difference is that females have a semi-spherical lobe posterior of the genital opening. This lobe is absent in males (Glockner 1983). In addition, the separation between the genital slit and the anus is considerably wider in males than in females (True 1904). Table 1.1 summarises life history parameters for the humpback whale.
1.3 TERMINOLOGY USED TO CLASSIFY HUMPBACK WHALE CONCENTRATIONS
Various terms including; populations, meta-populations, subpopulations, breeding stocks, groups, subgroups and areas, have been used diversely in the literature to describe the separation of concentrations of humpback whales throughout the oceans of the world.
These terms and their definitions differ among authors and the location of their study sites. The term ‘population’ has been used in a number of ways to describe varying concentrations of humpback whales. This includes worldwide population; SH or NH population (Brown et al. 1995); circumpolar population (Baker et al. 2000); South Pacific population (Dawbin 1956a); and east Australian population (Bryden 1981; Paterson and Paterson 1984). The terms meta-population and subpopulation have also been used to describe sections of a larger group or population.
A number of additional terms have been used to further define concentrations of whales in the SH. For example, Kellog (1928) first used the term ‘stock’ to refer to whales using geographically distinct breeding and calving grounds, and non-overlapping feeding grounds.
Based on Antarctic catch data for southern baleen whales, Hjort et al. (1932) proposed to divide the Antarctic into five Areas within the SH and each Area contained a ‘Group’ of
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humpback whales that generally moved north and south between breeding and feeding areas. These Areas were numbered I – V and the whale groups within each of these five Areas were known as Group I – Group V. This proposal was implemented following an international conference held in London in 1937. The original intent of these areas was as management regions for which whaling quotas were issued and regions were closed to whaling (so-called Sanctuary Areas) under the International Agreement for the Regulation of Whaling (Mackintosh 1965).
Following preliminary results from Discovery marking activities (a tagging technique where cylindrical steel spikes, each marked with a serial number were fired into cetaceans and recovered once the whale was killed in whaling operations), Mackintosh (1942) further defined the term ‘Group’ to denote a concentration of whales occupying a tropical breeding ground and a feeding area with limited or no mixing with adjacent concentrations of whales. Following on from Hjort et al. (1932), Mackintosh (1942; 1965) expanded these original five Groups to six following further review of Discovery mark data.
The original stock structure management units were based on Antarctic feeding ground operations and information from that region. However, with an increase in research being undertaken on the breeding grounds and concurrent with the development of new research techniques (for example genetics), the International Whaling Commission (IWC) (1998) recognised a new stock structure system based on breeding stocks and identified seven distinct breeding stocks. To differentiate between these breeding stocks and those originally proposed by Mackintosh, the IWC identified them as Breeding Stocks A-G. However, additional analysis of data resulted in the further subdivision of some breeding stocks into Breeding Stocks E1, E2, and E3 (Anonymous 2003a).
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Table 1.1: Morphology and life history parameters of the humpback whale, Megaptera novaeangliae. Source: Modified from Clapham (2000) and updated with more recent information.
Mean Range/Max Other Reference/Notes Adult body size (kg x Various sources, reviewed by Lockyer (1976). Individual
1000) weight at a given length varies greatly by season and female reproductive condition. Male - - 27.7 Female - 24.8-40.8 - Adult body length (m) Chittleborough 1965; Matthews 1937. Other reported values up to 16.2 (female) and 17.4 (male), but reliability of Male 13.0 14.8 - measurements is unknown. Female 13.9 15.5 - Length at birth (m) 4.2 3.96-5.7 - Clapham et al. 1999 Length at Clapham et al. 1999 - 8-10 - independence (m) Length of gestation 11.5 11-12 Chittleborough 1958a (months) Chittleborough 1958a; Clapham and Mayo 1987, 1990; Baraff Weaning age (months) 11 10-12 and Weinrich 1993. Independent feeding can occur at six months. A few calves (ca. 5%) remain associated with their mothers for a second year. Inter-birth interval Clapham and Mayo 1990; Barlow and Clapham 1997 2.4 1->5 Mode = 2 (years) 0.966 east Zerbini et al. 2010 Adult mortality 0.96 0.92-0.98 Australia
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Mean Range/Max Other Reference/Notes Calf mortality Barlow and Clapham 1997. Figures estimated from modelling - - 0.125 (first year) – reliability unknown. - 0.150-0.241 0.182 Gabriele et al. 2001. Note small sample size may bias the result. Length of estrus (days) unknown Estrus duration is unknown for any mysticete. Breeding season Kellogg 1929; Chittleborough 1958b; Chittleborough 1965; Baker and Herman 1984 Northern Hemisphere Dec-Apr Southern Hemisphere Jun-Oct Nishiwaki 1959; Chittleborough 1965; Clapham 1992. Note Age at first birth Gabriele et al. (2007) report first calving at 8-16 years, which 6 5-8 - (years) is more consistent with that of other rorquals (around 10 years), however this may be a reflection of different ecological conditions. Age at sexual maturity Chittleborough 1965; Clapham 1992
(years) Male 5 4-8 - Female 5 4-8 - Chittleborough 1965; Polanowski et al. 2014. Likely significantly greater than this value given the removal of older animals by whaling and known longevity of other Maximum life span Balaenopterids. Best (2001) suggests that Chittleborough’s >52 (years) interpretation of the accumulation rate of earplug growth layers may have been incorrect and therefore animals may be much longer living than previously recorded. Polanowski et al. 2014 describes the use of epigenetic age estimate techniques for the determination of individual animal ages.
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1.3.1 Terminology used in this thesis For the purposes of this thesis the following definitions have been used:
The term ‘Area’ will be based on the original Hjort et al. (1932) divisions of the SH, but amended to include the six discrete regions proposed by Mackintosh (1942) and adopted by the IWC;
‘Groups’ of humpback whales will be defined as concentrations of whales within the identified feeding ‘Areas’ numbered I – VI as per Hjort et al. (1932) and amended by Mackintosh (1942). These Groups will be identified as Groups I –VI;
The use of the term ‘Breeding Stock’ will be based on the IWC classification for Groups A-G (Anonymous 2003a); and
The term ‘population’ will be used in two ways. First, as a general term that relates to all humpback whales within the SH; and second, as a specific term in reference to the discrete breeding stocks of whales recognised by the IWC (that is, the east Australian humpback whale (EAH) population – IWC Breeding Stock E1). While these are varying and slightly divergent definitions of population, these are commonly accepted and this is how they are applied and utilised by the IWC.
1.4 DISTRIBUTION AND POPULATION STRUCTURE
Humpback whales are found in all oceans of the world (Clapham 2000). They undertake migrations annually from the summer feeding grounds in the higher latitudes (generally in a north/south orientation), to the winter breeding grounds in the lower latitudes and display strong site fidelity to natal breeding areas (Chittleborough 1965; Dawbin 1966). One population appears to be an exception to this rule. The breeding stock in the Arabian Sea appears to be non-migratory and is reported to be reproductively isolated from the SH population of humpback whales (Mikhalev 1997; Gales et al. 2011).
Continental landmasses currently separate humpback whales in the NH into two oceanic subpopulations, the North Atlantic and the North Pacific (Mackintosh 1965). In the SH, however, humpback whales form a single circumpolar meta-population distributed throughout the Southern Ocean (Baker et al. 2000). Within each oceanic basin, humpback whales undertake annual migrations, averaging 10,000 kilometres (km) return. Some of
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these migrations are almost entirely across open oceans, while others are at least partially coastal, between summer feeding grounds and winter breeding and calving grounds.
Humpback whales tend to spend the summer months in the higher latitude feeding grounds and migrate to the lower latitude breeding grounds in the winter. As the NH and SH have opposing seasons, it was generally assumed that humpback whales from the two hemispheres did not meet chronologically or geographically and therefore would not be expected to interbreed. However in 1929, Kellogg raised the potential for migratory overlap near the equator between the populations from the two hemispheres. Given the geographical overlap and loose timing of migration of some individuals, there is potential for inter- hemispherical breeding in this region. Photo-identification studies have since shown that Southern Hemisphere humpback whales (SHH), when in the breeding grounds on the eastern tropical Pacific off the coast of Central America, migrate as far north as 9°25’ N (Steiger et al. 1991; Acevado and Smultea 1995; Flórez-González et al. 1998; Rasmussen et al. 2001). Historical genetic studies support this theory and show evidence of gene flow in south and north directions (Baker et al. 1993, 1998; Medrano-González et al. 1995; Palsbøll et al. 1995). Based on recent genetic evidence, however, Jackson et al. (2014), suggest that humpback whales in the North Pacific, North Atlantic and Southern Hemisphere are on independent evolutionary trajectories, supporting taxonomic revision of M. novaeangliae into three subspecies.
Although regions of potential migratory overlap for NH and SHH have been confirmed near the equator, Baker (2000) states the three major oceanic breeding stocks are reproductively isolated from each other. Within each major oceanic breeding stock, discontinuous patterns of seasonal distribution and observations of migratory movement by marked individuals suggest that humpback whales form relatively discrete subpopulations not separated by obvious geographic barriers (Kellogg 1929; Mackintosh 1965). Within each ocean there are several ‘stocks’. Genetic studies have generally shown high levels of genetic heterogeneity even among stocks within the same ocean (Mackintosh 1942; Baker et al. 1990, 1993, 1994, 1998; Palsbøll et al. 1995; Valsecchi et al. 1997; Calambokidis et al. 2001; Jackson et al. 2014).
The IWC currently recognises seven distinct breeding stocks of humpback whales in the SH (A-G - IWC. 2005; 2006). Chittleborough (1965) concluded that the population of humpback whales that migrate along the east coast of Australia comprises part of the Area
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V population (130° E to 170° W). This population was previously known as Group V. Recent studies suggest that the region contains several populations that intermingle to a variable but probably small degree (Garrigue et al. 2000, 2011a). Group V humpback whales have now been divided into three sub-stocks known as: Breeding Stock E1, those wintering off the Australian east coast; E2, those migrating past Norfolk Island and wintering around New Caledonia; and E3, those wintering around Tonga (Bannister 2005; Olavarría et al. 2006; Paton et al. 2006). Breeding Stock E1, the EAH population, is thought to be the largest of these.
The winter breeding area for E1 is off the east coast of Australia which, while widely dispersed inside the Great Barrier Reef, is probably centred on the waters of the southern lagoon between 20°-22° S (Smith et al. 2012). Breeding humpback whales in this region show a preference for shallow (30-58 m, highest probability 49 m) and warm waters (21-23° C, highest probability 21.8° C; Smith et al. 2012). The migration to and from these waters is along the eastern continental coastline. Off the headlands of the southern coastline of Queensland (Qld) and northern coastline of New South Wales (NSW) the migratory corridor is narrow. Here most whales pass close to land and so are available for land-based counts (Bryden 1985; Bryden et al. 1990; Paterson 1984, 1991; Paterson et al. 2004; Noad et al. 2008).
1.4.1 Migratory interchange and movements The SH population of humpback whales forms a circumpolar distribution on high latitude feeding areas in the Southern Ocean. The lack of physical barriers creates potential for longitudinal movement, which may lead to population mixing and opportunities of interchange of individuals on the feeding area, as well as potentially during migration. While there are seven distinct humpback whale breeding stocks recognised in the SH, increasing evidence suggests that there is a weaker population structure than the NH populations, where foraging areas are numerous, discrete and in some cases physically separated.
Discovery mark tagging was the first method of obtaining information in relation to movement patterns of humpback whales in the SH (Rayner 1940). Discovery mark recoveries indicated a low level of migratory interchange between eastern Australia and New Zealand (NZ) with dispersal to the putative feeding areas of Area V (Chittleborough 1965; Dawbin 1966). In addition, Brown (1957) reported a whale marked in Tonga was recovered in Area I. This represents a longitudinal distance of 7,413 km or 90° of longitude.
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Photo-identification matches have connected humpback whales from Breeding Stock E1 on the east coast of Australia to Breeding Stock D on the west coast of Australia – a single whale moving from the east to the west coast (Rock et al. 2006). Additionally, whales from the eastern portion of Breeding Stock E3 (that is, Tonga and American Samoa) have been connected with Breeding Stock F (French Polynesia) (Garrigue et al. 2002, 2007). There have also been a number of movements within Breeding Stock E including: Hervey Bay to Cook Strait, NZ (Garrigue et al. 2007; Franklin et al. 2008); Byron Bay and Hervey Bay to New Caledonia (Garrigue et al. 2000, 2007); and Ballina to Tonga (D. Burns pers. comm.), see Figure 1.1.
Figure 1.1: Summary of photo-identification matches of humpback whales within Breeding Stock E and between Breeding Stock E and F (1999-2006). Note: arrows represent the detection of movement of whales between sites as revealed from photo-identification matches, with numbers indicating the number of individual whales detected to move between sites between 1999 and 2004. Figure modified from: SPWRC 2008.
In addition, there are a number of connections between Breeding Stock E1 (including Hervey Bay, Eden, Point Lookout, and the Whitsunday Islands) with Antarctic Area V feeding grounds (Kaufman et al. 1990; Rock et al. 2006; Franklin et al. 2012; Constantine et al. 2014), see Figure 1.2. This information (and in particular the recent findings of Constantine et al. 2014) supports the finding by Franklin et al. (2012) that the Balleny Islands region is an important feeding area within the Antarctic for EAH (Breeding Stock E1). Robbins et al. (2011) also report a return movement of two whales between American
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Samoa (Breeding Stock E3) and the Antarctic Peninsula (Feeding Area I). This represents a longitudinal distance of 9,406 km or 108° of longitude.
Supporting these photo-identification connections, genotype data have provided further evidence of a low level of migratory interchange between neighbouring SHH breeding populations (Olavarría et al. 2006; Steel et al. 2008, 2011; Anderson 2013; Schmitt et al. 2014). In addition, genotype data have supported Discovery mark and photo-identification connections between Breeding Stock E and the Antarctic feeding areas (Steel et al. 2011; Constantine et al. 2014), see Figure 1.2.
Figure 1.2: Location and number of genotype (dashed line) and photo identification (solid line) matches of humpback whales from Antarctica to the migratory corridor and breeding grounds of Australia, New Zealand and Oceania. Source: Constantine et al. 2014. Note: CETA = Distribution des Cétacés en Terre Adelie.
Genetic analysis has the ability to not only show connections between locations for individual animals but through Nuclear DNA analysis can reveal the level of relatedness among whales within the same region. The analysis of genetic samples from the east
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Australia migratory corridor has revealed the potential for some sub-structure within the population of whales migrating north along the east Australian coastline (Valsecchi et al. 2010; Anderson 2013; Schmitt et al. 2014).
Satellite tagging is another technique that can demonstrate migratory interchange and movements of whales (Read 2009). In 2008, a total of 16 satellite tags were attached to southbound humpback whales at Eden, southern NSW. This was the first tagging project involving animals from Breeding Stock E1. The tags remained attached for between 3 and 156 days and provided movement data of individual whales from Eden to the Antarctic feeding grounds (Figure 1.3). The tagged whales took one of three different routes south from Eden. Five animals headed south from Eden down the east coast of Tasmania before spreading out into the Antarctic feeding ground between 150° E and 175° E (Area V). Six animals headed southeast from just south of Eden towards the southern tip of NZ before heading south to the Antarctic feeding grounds (Area V). However another two animals (a female with a calf) headed southwest though Bass Strait and continued to a location approximately 100° E in Antarctic feeding Area IV.
Figure 1.3: Movements of individual humpback whales satellite tagged at Eden, New South Wales, Australia in 2008. Source: Australian Antarctic Division.
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A further tagging program was undertaken off Evans Head, northern NSW in 2009. A total of 13 whales were tagged during the northern migration with the tags remaining attached for 1-60 days. All of the animals migrated north into the breeding grounds within the Great Barrier Reef (Figure 1.4). None moved into the South Pacific during the northern or southern migrations. However, the small sample size and short period of tag retention is a potential limitation with this study (Gales et al. 2010). Acknowledging its small sample size (especially for females: n=2), this program showed a differential in residency time on the breeding grounds between males and females. Tagged females stayed a short period on the breeding grounds (approximately seven days) whereas the mean period for males (n=8) was approximately a month (Gales et al. 2009).
Analysis of humpback song data is another useful indication of potential migratory interchange. Male humpback whales are well known for producing a highly complex, rapidly changing vocal displays called ‘songs’. While the true function of song is poorly understood, it is thought to have intersexual function, whereby males use song to solicit receptive females during the breeding season (Noad et al. 2000; Smith et al. 2008). It appears that all singers within a population sing the same song in a given year, and that song may change from year to year. Noad et al. (2000) first documented song exchange between the west and east Australian populations. Further analysis of song by Garland et al. (2011) has demonstrated additional examples of cultural exchange of humpback whale song that originated in Western Australia and were transmitted over a number of years to east Australia and through a number of populations in the southwest Pacific.
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Figure 1.4: Movements of individual humpback whales satellite tagged at Evans Head, northern New South Wales, Australia in 2009. Source: Gales et al. 2010.
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1.5 HISTORY OF EXPLOITATION, ILLEGAL WHALING AND PROTECTION
The tendency of humpback whales to follow seasonal migrations between high latitude feeding grounds and low latitude breeding grounds, along with their preference for coastal waters of SH continents as migratory corridors, have made them susceptible to coastal whaling in tropical and sub-tropical waters.
Commercial whaling was commenced in the 17th Century by Europeans and Americans. Until the development of the steam chaser and the harpoon gun in the 1860s, humpback whales and other Balaenopterids, were not considered particularly desirable due to their comparatively high swimming speed and lack of buoyancy. With the development of ‘modern whaling techniques’ in the late 19th Century, humpback whales, along with fin, sei and blue whales were heavily exploited in the North Atlantic. As a result, low catches of humpback whales by 1900 in the North Atlantic resulted in exploitation in other regions, in particular the Southern Ocean and North Pacific. This exploitation occurred in a number of waves (for example 1910s, 1930s, 1950s), broken by periods of war (Winn et al. 1985).
Prior to exploitation, the population of the SHH was estimated at 90,000-100,000 (Chapman 1974). Access to Russian whaling data released in the late 1990s, however, shows that over 200,000 humpback whales were killed by modern whaling in the SH since the beginning of the 20th Century (Findlay 2001; Clapham and Baker 2009).
Townsend (1935) examined the available log books of American whaling ships operating during the 19th Century and produced a series of charts indicating the distribution of a range of species based on capture records. Humpback whales were taken adjacent to the NZ coast, however, the greatest number of humpback whales taken were from the region of Tonga and the Chesterfields. Although sperm whales were their prime target, a total of 2,883 humpback whales were taken worldwide by American whalers in the 19th Century. Smith and Reeves (2003) undertook a more detailed review of these historical whaling data and determined that the 2,883 humpback whales taken was likely to be an underestimate. It is unlikely, however, that this whaling activity had any significant impact on the humpback whale populations at that time (Townsend 1935; Paterson 1984).
The development of shore-based whaling in Australia, NZ and Africa, along with the Antarctic pelagic whaling industry resulted in year-round exploitation of SHH stocks.
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Shore-based whaling stations operated in Australia and NZ from early in the 19th Century, however, these stations concentrated on the southern right whale due to the high value of the oil obtained from this species, their preference for inshore waters and the fact that they floated (unlike humpback whales) once harpooned. Most of these stations had closed by the 1840s due to the collapse of the southern right whale populations. Occasional humpback whale captures were made in that period and after the decline of the southern right whale industry a few humpback whales continued to be taken by whalers using hand harpoon at Twofold Bay on the southeast Australian coast and at Norfolk Island up until approximately the 1930s.
Mechanical whaling stations targeting humpback whales opened in NZ at Whangamumu in 1910, the Cook Strait in 1911, and at Great Barrier Island in 1956 (Cawthorn 1999). In the early 20th Century, a number of unsuccessful attempts were made to establish pelagic whaling in Australia (at Jervis Bay among others), however, it was not until after World War II with an increase in the demand for oil that modern mechanical whaling was established in Australia. Whaling commenced at Albany, Western Australia in 1947, Point Cloates in 1949, and Carnarvon in 1955 (Findlay 2001). On the east coast of Australia, whaling commenced at Tangalooma in 1952, Byron Bay in 1954 and Norfolk Island in 1955 (following an earlier attempt in 1948). In addition to these whaling activities, the Tongans practised traditional humpback whaling modified from 19th Century American methods (Paterson 2001).
In both Australia and NZ, humpback whales were plentiful until the early 1960s when the stocks collapsed. The Soviet Union undertook extensive legal and illegal whaling operations in the Antarctic between 1948/49 and 1971/72. During this time they reported taking 133,621 whales in Antarctic waters. However, recently released data have indicated that the true catch of whales was 227,180 during the same period, an under reporting of over 93,000 humpback whales or 41% of the likely true catch (Brown et al. 2003; Clapham et al. 2009).
During the first eleven years of Antarctic whaling voyages, the Soviet fleet concentrated primarily on fin whales. In the summer of 1957/58, this fleet began to concentrate on humpback whales. Whaling was intensive and in excess of the quotas issued by the IWC. Figure 1.5 indicates the number of humpback whales taken from Antarctic waters between 1947 and 1973. These new data indicate that the Soviet fleets illegally took 42,760 humpback whales during this period (Clapham et al. 2009). Not only did the Soviet fleet
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significantly exceed the quota granted by the IWC, but also the entire quota allocated to all countries conducting whaling (that is, 1,500 humpback whales). During 1959/60 and 1960/61, the Soviet fleet took 18 times and 40 times respectively, the quotas of humpback whales allocated to them by the IWC.
16000
14000
12000
10000
8000
6000
4000 Number of whales whales of Number caught
2000
0
1950 1963 1947 1948 1949 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 Year
Figure 1.5: Catches of humpback whales in the Southern Ocean by the Soviet Union: 1947-1973. Source: Clapham et al. 2009.
Mikhalev (2000) reported that of the 12,400 humpback whales taken by the Soviet fleet in Area V in 1959/60, at least 4,000 were taken west of 147° E and, thus, were almost certainly part of the EAH stock. In addition, around 10,000 humpback whales were also taken west of 165° E, the majority of which were also probably part of the EAH stock. It is worth noting that these catches coincide with a catastrophic decline in catch per unit effort between 1959 and 1960 on the east coast of Australia (for example, Chittleborough 1965). With continued ongoing illegal catches in the Southern Ocean there was an even more marked drop in catch per unit effort in 1961 and 1962.
During the late 1950s and early 1960s in the terminal phase of Area V humpback whale whaling, the east Australian shore stations captured lean southbound humpback whales in an attempt to fill their quotas. While there were strict regulations on the minimum size of whales that could be taken and quotas were reduced in the early 1960s, the stock was commercially exhausted by 1962 and the IWC belatedly banned the capture of SHH in 1963.
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Bans had been in place in the North Atlantic since 1956 – and a worldwide ban was implemented in 1966. Despite the ban on whaling for humpback whales, the Soviets continued to take them illegally in Antarctic waters until 1967/68 after which time humpback whales were rarely encountered there. When they were, whaling continued. The Soviet fleets also demonstrated total disregard for the quotas and bans for other species of whales, also taking blue whales and southern right whales (protected since 1937) during the same period (Yablokov 1994; Mikhalev 2000). Total numbers of humpback whales taken in Eastern Australia, NZ, Norfolk Island and Tonga accounted for approximately 5% of the whales taken by the Soviets in Area V. Low levels of traditional whaling continued in Tonga until 1978 (Paterson and Paterson 1984).
By 1966, it was estimated that only a few thousand humpback whales remained from a worldwide pre-whaling population of at least 100,000 (Chapman 1974) and possibly in excess of 150,000 animals (Winn and Reichley 1985).
In 1963, the IWC implemented a worldwide ban on whaling for humpback whales. Protection of humpback whales was further strengthened by the IWC in 1979 and 1994 with the declaration of the Indian and Southern Oceans respectively, as whale sanctuaries. The IWC also declared a worldwide moratorium on commercial whaling in 1986. More recently, Australia and NZ have been instrumental in the attempts to have the central and western South Pacific declared a whale sanctuary. Although the proposed South Pacific Whale Sanctuary has failed to achieve the necessary three quarters majority to be ratified by the IWC, a number of nations including the Cook Islands, French Polynesia, Niue, Fiji, part of New Caledonia and Australia have declared whale sanctuaries within their Exclusive Economic Zones. In addition to these sanctuaries, NZ and Vanuatu have legislation in place that protects whales within their territorial waters. Whales in the Kingdom of Tonga are protected by a Royal decree from the King. The humpback whale is listed in Appendix 1 of the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES), which prohibits member countries from trading in humpback whales or products from them.
In 2008, the International Union for Conservation of Nature (IUCN) reviewed the status of humpback whales on the Red List of Threatened Species. During this review, reflecting the recovery of humpback whales globally, the IUCN downgraded their global conservation status from a classification of ‘Vulnerable’ to that of ‘Least Concern’. Despite the
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encouraging signs of recovery of most humpback whale populations globally, concerns remain about a number of discrete and small sub-populations for which information on status and trends in recovery are lacking or point to a slow or lack of recovery.
While the understanding of recovery of humpback whales on the east coast of Australia is good, the current status and understanding of the recovery of humpback whales in other parts of the southwest Pacific (including Breeding Stock E2, E3, F1 (French Polynesia) and F2 (Cook Islands) is poorly understood but thought to be low. As a result, the IUCN upgraded the classification of these populations, including EAH, from Threatened to Endangered. Even though the EAH population is currently showing strong signs of recovery, the IUCN listing included them as Endangered because it was not possible to estimate the recovery of east Australia separately from the rest of Oceania due a lack of data on the locations of historic catches.
1.5.1 Post-exploitation recovery and current population status Prior to the 1950s, there was little exploitation of the EAH population and the size of the entire Group V meta-population was estimated to be 10,000 whales (Chittleborough 1965). Following review of the previously unreported illegal catches in the Southern Ocean, this was upwardly revised to 26,000 whales (Bannister and Hedley 2001). Jackson et al. (2006) estimates the original size of Group V (Breeding Stocks E and F) to be 35,000-40,000, while Jackson et al. (2008) estimate the pre-exploitation size of the EAH population to have been 22,000-25,700 and the combined Oceania populations (E2, E3 and F) to be 17,800-26,600 (Figure 1.6).
In 1952 industrial shore-based whaling commenced and together with massive illegal pelagic whaling in the Southern Ocean, resulted in over exploitation leading to the population collapsing by 1962. Estimates of the remaining Group V population vary between 34 and 137 (Paterson et al. 1994); 200 (Chapman 1974); and 500 (Chittleborough 1965). Analysis of previously unreported Soviet catches (Bannister and Hedley 2001) estimated that the remaining Group V population was at an all-time low of 104 whales in 1968 rather than 1962. Further modelling of the catch data by Jackson et al. (2009) has agreed with Bannister and Hedley’s (2001) assessment of the EAH population reaching an all-time low in 1968, however, they estimated the minimum abundance to be between 190 and 205. The populations of the EAH and southwest Pacific breeding groups in Group V (Breeding Stocks E and F) were not separately estimated. While the distribution of surviving
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whales was not known, the rapid recovery of EAH and apparent lack of recovery of whales migrating past NZ and other regions in Oceania, suggest that most of these were from the EAH population.
Figure 1.6: Population trajectories for Oceania and east Australia showing changes in population abundance over time. Median trajectory (solid line) and 95% posterior probability intervals (dashed lines) are shown in blue for Oceania and red for east Australia. (Source: Jackson et al. 2009).
A number of long-term post-whaling surveys of the EAH population have been conducted. These land-based surveys were initiated at Point Lookout, North Stradbroke Island (two independent surveys at this location) and Cape Byron, Northern NSW in the late 1970s. Although the two surveys at Point Lookout were conducted independently, and despite the use of different methodology and analysis, both are in general agreement in relation to the numbers of whales passing the coast (Bryden 1985; Bryden and Slade 1987; Bryden et al. 1990, 1996; Brown 1997; Brown et al. 2003; Noad et al. 2006, 2008, 2011a,b; Paterson and Paterson 1989, Paterson et al. 1994, 2001). Paterson et al. (2001) estimated the EAH population passing Point Lookout in 1999 to be 3,600 (+ 440), whereas Brown et al. (2003) estimated 3,634 (+ not available) for the 2000 season. Brown et al. (1995) suggested that the total EAH population may be considerably larger due to the likelihood that in any one year,
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up to 55% of females may not migrate from Antarctic waters. Brown et al. (1995) results have the potential of sampling bias. The author was involved in assisting Brown in undertaking the study and is familiar with the methodology used. In his study Brown determined the sex of humpback whales from a genetic sampling program focusing on the relatedness of whales within individual pods. The methodology introduces a potential bias towards the sampling of males because they have a longer residency on the breeding grounds than females and make up a greater proportion of the larger, more obvious, surface active pods, which are more easily sighted by researchers.
Surveys conducted at Point Lookout (Stradbroke Island, Qld) prior to 2004 by Bryden et al (1990; 1996) provide estimates of annual rates of population increase (with 95% CI) at 12.3% (10.1-14.4%) whereas Paterson et al. (2004) provide an estimate of 10.5% (10.0- 11.1%). More recent surveys conducted by Noad et al. (2006, 2008, 2011a,b) at Point Lookout, estimated the rates of growth as 10.9% per annum (95% CI 10.5-11.3%). When the Point Lookout data are assessed in the context of previous surveys from the same location, the high long-term rate of population growth was maintained at 10.9% per annum (95% CI 10.5-11.3%). There is no evidence that the rate of growth is slowing.
Using land-based survey data from Point Lookout, Noad et al. (2008) obtained a population estimate of 9,683 (95% CI 8556-10,959). In addition Noad et al. (2011a) used an updated land-based correction factor for groups available but missed in 2004 and the updated rate of population growth, to estimate absolute abundance in 2010 at 14,522 whales (95% CI 12,777-16,504). This may, however, be an underestimate due to possible non-migration of some cohorts (Noad et al. 2011a).
These growth rates are among the highest recorded for any humpback whale population in the world (but similar to those of the Australian west coast population acknowledging that there is considerable uncertainty associated with the confidence intervals for the west Australian humpback whale population) and are close to the theoretical reproductive limit of the species (Best, 1993; Brandao et al. 1999; Bannister and Hedley 2001; Zerbini et al. 2010). The rates of increase are also remarkably consistent over time with a very tight correlation between log-transformed, normalised whale counts and year.
In addition to the land-based surveys conducted on the east coast of Australia, Chaloupka et al. (1999) used a complex mark-recapture model to analyse photo-identification data collected in Hervey Bay, South Eastern Qld. Chaloupka et al. (1999) reported that the rate
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of increase in the EAH population was only 6.3% (95% CI 2-11%) between 1988 and 1996. This differential in the population growth rate between the land-based methodology at Point Lookout and mark-recapture methods used in Hervey Bay could be explained by recent evidence showing the group of whales utilising Hervey Bay may be a sub-group of the eastern Australian humpback whale population (E1) and, therefore, may have a different recovery rate to that of the E1 population (Franklin 2014). This finding is supported by Chaloupka et al. 1999 whom support the theory of a sub-population using Hervey Bay, as well as Schmitt et al. 2014 and Valsecchi et al. 2010 who report genetic evidence of a sub- population within the east Australian humpback whale population. At present the data from the Cape Byron survey, initiated by the Australian Whale Conservation Society and continued by the author from 1995, has not been published and is the subject of this thesis (see Chapter 4 and Chapter 5).
Long-term photo-identification and genetic studies of humpback whales were commenced in the Oceania region late in the 1980s. These studies undertaken by members of the South Pacific Whale Research Consortium (SPWRC – of which the author is a founding member), have documented the current status and movement patterns of humpback whales in the region. In addition to assessing the status of humpback whales within Oceania, SPWRC (in collaboration with a number of Australian-based researchers) has undertaken an assessment of interchange between the humpback whale breeding grounds within Oceania and east Australia. This assessment has used photo-identification and genetic matching (Olavarría et al. 2006, Steel et al. 2008, Anderson et al. 2010; Garrigue et al. 2011a,b), and revealed a low level of longitudinal intermingling of individual humpback whales between breeding grounds in the southwest Pacific.
Currently there is no available rate of increase for the humpback whale population in the Oceania region. Although there are limited long-term data currently available for other regions, general information on humpback whales in the South Pacific outside the EAH stock indicates that the recovery of this species has been slow throughout Oceania (Garrigue et al. 2000; Hauser et al. 2000; Paton and Clapham. 2002; Gibbs et al. 2003). Further long- term research is required in order to determine the current status of humpback whales in many parts of the South Pacific.
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1.5.2 Aim of thesis Previous research has documented the decline and initial slow recovery of the population of humpback whales that migrates along the east coast of Australia (Paterson 1980, 1985, 1986, 1987). In recent years, the EAH population (Breeding Stock E1) has been shown to be recovering at the maximum biological population growth rate for the species. The research in this thesis was developed to investigate key aspects of the dynamics of population recovery, including: estimates of abundance and rates of recovery; movement patterns; and an assessment of management actions and their influence on recovery.
These data add to a growing body of information and improve the understanding of the status of this population of whales recovering from the edge of extinction due to over exploitation. This research will allow more informed management decisions to be made based on a better understanding of factors affecting the recovery of the EAH population. Some of the results of this thesis have already been used to inform this process (that is, the use of Discovery mark data to assist in the allocation of stock structure as part of the IWC Comprehensive Assessment of Southern Hemisphere Humpback Whales - CASH).
While the focus of this thesis is on the EAH population (Breeding Stock E1), other SH populations, in particular the western Australian population (Breeding Stock D) and those populations in the South Pacific (Breeding Stocks E2, E3 and F), are also discussed in some sections. This is entirely appropriate and reflects the linkages between these groups.
This thesis has four specific aims:
1) To document the movement patterns of EAH based on existing and previously unpublished Discovery mark data with a view to developing more robust models of stock structure in order to improve management and conservation of SHH stocks;
2) To estimate the recovery rate of EAH using systematic land-based counts;
3) To estimate abundance of EAH using multi-year capture-recapture analysis, and single-year multi-point capture-recapture analysis; and
4) To undertake a review and assessment of management actions and their influence on recovery of EAH including a review of the threats and the current status of this population under the Environment Protection and Biodiversity Conservation Act (1999) (EPBC Act) and Threatened Species Listing under this Act.
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1.5.3 Thesis outline and contributions by others This thesis consists of a series of related but standalone chapters of work addressing the four aims identified above. It is presented as a series of manuscripts that are at various stages of publication, including several that have already been published. Due to this, there is some repetition of information among chapters. This has been reduced wherever possible, including the combining of all references into a single list at the end of the thesis. General introduction and discussion/conclusions chapters that place the work into a coherent context with a single over-arching focus are also provided. Each chapter builds on the research of those before, and so the discussion in the final chapter covers all findings of this thesis. A brief description of each chapter follows.
Chapter 1 Provides a general introduction and background material on humpback whale biology, ecology, describes the impacts of whaling, and outlines the population structure of humpback whales in the South Pacific Ocean.
This chapter was written by David Paton. Peter Baverstock and Peter Harrison commented on any early draft as part of Paton’s literature review undertaken to enter the PhD course at Southern Cross University (SCU). Simon Childerhouse and Lyndon Brooks provided constructive comment on the draft and Lesley Douglas provided assistance with formatting and layout.
Chapter 2 Discusses the general methodological approaches, and outlines the permits and ethics approvals for the research activities undertaken to inform this thesis.
This chapter was written by David Paton with parts drawn from the following data Chapters: Chapter 3; Chapter 4; Chapter 5; and Chapter 6. Please see below for acknowledgements of contributors to these. Simon Childerhouse, Lyndon Brooks and Peter Baverstock provided constructive comment on the draft and Lesley Douglas provided assistance with formatting and layout.
Chapter 3 The first of five data chapters, this chapter reviews the migratory interchange of SHH based on Discovery mark data, including previously unpublished data. This chapter complements
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other data including: satellite tag; photo-identification; genetic and song data in order to assist in the assessment of humpback whale population structure and migratory interchange.
A previous version of this chapter was presented as a paper at the IWC intercessional meeting in Hobart undertaking a CASH (Paton and Clapham (2006). An assessment of Southern Hemisphere humpback whale population structure and migratory interchange based on Discovery mark data. Unpublished IWC paper SC/60/SH2). While this paper was not formally published, it was discussed in detail at the IWC meeting and was used to explore and develop models of population structure.
This chapter was written by David Paton. Simon Childerhouse, Lyndon Brooks and Peter Baverstock provided constructive comment on the draft and Lesley Douglas provided assistance with formatting and layout. Phil Clapham provided advice on sourcing data. Discovery mark figures were produced with the assistance of Greg Luker, SCU.
Chapter 4 A data chapter that estimates the population growth rate of EAH from systematic land-based counts at Cape Byron over a seven-year period between 1998 and 2004.
This chapter is based on a paper presented to the IWC intercessional meeting in Hobart to undertake a CASH (Paton and Kniest (2006). Cape Byron humpback whale surveys, Eastern Australia, 1998 to 2004. Analysis of data collected during humpback whale sighting surveys at Cape Byron, Eastern Australia, 1998 to 2004. Unpublished IWC paper SC/A06/HW35). A manuscript with minor revisions from that presented in Hobart was published as Paton and Kniest (2011). Population growth of Australian East Coast humpback whales, observed from Cape Byron, 1998 to 2004. Journal of Cetacean Research and Management Special Issue 3 ‘Humpback Whales: Status in the Southern Hemisphere’: 261-268.
This chapter is based on a paper written by David Paton in conjunction with Eric Kniest. The original concept and the survey design for this chapter was that of David Paton, data collection and analysis, interpretation and writing of the manuscript was undertaken with input from Eric Kniest. Kniest developed the real-time whale positioning and tracking software ‘Cyclopes’, which was developed for the Cape Byron Whale Research Project (CBWRP) and used in the collection of the data for this chapter.
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Chapter 5 A data chapter that estimates the abundance of EAH in 2005 using a single-year, multi-point sampling photo-identification capture-recapture analysis and a multi-year single point photo-identification capture-recapture analysis. This chapter is based on two papers presented to the IWC Scientific Committee.
The first paper was presented at the IWC intercessional meeting in Hobart to a CASH (Paton DA, Brooks L, Burns D, Franklin T, Franklin W, Harrison P, Baverstock P (2006) First abundance estimate of east coast Australian humpback whales (Megaptera novaeangliae) utilising mark-recapture analysis and multi-point sampling. Unpublished IWC paper SC/A06/HW32). A manuscript with revisions from that presented in Hobart has been published as Paton DA, Brooks L, Burns D, Franklin T, Franklin W, Harrison P, Baverstock P (2011). Abundance of East Coast Australian humpback whales (Megaptera novaeangliae) in 2005 estimated using multi-point sampling and capture-recapture analysis. Journal of Cetacean Research and Management Special Issue 3 ‘Humpback Whales: Status in the Southern Hemisphere’: 253-259. The original concept for this paper was developed by David Paton. Paton also undertook all data collection associated with the Cape Byron Whale Research Project (CBWRP) during the 2005 field season. Data collected by the Ballina Whale Research Project was coordinated by Dan Burns. Data collected by the Oceania Project was coordinated by Trish Franklin and Wally Franklin. Data analysis was shared equally between David Paton, Dan Burns and Trish Franklin. Statistical analysis was undertaken by David Paton with the assistance of Lyndon Brooks and Dan Burns. Interpretation of data was led by David Paton with the assistance of Lyndon Brooks, Dan Burns, Trish Franklin and Wally Franklin. The writing of the manuscript was led by David Paton with assistance/review from Lyndon Brooks, Dan Burns, Trish Franklin, Wally Franklin, Peter Baverstock and Peter Harrison.
The second paper was presented to the Scientific Committee of the IWC in 2009 and appears as Paton D, Brooks L, Burns D, Kniest E, Harrison P, Baverstock P (2009). Abundance estimate of Australian east coast humpback whales (Group E1) in 2005 using multi-year photo-identification data and capture-recapture analysis, Unpublished IWC paper SC/61/SH10.
The original concept for this paper was developed by David Paton who also led and coordinated the data collection associated with the Cape Byron Whale Research Project
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CBWRP) between 1995 and 2005. Dan Burns assisted with the data collection between 2002 and 2004. Most of the data analysis was undertaken by David Paton, with the assistance of Dan Burns and Greg Gorman. David Paton undertook the analysis with support from Lyndon Brooks. Interpretation of data was led by David Paton with the assistance of Lyndon Brooks. The writing of the manuscript was led by David Paton with support from Lyndon Brooks, Dan Burns, Peter Baverstock and Peter Harrison.
Chapter 6 A data chapter that reviews and assesses the conservation status of EAH including a review of the threats and the current status of this population under the EPBC Act.
This chapter is based on the draft Conservation Management Plan (CMP) for humpback whales in Australian waters that David Paton co-authored in 2013 with Simon Childerhouse and Melinda Rekdahl for the Department of Sustainability, Environment, Water, Population and Communities (SEWPAC) (Childerhouse et al. 2013). Any sections of the CMP not originally written by Paton have been completely rewritten by him for this thesis. The assessment of the current status of the EAH population against the threatened species criteria under the EPBC Act undertaken in this chapter was not part of the draft CMP submitted to SEWPAC and represents original work by Paton. Simon Childerhouse, Lyndon Brooks and Peter Baverstock provided constructive comment on the draft and Lesley Douglas provided assistance with formatting and layout.
Chapter 7 A general discussion and synthesis plus recommendations for future research. This chapter places this thesis into context by discussing the major results in relation to the current understanding of the recovery and movement patterns of the EAH population and the management actions for their long-term survival. All writing, ideas and content is that of David Paton. Simon Childerhouse, Lyndon Brooks and Peter Baverstock provided constructive comment on the draft and Lesley Douglas provided assistance with formatting and layout.
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CHAPTER 2 METHODOLOGICAL APPROACH
2.1 INTRODUCTION
As this thesis consists of a series of related but standalone papers, each chapter contains its own methods section. This chapter provides an overview of the general methods used as well as the permits and ethics approvals obtained for activities undertaken as part of the research contributing to this thesis.
This chapter focuses on the methodological approach undertaken for the Cape Byron Whale Research Project (CBWRP). This project is the primary data collection process for Chapter 4 ‘Population growth of Australian East Coast humpback whales, observed from Cape Byron, 1998 to 2004’ and the multi-year photo-identification study component of Chapter 5 ‘Abundance of East Coast Australian humpback whales (Megaptera novaeangliae) estimated using multi-point single-year (2005) sampling and capture-recapture analysis, and multi-year single-point sampling and capture-recapture analysis (1999-2005)’. It was also one of three projects that contributed data to the multi-point sampling research outlined in Chapter 5. The methodological approach for the other data chapters (Chapter 3 ‘An assessment of Southern Hemisphere humpback whale population structure and migratory interchange based on Discovery mark data’ and Chapter 6 ‘Threats and status of East Australian Humpback whales’) are also outlined.
2.1.1 Cape Byron Whale Research Project The CBWRP was initiated by the author in 1995 and incorporated land- and vessel-based surveys from 1995 until 2005. The CBWRP was supported by the New South Wales National Parks and Wildlife Service (where the author was employed as District Operations Manager between 1995 and 2000), Southern Cross University (SCU – where the author was the Director of the Southern Cross Centre for Whale Research between 2000 and 2002), University of Newcastle, and Blue Planet Marine (a Proprietary Limited Company specialising in marine megafauna research and monitoring, established by the author in 2002 and managed by him as the current Managing Director).
The primary focus of the CBWRP was to investigate key aspects of the dynamics of the population of humpback whales migrating along the east coast of Australia including;
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population recovery rates and estimates of abundance. Additional data were collected, including the recording of movement patterns of whales off Cape Byron, testing new real- time acoustic monitoring and tracking equipment (Dr M. Noad – University of Queensland) and the collection of sloughed skin samples. These data are not discussed as they are not the focus of this thesis. The genetic studies undertaken on the sloughed skin samples are reported in ‘Anderson, M. 2013. Genetic connectivity within eastern Australian humpback whales and their relationship to adjacent South Pacific and Indian Ocean stocks.’ PhD thesis, SCU.
In addition, the CBWRP was the catalyst for the development of a research tool ‘Cyclopes’ by Dr Eric Kniest from the University of Newcastle (now known as ‘Vadar’ – see http://cyclops-tracker.com/).
2.1.2 Study site Cape Byron is located at the most easterly point on the Australian mainland (28°38’S, 153°38’E). This location provides an opportunity to study humpback whales during their annual migration along the east coast of Australia from their feeding ground in the Antarctic to the putative breeding grounds within the Great Barrier Reef. Off northern New South Wales (NSW) and Southeastern Queensland (Qld) the continental shelf narrows resulting in a high percentage (96%) of the migrating population of humpback whales to be within 10 km of the coast between Cape Byron and Cape Morton (Bryden 1985). Surveys (land- and boat-based) were undertaken from Cape Byron from 1995-2004. Due to logistical issues the 2005 survey was undertaken from Skinner’s Headland (28°49’34”S, 153° 36’25”E), 21 km south of Cape Byron (Figure 2.1).
The study area extended from Ballina (28°52’29”S, 153° 35’07”E) in the south to Brunswick Heads (28°32’14”S, 153° 33’23”E) in the north. Vessel surveys extended as far as 15 nautical miles (approximately 28 km) offshore, however the bulk of fieldwork was conducted within 10 km of the coast.
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Brunswick Heads
Figure 2.1: Study site for the Cape Byron Whale Research Project (Cape Byron). In addition the location of the study site for the Ballina Whale Research Project (Ballina) and The Oceania Project (Hervey Bay) are also shown. (Figure produced by Greg Luker, SCU).
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2.1.3 Survey timing and duration The CBWRP monitored humpback whales migrating along the east coast of Australia during the annual northern migration. The timing for the CBWRP was based upon historical whaling data collected at the Byron Bay whaling station, which operated between 1954 and 1962 (Chittleborough, 1965). During this period 1,146 whales (primarily humpback whales) were taken near Byron Bay (Chittleborough, 1965). The survey period was chosen to coincide with the peak of the catches at the whaling station during the northern migration as it is assumed that this peak catch related to the peak in numbers of the northern migration. Surveys were usually a 16-day period undertaken during the peak of the migration (that is, last week of June and first week of July). However, during 2002 and 2005 the survey period was extended. The 2002 survey was extended to five weeks in order to confirm if the peak of the northern migration was still consistent with that recorded by Chittleborough (based on whaling data) and would be captured within the normal 16-day annual survey. The 2005 survey was extended to a ten-week survey in order to allow increased sampling effort to assess the abundance of east Australian humpback whales (EAH) using multi-point sampling and capture-recapture analysis. Table 2.1 shows the duration of the annual survey.
Table 2.1: Duration of annual Cape Byron Whale Research Project surveys.
Year Survey dates Survey period Comments 1995 26 June – 9 July 16 days 1996 24 June – 7 July 16 days 1997 23 June – 6 July 16 days 1998 20 June - 5 July 16 days 1999 19- 20 June, 30 14 days June – 11 July 2000 24 June – 9 July 14 days 2001 23 June – 8July 16 days 2002 17 June – 20 July 34 days The 2002 survey was extended to confirm if the peak of the northern migration was still consistent with that recorded by Chittleborough (1965) 2003 21 June – 6 July 16 days 2004 26 June – 11 July 16 days
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Year Survey dates Survey period Comments 2005 4 June – 12 69 days 2005 survey was extended to a ten-week survey to allow increased sampling October effort to undertake the multi-point and capture-recapture assessment of abundance
2.1.4 Land-based survey Land-based surveys were undertaken from a location (28°38’19”S, 153°38’10”E) ca. 200 m from the most easterly point on Cape Byron from 1995 - 1998. This location has an altitude of 83 m and unobstructed visibility from the south-southeast to the north-northeast (190°– 346°). For the 1999 - 2004 surveys the CBWRP relocated to a location on the upper balcony of the Cape Byron Lighthouse. This location (28°38’19”S, 153°38’11”E) is 173 m from the original land-based survey location and is 33 m higher (total height is 116 m above sea level). The new survey location had a slightly better outlook (south-southeast to the north- northwest) and access to a reliable power supply for operating a computer. It also provided shelter during inclement weather and improved accuracy for distance determination due to the increased altitude. The 2005 survey was undertaken from Skinner’s Headland (28°49’34”S, 153° 36’25”E), 21 km south of Cape Byron. This move was primarily related to logistical issues associated with running an extended project from Cape Byron. It also allowed a comparative assessment of land-based data collected by the Ballina Whale Research Project (BWRP) during the southern migration, which was operated from this location.
A software package named Vadar (previously Cyclopes) was developed specifically for the CBWRP by staff and students from the University of Newcastle, Australia. Vadar provided more reliable tracking of marine mammals and vessels. This real-time tracking system used an electronic theodolite interfaced to a laptop computer. The theodolite was used to acquire the location of a pod of whales by measuring the horizontal and vertical angles to the pod, which were sent directly to the computer. Vadar then calculated the position of the pod correcting for tides, earth curvature and refraction. The program determined which pod was observed and plotted its position on a map shown on the computer screen. Vadar also has the capability to record information regarding the pod’s make up, activity, speed, course, distance, direction and time of observation (see Figure 2.2 for a screen shot for one day of Vadar data for the CBWRP) (Kniest and Paton 2000, 2001a,b).
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Figure 2.2: Vadar screen shot for 5 July 2002, CBWRP.
Observers used both the naked eye and binoculars (7×50 Tasco compass binoculars and 10×50 Nikon binoculars) to detect whales. Once pods were sighted, a theodolite operator (who was in addition to the dedicated observers) using a Leica TC1105 theodolite (or similar) would take fixes on the location of the pod and track movement of it while within the field of view of the land station. When additional personnel were available a person was dedicated to operating Vadar and assisting the research vessel to locate pods. At all times at least one observer was scanning for new pods.
Records of effort and weather were kept during all observation periods. Weather information including wind speed and direction, cloud cover, sea state (Beaufort), swell, visibility (estimated in km) and any other factors such as smoke haze, were recorded using Vadar’s weather recording function. In addition Cape Byron headland has a meteorological station with detailed weather information available for the site from the Australian Bureau of Meteorology.
When pods were first observed and an experienced observer confirmed the species, the observers would estimate pod composition and continually track each pod as it approached
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the Cape from the south. The pod composition would be adjusted (and confirmed by an experienced observer) when necessary. Careful notes were taken when pods split or joined, or there was a sudden change in behaviour. Pod composition was confirmed by the research vessel when the vessel intercepted the pod. The research vessel, under normal operating protocols, operated north of the Cape so as not to potentially disturb the movements of whales prior to passing the Cape.
Observers would monitor a pod’s activity and direct the theodolite operator to the surfacing of pods. Where possible one event out of each surfacing cycle would be fixed using Vadar in order to monitor the movement pattern of the pod. Once a number of sightings of the pod were recorded, the program was able to predict the direction and speed of travel and any changes in course or speed. These data were plotted in real time on the computer screen showing the trackline of pods passing the land station. The program was extremely useful in eliminating duplicate counts of the same pod especially when pods were located close together or when a pod was lost for a period of time.
2.1.5 Vessel-based survey Vessel-based surveys were conducted from Cape Byron for the years 1995-2004. The 2005 surveys were undertaken in the same survey area, however the research vessel was launched from Ballina and not Cape Byron. The primary vessels used were a 5.8 m rigid-hulled inflatable, Manta and a 5.4 m centre console, Beluga. However a number of other vessels were also used. They were all between 5 and 6 m in length and either a centre console or forward control with an outboard engine(s).
Vessel-based surveys were conducted each day, weather permitting, during the annual survey period. Vessel-based surveys were conducted in conjunction with the land-based surveys, where the land-based survey team would direct the vessel by radio to the nearest pod to the research vessel, irrespective of size or activity of the pod.
The vessel survey team usually was made up of a team of four researchers (Master, photographer, data recorder and sloughed skin collector). Survey effort and data collection commenced as soon as the vessel was launched at Cape Byron or once it crossed the Richmond River bar at Ballina.
The primary focus of the vessel survey team was to collect fluke photographs as a means of identifying individual whales. Data collected for each pod encounter included: unique pod
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number; encounter time; location (waypoints in Latitude and Longitude); water depth; pod composition and size (including the number of calves present); behaviour including direction of travel; description of photographs taken by frame number; sloughed skin collected and weather conditions (including Beaufort sea state; wind speed and direction; swell height and direction; cloud cover (oktas); precipitation and visibility.
2.1.6 Land-based data analysis For each day the total number of humpback whales migrating past Cape Byron was determined following assessment of the day’s Vadar job file. All sight data were converted to a standard 10-hour day, consistent with the methodology used in other migratory humpback whale surveys (Brown 1996; Bryden et al. 1996; Findlay and Best 1996b; Paterson et al. 2004; Noad et al. 2011a). The standard survey period was 9.5 hours, therefore the sighting rate was scaled pro-rata to a 10-hour survey period. Due to the expansive field of view from the land station (over 180°), only pods that had crossed a line due east of the Cape during the survey period were included in the analysis. The time each pod passed the line extending east of the Cape was calculated by projecting from the pod’s closest observed position along a line representing its mean course and speed. These pods were included in the analysis if they were determined to have passed east of the Cape during the survey period. Only humpback whales observed travelling in a northerly direction were included in the analysis.
In order to avoid double counts or missing whales when pods split into separate groups or when other whales would join a previously tracked pod, the number of whales was only counted in the initial pod. After an affiliation or disaffiliation of a pod occurred, the new pods formed would be assigned new names. During analysis these pods would have the number of whales in the pod set to zero (although the pod composition is still noted). For example if pod ‘D’ (size = 1) joined pod ‘H’ (size = 2), the new pod formed would be called ‘H/D’ with composition noted as 3 but the pod size is assumed to be zero for the sake of determining whale counts; and the new pod is not included in the count as an extra pod.
Determining which days should be excluded from the analysis due to adverse weather can be subjective. For the purposes of this analysis, the following protocol was used for the exclusion of days: (1) days with a mean sea state greater than Beaufort 3 and/or mean visibility less than 15 km for extended periods; and (2) days on which fewer than five hours of survey were conducted.
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2.1.7 Photo-identification Fluke photographs were taken as a means to identify individual humpback whales based on unique pigmentation patterns and scarring on the ventral surface of flukes, together with serration patterns along the trailing edge (see Katona et al. 1979). Individual fluke identification is used in order to provide data to estimate population abundance (see Chapter 5). Records of each frame number and individual within a pod photographed were recorded. Blank images were taken to confirm a break between pods and aid in analysis. Images between 1995 and 2002 were taken using slide film and images from 2003-2005 were taken using digital cameras. All photos were taken using either a Canon EOS camera and lens or a Nikon camera and lens. Canon cameras used included either EOS 1, 5, 10D and 20D fitted with either a 300 mm F2.8 L series lens or a 100-400 mm F3.5-5.3 L series lens. The Nikon camera used was a D100 digital camera with a 70-200 mm F2.8 L series lens with a 1.4X converter. All selected photo identification images on slide film were scanned and saved as .tiff files at an approximate file size of 28 MB. All digital images were shot on the ‘large’ and ‘fine’ .jpeg settings. All digital images were archived as .tiff files (at a file size of approximately 21 MB) before being analysed.
2.1.8 Photographic data analysis Following the completion of field work, all photographic images for each pod were reviewed in conjunction with the vessel field records. For each pod the best fluke identification photograph(s) were selected for each individual in the pod. All slide photographs were viewed on a light table using a loop. Selected identification images were then scanned. All images (including images from slide film and from digital cameras) were then reviewed digitally using Photoshop CS software. Each original image was saved as a .tiff file and a working copy was saved as a .jpeg file (900x600 pixels @300 dpi ~ 300 to 500 kb). Working copy images were adjusted for contrast if this was poor using the ‘Shadows/Highlights’ option within Photoshop CS and then rotated so the tips of the fluke, where possible, were horizontal with the top of the frame and cropped to a common 3×2 pixel ratio as high quality .jpeg digital files so the images filled the frame as much as possible. Note the ‘Shadows/Highlights’ option within Photoshop CS does not modify the image data whereas other options to adjust contrast may affect the original data, which is not desirable (Adobe Systems Incorporated 2005). These images were then entered into the CBWRP Fluke Identification Database and given a unique number.
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For the purpose of calculating the abundance estimates associated with Chapter 5, all images in the CBWRP Fluke Identification Database were then assessed for image quality based on a number of variables using the SPLASH quality criteria (see http://www.cascadiaresearch.org/splash/splash.htm). These include:
Exposure – light flukes; Exposure – dark flukes; Fluke angle; Focus/sharpness; Lateral angle; and Proportion visible. In some cases where a single fluke was not available, which showed all the distinguishing features for that animal (that is, the angle was poor or the fluke was partly obscured by water amongst other factors) a number of images may have been selected (that is, composite photos).
All images were entered into a fluke categorisation system developed by Burns (Burns 2010). A stratified matching system developed by Burns was used in this analysis. This system is based on stratifying flukes by different characteristics including percentage black, characteristics of the centre and characteristics of the trailing edge of the fluke for each identification photograph. This system was used to reduce the number of comparisons required in the matching process. All matches found were reviewed and confirmed by at least two researchers.
Burns’ stratified matching system reduces the likelihood of false negatives in matches. As a consequence, however, the system has the potential to yield false positive matches. Hence the requirement for all ‘positive’ matches to be reviewed and confirmed by two experienced researchers.
All images were then reconciled within and between years within the Cape Byron dataset.
2.1.9 Sampling permits and ethics approval Samples from Byron Bay were collected in Commonwealth waters under scientific research permits #96/00853-P1998/057 and #E2001/0005 issued by Environment Australia and the Department of Environment and Heritage (now Department of Environment). Samples
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collected within State waters were under permits #1701 and #S10403. All sampling was undertaken with the approval of the SCU Animal Ethics Committee.
2.1.10 Collaborative research Following a preliminary analysis of the mark recapture data for the CBWRP and a review of the current population estimate for the population of whales migrating along the east coast of Australia, it was determined that in order to increase the precision of the analysis, a larger sample size would be required during the 2005 sampling season. The 2005 CBWRP field season was, therefore, increased from 16 days to ten weeks. Due to logistical and resource limitation as well as a population increasing annually at over 10%, it was also essential to enter into a collaborative approach for data collection.
Chapter 5 of this thesis ‘Abundance of East Coast Australian humpback whales (Megaptera novaeangliae) estimated using multi-point single-year (2005) sampling and capture- recapture analysis, and multi-year single-point sampling and capture-recapture analysis (1999-2005)’ includes photographic data collected by other researchers from the Southern Cross Whale Research Centre. This data collaboration for the 2005 field season included the BWRP and The Oceania Project (TOP).
The BWRP (coordinated by Dan Burns) is based at Ballina located approximately 30 km south of Cape Byron and included land- and vessel-based surveys of the southern migration of humpback whales. The methods used for these surveys were consistent with those used for the CBWRP (see section 2.1.4 to 2.1.8). Land-based surveys were coordinated from Skinner’s Headland (28°49’34”S, 153° 36’25”E) and vessel-based operations using a 6.1 m centre console vessel were coordinated out of the Richmond River at Ballina. The survey area was between Lennox Head and Evans Head and 15 nm seaward. Survey dates for the 2005 field season were 17th August to the 4th November 2005. During this period a total of 288 photographs were collected using a Nikon D100 digital camera with a 70-200 mm lens with a 1.4X converter.
TOP, coordinated by Trish and Wally Franklin, is a long-term vessel-based study of humpback whales in Hervey Bay, Qld (approximately 520 km north of Byron Bay – 25° 00’S, 153° 00‘E). This project focuses on animals that enter Hervey Bay, a shallow sheltered bay close to the western shore of Fraser Island, during the southern migration. It is not supported by a land-based team. This team uses a 12 m powered live aboard catamaran to undertake the surveys. The survey period for 2005 was 7th August to the 14th October. During
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this period a total of 391 photographs were collected using a Canon EOS 20D, 100-300 mm lens F3.5-5.6.
2.1.11 Sampling permits and ethics approval The BWRP was undertaken in Commonwealth waters under scientific research permits #E2001/0005 issued by Environment Australia and the Department of Environment and Heritage (now Department of Environment). BWRP research within State waters was conducted under permits #1701 and #S10403. Research undertaken by TOP was conducted under State permits #C5/001191/SAA (Queensland Parks and Wildlife Service), #MP2000/031 (State Marine Park), and #WITK01192903 (Environmental Protection Agency, Queensland). All sampling was undertaken with the approval of the SCU Animal Ethics Committee.
2.1.12 Discovery mark data A detailed literature review was undertaken for all available data associated with Discovery marking of humpback whales in the Southern Hemisphere (SH). Primary data sources included:
Published and unpublished documents containing Discovery mark data and/or analyses of these (Appendix IV provides a list of these documents); International Marking Scheme (IMS) Discovery marking database provided by the IWC; Soviet Marking Scheme (SMS) Discovery marking data (Ivashin 1973); Original Discovery marking logbooks compiled by Dr William Dawbin for marking activities he coordinated in Australia, New Zealand (NZ) and the Oceania region; and Additional, previously unreported data from the Soviet Union.
Data were reviewed and compiled into a new, Revised Discovery Marking Database (RDMD) with reference to the appropriate marking scheme with which the data were associated. All duplicated records were removed and discrepancies in data were assessed and omitted or noted in the RDMD as appropriate. The accuracy of data was validated insofar as possible, especially regarding Soviet data, which were falsified in order to hide illegal whaling conducted last century. Further refinement of data was undertaken as detailed in section 3.4.
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An analysis of the RDMD was undertaken in order to plot the connections between tropical breeding areas and feeding grounds in the Antarctic, Breeding Stocks, and to show general patterns of movements of individual whales. Data were also analysed in order to determine time between marking and capture as well as longitudinal movements.
No research permits or animal ethic approvals were required for this research. However, approval was given by Dr Bill Dawbin’s family (Bruce Dawbin pers. comm.) to access his original logbooks and associated data, now archived at the Mitchell Library, Sydney. Approval to access the IWC Discovery Mark database was obtained and access to the IWC Discovery Mark database was provided with the assistance of Cherry Allison.
2.1.13 Management and assessment under the EPBC Act A critical review was undertaken of relevant scientific literature, international and Australian legislation and agreements, and Government management plans for humpback whales in Australian waters. An assessment and review of the conservation status of EAH was carried out, including a critical evaluation of the threats and current status of this population under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). In order to place the EAH population into context, some management consideration of the other populations of humpback whales within Australian waters was conducted. In addition, a critical evaluation of the current status of the EAH population against the threatened species criteria under the EPBC Act was performed in order to assess the appropriateness of its existing listing as ‘vulnerable’. Further details of the methods undertaken are outlined in section 6.4.
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CHAPTER 3 AN ASSESSMENT OF SOUTHERN HEMISPHERE HUMPBACK WHALE POPULATION STRUCTURE AND MIGRATORY INTERCHANGE BASED ON DISCOVERY MARK DATA1
3.1 ABSTRACT
In general, the migratory interchange among Southern Hemisphere humpback whale (SHH) populations is not well understood. This presents a potential challenge for the accurate assessment of stock structure and, perhaps most importantly, makes it difficult to estimate pre-exploitation size of these populations accurately and therefore the present status of their recovery. This will limit the effectiveness of ongoing management to ensure the recovery of these depleted SHH populations. Discovery marks are the only source of historical information that can be used elucidate the historic stock structure of SHH. While there are some limitations with this approach (for example, unequal deployment and recovery effort, non-reporting of recoveries by illegal Soviet whaling), these can be accounted for to some degree when drawing conclusions from this data source.
Discovery marks have confirmed links between Breeding Stocks C, D and E and their putative feeding grounds in the Antarctic to the south of the Breeding grounds. Discovery mark data indicate that SHH do form relatively discrete groups through strong linkages between breeding grounds within the longitudinal boundaries of the feeding areas. There is
1 A previous version of this paper was presented at the IWC intercessional meeting in Hobart undertaking a Comprehensive Assessment of Southern Hemisphere Humpback Whales (Paton and Clapham (2006). An assessment of Southern Hemisphere humpback whale population structure and migratory interchange based on Discovery mark data. Unpublished IWC paper SC/60/SH2). While this paper was not formally published, it was discussed in detail at the IWC meeting and was used to explore and develop models of population structure. A statement of contributions to this paper is included in section 1.5.3.
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a relatively low incidence of large-scale movement between feeding areas, perhaps with the exception of Breeding Stock E, which appears to have a more broadly dispersed system of interchange between multiple breeding and several feeding areas.
The dispersal of whales from Breeding Stock E has a wide distribution beyond what was originally considered to be the putative feeding areas in Area V. That is, extending from Antarctic Area IV to Area I covering a range of approximately 175° of longitude (nearly half the globe). Discovery mark data have documented a much wider distribution of whales from Breeding Stock E than was previously known. Further research (including satellite tracking, further genetic and photo-identification matching of all available data) is required in order to confirm the significance of these movements but these data are consistent with the Discovery mark data in that there is a low level of interchange.
3.2 INTRODUCTION
Humpback whales undertake seasonal migrations from their breeding grounds at low latitudes to feeding areas at mid to high latitudes (Dawbin 1966). The relationship and connections between these breeding and feeding grounds for most SHH populations are not well understood. This presents a potential challenge for the accurate assessment of stock structure and could limit the effectiveness of ongoing management to ensure the recovery of the depleted SHH population.
The IWC declared in 1982 a cessation of all commercial whaling (commonly known as ‘the moratorium’), which came into effect from 1986. At the same time they committed to undertake a ‘Comprehensive Assessment’ of all whale stocks (Donovan 1989). The ‘Comprehensive Assessment’ involves an in-depth evaluation of the status of most whale stocks. It includes examination of current population size, recent population trends, carrying capacity, productivity and other factors. Other key components include a knowledge of population structure and an evaluation of status. This latter issue requires knowledge of the pre-exploitation abundance of the population (Gales et al. 2011).
This chapter reviews the migratory interchange of SHH based on Discovery mark data, including previously unpublished and unavailable data. The specific objective of this chapter is to review Discovery mark data in order to assist clarification of stock structure of Breeding Stock E, and the potential for interchange with other populations within the Southern Hemisphere (SH).
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The analysis in this chapter complements that used for other data including: satellite tags; photo-identification; genetics and acoustics, and so furthers the assessment of SHH population structure and migratory interchange. While this chapter reviews information on all SHH Discovery marking data, it focuses on data associated with east Australia humpback whales (EAH) including those from feeding stocks IV and V, and breeding stocks D and E.
3.2.1 Background
The management of humpback whales in the SH has long been based on a system of geographically designated, IWC defined management units (called Areas) relating to assumed whale stocks (Donovan 1991). Hjort et al. (1932) first proposed dividing the Antarctic into broad whaling management areas based on Antarctic catch data for southern stocks of baleen whales (based mainly on blue and fin whales). These areas (defined as Areas I through V) were first formally recognised in 1937 as management regions for which whaling catch limits were issued or which were closed to whaling (also known as Sanctuary areas).
A Discovery marking research programme was first trialled in 1924 (see detailed discussion in section 3.3) to provide information that could be used to improve the management of whale stocks, especially regarding stock structure (Mackintosh 1942, 1965; Brown 1977; Dawbin 1964). Following preliminary results from Discovery marking, Mackintosh (1942) proposed a further refinement to the Antarctic management areas and used the phrase ‘Group’ to denote ‘a concentration of whales occupying a tropical breeding ground and a feeding area with limited or no mixing with adjacent concentrations of whales’. Hjort et al. (1932) originally identified five distinct Areas within the SH with each Area containing a Group of humpback whales that generally moved north and south between breeding and feeding areas. These Areas were numbered I – V and the whale groups within each of these five Areas were known as Group I – Group V. Mackintosh (1965) expanded these five Groups to six following further review of Discovery mark data (Figure 3.1). Although these definitions of Antarctic management units had been used extensively in the scientific literature since their inception in 1965 and the IWC had been using these Areas as management units for SH baleen whales for some time, Donovan (1991), states that the IWC did not officially adopt these stock boundaries until the 1974/75 season.
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Figure 3.1: Boundaries of six Southern Hemisphere whaling areas adopted by the IWC. Adapted from Paterson (2001).
These six Antarctic Areas are still used in the IWC today but with the advent of new research techniques, including genetic analysis, the IWC (1998) recommended additional stock divisions. Specifically, the original Areas only corresponded to Antarctic feeding grounds and until 1998 there was no formal description or divisions of tropical breeding areas. In 1998, the IWC identified seven different breeding stocks or Groups. To differentiate these Groups from those originally proposed by Mackintosh, the IWC identified these Groups by calling them Breeding Stocks A-G. Since that time, analysis of stock structure data has continued and further Breeding Group sub-structuring has been proposed (for example, Group E divided into in E(1), E(2) and E(3) – Anonymous 2003a).
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There is considerable variation in the population structure of humpback whale stocks globally. Due to geographically confined areas of high productivity in the Northern Hemisphere (NH), humpback whale populations there form discrete feeding aggregations with maternally directed site fidelity to each feeding region and low rates or interchange between regions (Palsbøll et al. 1995; Baker et al. 1998; Calambokidis et al. 2001). Unlike in the NH, SHH feed in circumpolar waters surrounding the Antarctic continent with no land masses acting as physical barriers between whale stocks. Until recently there has been limited data on the movement of humpback whales within their SH feeding areas. Drawing a parallel with intensively studied humpback whale populations in the North Atlantic and North Pacific Oceans, SHH were thought likely to form feeding aggregations, with high rates of return to specific feeding areas. It was assumed that SHH, like the NH humpback whale populations, would exhibit relatively low incidence of large-scale movement between IWC management units (Areas) (Katona and Beard 1990; Calambokidis et al. 2001; Stevick, 2005). This chapter provides evidence which demonstrates that SHH populations show a much higher rate of dispersal between IWC management units than their NH counterparts.
3.3 DISCOVERY MARKING
Individually identified animals can be used to learn about a wide range of biological and ecological characteristics. The ability to track an individual through space and time allows for the monitoring of movement patterns (including migration and dispersal), behaviour, and determination of age, growth rate, breeding success and population size in a wide range of species (Emmel 1976; McGregor and Peake 1998). There are a huge range of methods available to individually identify animals and these can be broadly grouped into two categories: natural marks (such as fluke patterns, scarring, genotyping) and artificial marks (including bands, tags, brands, microchips). The ability to identify individual animals by distinctive natural markings and/or genetic markers is a technique now used widely and is generally considered to be less invasive (Jurasz and Jurasz 1979; Katona and Whitehead 1981; Katona et al. 1979). However, prior to the use of natural marks, artificial marks were almost exclusively used.
In 1924, a method of marking whales was trialled that lead to the development of the Discovery mark. The marks consisted of a solid metal spike approximately 23 cm long fitted with a leaden ballistic head. These were designed to be fired from a modified 12 gauge shotgun. The principle was that they would completely penetrate the blubber and lodge in
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the muscle layer beneath with no part of the mark protruding from the whale. The only way they could be recovered was during processing associated with whaling activities. That is, when a dead whale was cut up and the blubber rendered down, the mark would be found and recovered. Each mark was engraved with a unique serial number and an address for return (Figure 3.2 and Figure 3.3). In some instances, Discovery marks were also fitted with streamers that would protrude from the whale once successfully marked. These streamers were used to confirm if a whale was successfully marked and to avoid double marking.
These marks were relatively rudimentary in nature in that the only data that could be obtained were data from the marking event (such as date, location, behaviour) and the capture event (the same data as for marking but with the addition of data such as reproductive state and age, which could be determined during the processing). Obviously, no information was available about the exact movement pattern between the marking and capture locations nor was any new information possible once the whale was killed.
Discovery marking activities were undertaken during dedicated Discovery Marking cruises as well as an adjunct to whaling operations. Discovery marking associated with whaling activities primarily occurred in the feeding grounds and on the migratory corridor of humpback whales where the bulk of the whaling activities occurred. Discovery marking was undertaken during dedicated research expeditions as part of the Discovery Programme in other locations such as Fiji, Tonga, Vanuatu and New Caledonia (Dawbin 1964; Brown 1977).
Figure 3.2: Discovery mark. Photo D. Paton.
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Figure 3.3: Discovery mark engraved with a unique serial number and an address for return. Photo N. Hauser.
Discovery marks were not always recovered during the flensing stage of the processing of a whale during whaling operations. Once a whale was caught, it was brought back to either a land-based whaling station or a factory ship for processing. This involved dismembering a whale on the flensing deck where blubber was removed into long strips and cut into manageable blocks before being fed into high-pressure steam cookers, which extract the oil. If not detected during the flensing process, Discovery marks could be found inside ‘cookers’, which were cleaned out periodically. However Ruud and Oynes (1954) reported that only a third (34%) of Discovery marks placed in cookers by whaling inspectors were recovered, indicating that a high percentage of marks may not have been recorded. When a Discovery mark was found in a cooker it was not possible to attribute the mark recovery with any certainty to any particular whale. Therefore the species, date and location for the recovery of Discovery marks found in a cooker may be inaccurate depending on when the cooker was cleaned out.
3.3.1 Discovery marking schemes
There were two primary whale marking schemes undertaken in the SH. The International Marking Scheme (IMS) coordinated by the Institute of Oceanographic Sciences (formerly the National Institute of Oceanography (U.K.), supported by the IWC and formally part of the Discovery Programme (Rayner 1940)) and the Soviet Marking Scheme (SMS) coordinated by the former USSR. The IMS marked a total of 33,405 whales in the SH between 1932 and 1984 (IWC database) whereas the SMS marked a total of 1,797 whales between 1952 and 1972 in the SH (Ivashin 1973). Details for the total number of whales marked under the SMS (that is, any further marking following 1972) are not available. In
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addition to these major programmes, a number of other smaller Discovery marking schemes, including the Australian Marking Scheme (AMS), were undertaken in the SH (Brown 1956; Chittleborough 1959b; pers. com. C Allison 2006). Although the IMS and the SMS were entirely separate marking programmes (but using similar marking systems), it was believed that there was a sharing of data between the two schemes in relation to the recovery of Discovery marks (Anon. undated – Annex J SC/25/1).
The recovery of these marks provided invaluable information on movement patterns of whales throughout the SH. These Discovery mark returns were recovered from whaling activities throughout the migratory range of humpback whales within the SH (that is, from breeding areas, feeding grounds and migratory corridors). Given the large number of marks put out, the rate of recoveries was considerably lower than expected by scientists of the time. This low level of recoveries occurred concurrently with the observed rapid (and at that time unexplained) decline in whale numbers recorded in the early 1960s. The reason for the decline is now well documented with the Soviet Union undertaking extensive illegal whaling operations in the Antarctic between 1948/49 and 1971/72. Over this period, the Soviets reported killing 133,621 whales when in fact they killed 227,180 (Mikhalev 2000; Clapham et al. 2005, 2009; Ivashchenko et al. 2011). A high proportion of these legally and illegally caught whales were in Areas IV and V. In order to conceal these illegal catches of humpback whales, the USSR did not report many of the Discovery mark return data that they collected (Mikhalev pers. comm.). The recent publication of the true USSR catch data coincided with the release of previously unreported Discovery mark return data by the Soviets. This chapter reviews these new data along with other previously unreported Discovery mark returns and provides the first analysis of how they fit within the existing understanding of SHH population structure.
3.4 METHODOLOGY
A detailed literature review was undertaken for all data associated with Discovery marking of humpback whales in the SH. Primary data sources included:
Published and unpublished documents containing Discovery mark data and/or analyses of these (Appendix IV provides a list of these documents); IMS Discovery marking database provided by the IWC (November 2005); SMS Discovery marking data (Ivashin 1973);
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Original Discovery marking logbooks compiled by Dr William Dawbin for marking activities he coordinated in Australia, New Zealand and the Oceania region. These logbooks form part of the Dawbin collection of material now held by the Mitchell Library in Sydney; and Additional, previously unreported data from the Soviet Union now available in reports to the IWC. Data were reviewed and compiled into a new, Revised Discovery Marking Database (DMD) with reference to the appropriate marking scheme with which the data were associated (that is, the IMS, SMS or other such as the AMS). Of particular importance in this dataset were the records in Dawbin’s Discovery marking logbooks. A previously unknown source of data, these logbooks augmented data in IMS, some of which was previously unreported.
A copy of the IMS Discovery marking database, managed by the IWC, was obtained and sorted by species. The data for humpback whales were then cross referenced against the data compiled from the literature review and additional sources, and all duplicated records were removed. The available data from the SMS were assessed against recent records of illegal catches and misreporting by the Soviets. As, at the time of writing, the full data associated with the SMS were not available, and the existing data were of unknown accuracy and included deliberate falsification (Mikhalev et al. 2009; Ivashchenko 2011), it was decided to not use these data and therefore they have not been included in the analysis for this chapter.
Where new and/or corrected/updated data were available, the Revised DMD was updated to include the new data. Where discrepancies were identified in the data (including discrepancies in relation to species, location and date) an assessment was made as to the validity of the data available. The assessment involved reviewing possible contributing factors for discrepancies in the data. These factors include possible confusion as to the: species of whale from which the mark was recovered; exact date and location due to the mark being found in a cooker (refer section 3.3) and possible falsification of records by the Soviet whaling fleets to hide illegal whaling activities. Where there were remaining issues related to the accuracy of the data, the inconsistencies in the data were identified in the Revised DMD.
For the purposes of this analysis, Discovery marks found in the cooker on factory ships have not been included due to the possibility of the movement of the factory ship from the location
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from where the humpback whale was killed. However, Discovery marks recovered from the cooker of a land-based whaling operation have been included in the analysis of movement data. This is appropriate because although the date of capture of the whale may be inaccurate, the location should be reliable within the accuracy required for this analysis (that is, approximately one degree of latitude and longitude).
Data associated with the date of recovery of Discovery marks found in cookers have not been included in the analysis related to the duration between marking and recovery. When mapping movements of whales, marks returned within a migratory season (that is, within nine months) have been differentiated from longer-term recoveries.
Data from the IMS represents the bulk of data for this analysis. Unfortunately the full data associated with the SMS and the AMS are not accessible. Every effort has been made to validate the accuracy of the data, in particular reports of IMS Discovery mark returns from the Soviet whale fleet. Concerns have been identified as to the potential for inaccuracies in the Soviet data due to the falsification of records. Reports of the IMS Discovery mark return data from the Soviet whaling fleet have been crosschecked where possible against the recently published corrected locational and date data for the Soviet whaling activities in the SH and inconsistent records removed. For the purposes of this analysis only data from the IMS and AMS have been included. Further investigations are required to obtain the full records for the SMS.
An analysis of the Revised DMD was undertaken in order to plot the connections between tropical breeding areas and feeding grounds in the Antarctic; Breeding Stocks and show general patterns of movements of individual whales. Data were also analysed in order to determine time between marking and capture as well as longitudinal movements.
3.5 RESULTS
3.5.1 Overview
A total of 33,405 whales (with a focus on baleen whales and sperm whales) were marked with Discovery marks in the SH as part of the IMS and the AMS between 1932 and 1984. Of these, 5,163 were marks associated with humpback whales that were entered into the Revised DMD for analysis. Figure 3.4 indicates the number of humpback whales marked per year in the SH from available records. The locations of Discovery marking activity
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(including all marking attempts) associated with humpback whales in the SH are indicated in Figure 3.5.
900
800
700
600
500 whales
400 of
300 Number 200
100
0 1932 1937 1942 1947 1952 1957 1962 1967 1972 1977 Year
Figure 3.4: Number of humpback whales Discovery marked per year in the Southern Hemisphere between 1932 and 1984. (n = 5,163).
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D E F C B
A
G
IV V
III VI II I
Figure 3.5: Locations of Discovery marking (including all marking attempts) for humpback whales in the Southern Hemisphere. Breeding Stocks A-G and Antarctic Areas I-VI are shown (n = 5,163). Note: Discovery marking locations have been plotted by one degree of latitude and longitude for summary purposes. Therefore not all 5,163 locations are shown in this figure.
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3.5.2 Success of deployments
Of the 5,163 marks associated with humpback whales, only 3,111 marks were recorded as successful deployments (that is, confirmed hits). Table 3.1 provides a summary of the status of all deployment attempts on humpback whales. Definitions for deployment outcomes are:
1) Invalid, for example, whale believed fatally injured;
2) Fate unknown, for example, after accidental or practice firing or misfires over boat side;
3) Multiple mark, if the same whale is believed hit more than once the final verdict in one of these records will be 9 and 3 in all others;
4) No verdict;
5) Miss;
6) Ricochet;
7) Protruding hit;
8) Possible hit; and
9) Hit (except for multiple tags – see note for multiple mark).
Table 3.1: Reported deployment outcomes from Discovery marking attempts and recovery rates of Discovery marks by deployment status for Southern Hemisphere humpback whales.
Deployment outcome
Invalid unknown Multiple mark verdict No Miss Ricochet Protruding hit hit Possible Hit Total Frequency 0 40 135 62 1220 136 204 255 3,111 5,163 No. 0 1 9 0 5 2 2 2 183 204 recoveries % 0% 2.5% 6.7% 0% 0.4% 1.5% 0.98% 0.88% 5.9% 4% recovered
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3.5.3 Recoveries – in relation to deployment status
Table 3.1 provides a summary of recoveries of Discovery mark deployments in relation to the deployment status of the mark. Details of the definitions of the deployment status are provided in section 3.5.2. Table 3.1 shows that even though a final verdict of a Discovery mark may be recorded as a confirmed miss, or a ricochet, there are a number of recoveries of marks associated with these final verdicts. Clearly incorrect deployment outcomes have been recorded. If only data from confirmed hits are to be used in analysis, then there exists the possibly that some valid data will be excluded. Given the low recovery rates found, this could further reduce an already small data set. The inclusion of data from deployments not confirmed as definite hits adds 21 recoveries. This is a 10% increase over using data from confirmed hits alone.
3.5.4 Deployment effort
The Discovery marking effort by IWC Management Area (including all marking undertaken in the feeding grounds, migratory corridor and breeding grounds) is shown in Table 3.2. Discovery marking effort was non-randomly distributed with the bulk of marks being deployed in Areas IV and V, and the putative breeding areas of Breeding Stocks D and E. A total of 2,885 humpback whales marked within these regions comprising 18% and 10% of all marks were deployed in Areas IV and V respectively and 6% and 58% for breeding grounds for Breeding Stocks D and E respectively. For the purpose of this analysis, the feeding grounds have been defined as waters south of 50° S and the breeding grounds and migratory route as the waters north of this latitude. This definition differs from that used regularly in the literature and while this has only limited biological application, it is a useful and practical division for the exploration of these data.
3.5.5 Investigation of the location of successful deployments and recoveries
Analyses of marks that were recovered by both the deployment location and the recovery location are provided in Table 3.3 and
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Table 3.4. These forms of analysis are important to provide an insight into any potentially significant biases that may be evident in the data relating to non-random sampling during deployments and recoveries. The major feature of this data set is that the bulk of marks were both deployed (65%) and recovered (68%) north of 50⁰ S.
Table 3.2: Number of deployments of Discovery marks by IWC Management Area (south of 50° S) and breeding grounds and migratory corridors (north of 50° S). Note: the longitudinal range of IWC Management Areas and breeding grounds/migratory corridors do not correspond exactly but have been grouped here for convenience.
IWC Area I II III IV V VI Total (%) South of 50° S 61 21 112 569 319 16 1,098 (35%) Corresponding G A C D E F breeding stock North of 50° S 0 6 7 181 1,816 3 2,013 (65%) Total 61 27 119 750 2,135 19 3,111 (100%)
Table 3.3: Number of Discovery marks that were both successfully deployed and subsequently recovered shown by deployment location and IWC Management Area (south of 50° S) and breeding grounds and migratory corridors (north of 50° S). Note: the longitudinal range of IWC Management Areas and breeding grounds/migratory corridors do not correspond exactly but have been grouped here for convenience. Total numbers in this table (n=204) exclude data for marks recovered from the cookers on factory whaling ships and therefore are lower than the total number of marks returned (n=5).
IWC Area I II III IV V VI Total (%) South of 50° S 4 2 7 42 22 1 78 (38%)
Corresponding G A C D E F breeding stock North of 50° S 0 0 0 16 110 0 126 (62%) Total 4 2 7 58 132 1 204 (100%)
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Table 3.4: Number of Discovery marks that were both deployed and subsequently recovered shown by recovery location and IWC Management Area (south of 50° S) and breeding grounds and migratory corridors (north of 50° S). Note: the longitudinal range of IWC Management Areas and breeding grounds/migratory corridors do not correspond exactly but have been grouped here for convenience. Total numbers in this table (n=204) exclude data for marks recovered from the cookers on factory whaling ships and therefore are lower than the total number of marks returned (n=5).
IWC Area I II III IV V VI Total (%) South of 50° S 4 1 5 29 25 1 65 (32%)
Corresponding G A C D E F breeding stock North of 50° S 0 1 2 41 95 0 139 (68%) Total 4 2 7 70 120 1 204 (100%)
Figure 3.6 shows the marking and recovery locations for all SHH from which marks were recovered. It is important to note that the lines connecting the marking and recovery locations as indicated in Figure 3.6, are not a true representation of the whales’ movements between the times of marking and recovery but are provided to indicate the relationship between the two locations.
Table 3.5 shows the number of humpback whales that were recorded as moving between IWC Management Areas and Breeding Stocks between marking and recovery. A total of 19 whales were reported to have moved from the Area in which they were marked into other Management Areas. Of these 19 whales, 18 or 95% moved from the Area where they were marked to adjacent Areas. Only one whale (Discovery mark number 11201) was recorded to move from Tonga (suggested to be one of the breeding grounds for Area V) where it was marked to the feeding grounds of Antarctic waters in Area I. There is an additional Discovery mark (number 11205) that has not been included in this analysis due to the mark being found in the cooker on a factory whaling ship, which was also recorded to have made a similar movement.
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E D
F B C
A
G
IV V
III VI II I
Figure 3.6: Marking and recovery locations for all Southern Hemisphere humpback whales from which marks were recovered under the IMS. Breeding Stocks A-G and Antarctic Areas I-VI are shown.
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Table 3.5: IWC Management Areas and Breeding Stocks for Discovery marking and recovery location for all marks recovered.
Note: percentage of mark recaptures are shown in italics. Percentages are calculated by row and not column.
Location of No. RECAPTURED marking MARKED Area Area Area Area Area Area BS A BS B BS C BS D BS E BS F BS G Total I II III IV V VI 3 Area I 61 0 0 0 0 0 0 ** 0 0 0 0 0 0 3 100% 2 Area II 21 0 ** 0 0 0 0 0 0 0 0 0 0 0 2 100% 5 2 Area III 112 0 0 0 0 0 0 0 0 0 0 0 7 71% 29% 9 29 1 Area IV 569 0 0 0 0 0 0 0 0 0 0 39 23% 74% 3% 4 7 11 Area V 319 0 0 0 0 0 0 0 0 0 0 22 18% 32% 50% 1 1 Area VI 16 0 0 0 0 0 0 0 0 0 0 0 2 50% 50% BS A 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 BS B 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 BS C 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 12 BS D 181 0 0 0 0 0 0 0 0 0 0 0 19 37% 63%
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Location of No. RECAPTURED marking MARKED Area Area Area Area Area Area BS A BS B BS C BS D BS E BS F BS G Total I II III IV V VI 1* 7 24 2 76 BS E 1,816 0 0 0 0 0 0 0 0 110 1% 6% 22% 2% 69% BS F 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 BS G 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Total 3,111 4 2 5 27 31 1 0 0 2 43 89 0 0 204
Notes: * Discovery mark recovered but found in the “cooker” and not included in analysis.
** Second Discovery mark recovered in a similar location but found in the “cooker” and not included in analysis.
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The average length of time between marking and recovery was 24.7 months (727 days) with a Standard Error of 1.9 months. The range in length of time between marking and recovery was from less than 24 hours to 6,388 days or approximately 17.5 years. Figure 3.7 shows the number of Discovery marks by duration between marking and recovery shown in months.
90
80
70
60
50
40
Number Number marks of 30
20
10
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Time between deployment and recovery (Years)
Figure 3.7: Duration in years between Discovery tag marking and mark recovery.
If movement from an Area is a function of whales gradually drifting over time, with no particular attachment to any feeding aggregations, then an increase in the recorded longitudinal movement of whales in relation to the time since marking would be expected. A regression of time since marking and longitudinal movement does not indicate a strong correlation between these factors (R2 = 0.015; Figure 3.8).
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80
70
60
50
40 Longitude 30
20
10
0 0 250 500 750 1000 1250 1500 1750 Days
Figure 3.8: Relationship between number of days before recapture of Discovery mark and longitudinal movement of humpback whales (R2 = 0.015).
3.6 DISCUSSION
This review of Discovery mark data has further supported the original findings of Mackintosh (1942), Chittleborough (1959a), Dawbin (1965a) and Brown (1978) in relation to there being a number of discrete stocks within the SHH. Within each major oceanic breeding stock, discontinuous patterns of seasonal distribution and observations of migratory movement by marked individuals suggest that humpback whales form relatively discrete subpopulations that are not separated by obvious geographic barriers (Kellogg 1929; Mackintosh 1965). Within each ocean there are potentially several ‘stocks’ with low levels of interchange.
3.6.1 Why is Discovery tagging important for management?
Historically the management of whale stocks has been based on information collected in the feeding areas as this was where the majority of whaling was undertaken. Following the introduction of the moratorium, there was little or no whaling on feeding grounds (with the notable exception of Japanese scientific whaling) and so there was little new information available from these areas. As a result, emphasis slowly switched to the investigation of breeding grounds, groups and/or stocks, and migratory corridors as these areas are much more accessible for research and monitoring. New techniques including the use of natural markings,
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satellite tagging and genetic analysis evolved in support of the non-lethal surveys being undertaken in these areas (Clapham 2000). As a result, the IWC recognised distinct breeding groups in 1998 (IWC), and used these groups as a key component of their ongoing Comprehensive Assessment of Southern Hemisphere Humpback Whales (CASH).
A key element of the IWC CASH was the estimation of pre-exploitation size from which it is then possible to estimate the level of depletion (or recovery) of a stock – a critical step in determining if a stock could support whaling and, if so, to what degree. While it is, of course, impossible to know the pre-exploitation size, it is possible to estimate it by modelling backwards from known catches and life history parameters (Gales et al. 2011). During this modelling it was determined that the pre-exploitation size for SHH was particularly sensitive to the proportional allocation of catch from Antarctic management areas. This was relatively straight forward when catches and abundance estimates were undertaken for common areas (that is, the IWC Management Areas) but becomes very complex when these estimates came from separate locations: as is the case for SHH where catches were made on Antarctic feeding Areas but population estimates were derived from tropical and temperate breeding areas or migratory corridors. The allocation of catches from feeding areas to populations on breeding areas becomes very complex and requires a detailed understanding of the mixing rates of different breeding groups on the feeding grounds.
Being unable to allocate catches from feeding grounds to breeding grounds means that it is not possible to estimate pre-exploitation size and therefore it is not possible to estimate the level of depletion or recovery. The allocation of catch related to EAH during the listing of Oceania humpback whales (Breeding Stocks E and F) as endangered by the IUCN (Childerhouse et al. 2008) provides an excellent example of this issue. It was not possible to develop separate estimates of pre-exploitation size for all the five sub-populations within Breeding Stocks E and F, and so they were all combined into a single assessment with the outcome that overall, there remained a relatively high level of depletion. This led to odd results whereby some stocks such as EAH (which is showing strong recovery) were given the same endangered status as Fiji (a stock barely recovered from whaling). This highlights the importance of understanding movements and inter-connectedness and the single best source of this information prior to the development of molecular techniques was Discovery marking.
Since the mixing of SHH on the high latitude feeding grounds is still poorly understood, one of the major challenges in assessing populations by breeding stocks is the allocation of catches
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in Antarctic waters (where the bulk of catches occurred) to breeding stocks. Given this uncertainty, a summary of migratory connections and discussions on the implications for stock structure on a stock-by-stock basis is essential.
3.6.2 Discovery tagging by breeding groups and feeding grounds
The following sections provide a breakdown of Discovery marks recovered by breeding stocks and feeding grounds. There is a particular emphasis on Breeding Stock E, which includes EAH as this is the primary focus for this thesis.
Breeding Stock A (Western South Atlantic) Six whales were marked on breeding grounds and 21 whales were marked within the putative feeding grounds of this breeding stock (feeding grounds to the south of the breeding grounds - Area II). There were no recoveries of marks from the breeding grounds and all marks deployed on the feeding ground were recovered from the same region. However there was an unconfirmed movement between a mark fired in Area I in Antarctic waters at 116° W was recovered off Brazil at 45° W (Breeding Stock A), however due to the mark being recovered from the cooker on a factory ship, the reliability of this recovery is poor.
Breeding Stock B (Southern West Africa) There were no marks recorded as being deployed or recovered within these breeding grounds. There were 112 marks deployed in Area III, which is a putative feeding ground of Breeding Stocks B and C (note: Area II has the potential to also be a putative feeding ground of Breeding Stock B). There were no migratory connections between any Antarctic feeding areas and Breeding Stock B.
Breeding Stock C (Southern East Africa) There were a total of seven marks recorded as being deployed within the breeding grounds of Breeding Stock C and 112 marks deployed in Area III, which is the putative feeding grounds of Breeding Stocks B and C. There were no recoveries of any of the marks deployed from the breeding grounds and seven recoveries from marks deployed in Area III. Two of these recoveries were whales which migrated from the feeding grounds within Area III to the Southern coast of Madagascar (Breeding Stock C). The other five recoveries were all within the Area III feeding grounds.
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Breeding Stock D (Western Australia) There were a total of 181 marks deployed within the breeding grounds of Breeding Stock D and 569 marks deployed in Area IV, which is the putative feeding grounds of Breeding Stock D. Of these, 59 marks were recovered of which 58 (98%) were recovered within the breeding grounds of Breeding Stock D or within the feeding grounds of Area IV. This demonstrates a very strong link between the breeding grounds on the west coast of Australia and feeding grounds within Area IV. Only one whale (2%), which was marked in Area IV, was recorded to move outside of this Area. This mark was recovered off the east coast of Australia in Breeding Stock E1. Apart from this single movement from Antarctic Area IV to the breeding grounds of Breeding Stock E1 no other marks deployed off Western Australia or in Antarctic Area IV have been recovered east of 130° E. However, illegal whaling effort in this region was particularly concentrated and marks may have been recovered but not reported by the Soviets (Clapham et al. 2009). Additionally no whales marked in Antarctic feeding Area V (130° – 170° E) have been recovered off Western Australia within breeding grounds for Breeding Stock D.
Breeding Stock E (East Australia, New Caledonia, Tonga) Breeding stock E is subdivided into three stocks within the South West Pacific (eastern Australia (E1), New Caledonia (E2) and Tonga (E3)). A total of 1,816 Discovery marks were deployed within the breeding grounds for these stocks with the bulk of the effort associated with land-based whaling stations at Tangalooma and Byron Bay on the east coast of Australia. Lesser Discovery marking effort was also associated with whaling stations at Norfolk Island (Australia), Cook Strait (NZ) and in Tonga. In addition, Discovery marking was undertaken independent of whaling activities at a range of locations in the South Pacific including Fiji, Vanuatu and New Caledonia.
In addition, a further 319 whales were marked within the putative feeding grounds for Breeding Stock E within Antarctic Area V. Unlike Breeding Stock D, which has a very defined connection with Area IV, Breeding Stock E would appear to have a very broad longitudinal distribution across several Antarctic feeding areas.
While there are a number of mark recoveries that demonstrate links between the breeding grounds of Breeding Stock E and Antarctic Area V, there are also a number of movements that demonstrate that this breeding stock feeds across a very wide longitudinal area (up to 178°) within the Antarctic feeding grounds. Links include movements between Antarctic Area V and the east coast of Australia, Norfolk Island, NZ and Tonga.
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There are five connections between the breeding grounds on the east coast of Australia (Breeding Stock E1) and the feeding grounds within Area IV and also one between Fiji and the Area IV feeding ground. It is not known with which breeding stock Fiji aligns and it may be that it is more closely aligned E2 or E3 rather than E1. Alternatively, it could represent a separate and new breeding stock within the South West Pacific. The record from Fiji moving to the western side of Antarctic Area IV is one of the longest movements recorded for a humpback whale (92° longitudinal with a straight line distance between marking and recapture of approximately 8,300 km). There are also four additional connections between feeding grounds of Area V and Area IV.
A single animal, which was marked in Tonga (Breeding Stock E3), was recovered from the Area I feeding area. This mark recovery is complemented by a second mark from Tonga, which was also recovered in a similar location within Area I. The accuracy of this recovery is unknown, however, as it was recovered from a cooker on a whaling vessel. The connections between E1 and E2 with the feeding grounds in Antarctic Area V are further supported by photo-identification matches (Franklin et al. 2008; Constantine et al. 2014), genotype matches (Steel et al. 2008; Constantine et al. 2014) and satellite tracking data (Gales et al. 2010).
There is good evidence that whales from Breeding Stock E fan out to feed in a broad area of Antarctica including waters south of Western Australia, Eastern Australia, NZ and potentially Tonga and French Polynesia (Area I). However, it is difficult to draw sound conclusions on migratory interchange with some feeding areas due to small sample sizes. The records of migrations from Tonga are supported by recent genotype matching, which also recorded matches between Tonga and the western component of Antarctic Area I (Steel et al. 2008). In addition, Robbins et al. (2011) also reports return movements of humpback whales from the Antarctic Peninsula (Area I) and American Samoa (Breeding Stock E). There are now several connections (n=6 including one Discovery mark, three photo-identification matches, two genotype matches, plus one unconfirmed recovery of a Discovery mark from a cooker) between the eastern region of Breeding Stock E (specifically Breeding Stock E3) and Area I. Only one link is known between Tonga and Area V. In the absence of further evidence linking Tonga to feeding Areas V or VI, Area I (including the Antarctic Peninsula) would appear to be an important feeding area for whales breeding in the eastern side of Breeding Stock E (Tonga and Samoa).
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In addition to these connections between the feeding grounds and the breeding grounds there are also 18 movements based on Discovery mark data within Breeding Stock E and between Breeding Stock E and D. These include:
Within Breeding Stock E:
Eight movements of animals recorded moving from NZ (migratory corridor) to eastern Australia (Breeding Stock E1); One within season movement of a female marked in Cook Strait in June 1960 and killed off Moreton Island, eastern Australia 20 days later; Three movements from eastern Australia (Breeding Stock E1) to NZ; Two movements between Fiji and NZ; One movement each from Norfolk Island to NZ; and One movement from Fiji (Breeding Stock E2/E3) to Eastern Australia (Breeding Stock E1).
From Breeding Stock E to Breeding Stock D:
Two movements from eastern Australia (Breeding Stock E1) to Western Australia (Breeding Stock D).
These migratory connections between breeding and feeding grounds and within breeding stocks are complemented by recent extensive:
Photo-identification matching and genotype matching (Kaufman et al. 2011; Garrigue et al. 2004, 2011a; Franklin et al. 2008; Steel et al. 2008, 2011; Anderson 2013; Constantine et al. 2014; Schmitt et al. 2014); Satellite tag data (Gales et al. 2009); and Investigation into the evolution of humpback whale song within the South West Pacific (Garland et al. 2011).
While these migratory connections demonstrated by Discovery mark data have now been supported by other research data, it is worth noting that the Discovery mark data predates these other technologies by up to half a century and at that time was the only source of information on movements and stock structure. While recent research has shown some interesting new findings, it is reassuring that results from these recent studies are broadly compatible with the stock structure hypotheses that were developed from Discovery mark data.
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Discovery mark and satellite tracking data indicate that the bulk (>70%) of whales from E1 feed within Antarctic waters between 140° E and 175° W. However, a proportion of animals from Breeding Stock E1 (potentially up to 25% based on Discovery mark and satellite tag data) overlap with animals from Breeding Stock D in Antarctic waters between 100° E and 140° E. While there are a number of biases associated with the Discovery mark and satellite tracking data, such as small sample sizes and the inability to confirm the catch per unit effort for whales within the feeding grounds, these data are important in relation to the allocation of historical catch data.
This indicates that in order for the allocation of historical catch data to be consistent with the Discovery mark data and other more recent information (Jackson et al. 2008), the historical IWC stock boundary for the core area (or nucleus zone – that is, a zone in which all whales that were caught can be allocated to a single breeding stock) for Breeding Stock D should be moved west to at least 110° E. The area between 110° E and 130° E should be considered an overlap zone (or fringe/margin zone – that is, a zone within which whales caught could be allocated to more than one breeding stock) where historical catch data should be allocated 50:50 between Breeding Stock D and E1 (Jackson et al. 2008).
Breeding Stock F (French Polynesia) There were a total of three marks recorded as being deployed within the breeding grounds of Breeding Stock F and 16 marks deployed in Area VI, which are the putative feeding grounds of Breeding Stock F. There were two recoveries of whales marked in Antarctic Area VI. One whale marked on the western edge of Area VI was recovered on the east coast of Australia and the other was recovered within the Antarctic feeding Area VI. Though it may be a function of small sample size, at present there appears to be no migratory connections for humpback whales feeding in Area VI and breeding in Breeding Stock F.
Breeding Stock G (Columbia) There were no Discovery marks recorded as being deployed within the breeding grounds of Breeding Stock G and 61 marks deployed in Area I, which are the putative feeding grounds of Breeding Stock G. Of the 61 marks deployed within Area I, four were recovered within the same Antarctic feeding Area. One mark was recovered off Brazil (Breeding Stock A) and was found in the cooker of a whaling vessel. In addition, two marks deployed in Tonga were recovered in Area I. One of these was recovered from a cooker. The recoveries of two Discovery marks from Tonga in Area I is supported by recent genetic data (Steel et al. 2008)
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and return migrations between Samoa and the Antarctic Peninsula of two whales documented by photo-identification matches (Robbins et al. 2011). This raises an interesting question in relation to the allocation of historical catch data for this region.
3.6.3 Potential limitations of the data
Potential limitations associated with the Discovery mark data set must be taken into consideration when drawing conclusions from these data. These limitations can restrict the utility of the data but are very difficult to address and/or quantify with any certainty. Specifically, the following factors represent potential limitations of Discovery mark data:
Discovery marking deployment effort was not equal across all regions; Whaling effort (that is, recovery effort) was not equal across all regions; Some animals may have been fatally injured during marking operations and therefore their marks were unavailable for recovery; The inability to recover data without killing a whale means that only data of the marking location and recovery were available; Limited data are available on catch per unit effort for whaling activities in the Southern Ocean, and some data are of dubious reliability due to the Soviet whaling fleet falsifying records in order to conceal extensive illegal whaling activities; Evidence to suggest that a substantial number of marks that were recovered, were unreported or had falsified records with respect to species, location and date, in order to conceal illegal whaling activities; and The small sample size in some regions makes it very difficult to draw accurate conclusions. These limitations must be borne in mind when interpreting the data and drawing conclusions. However, in some ways this research has an advantage in that it is possible to clearly identify the limitations even if it is not possible to quantify them reliably. Having an understanding of actual limitations allows an assessment to be made about the impact of these on resulting conclusions, which can then be framed in light of the limitations. As long as these limitations are known and accounted for in a sensible way, Discovery mark data can be a powerful tool for investigating humpback whale ecology. Furthermore, notwithstanding these limitations, these data are the single best source of movement and migratory interchange information prior to the development non-lethal research techniques.
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Any thorough examination of mark-recapture data must consider the level of effort of both marking and recovery (Donovan, 1991). Discovery marking effort (as shown in Table 3.2 and Figure 3.5) has not been equal across all Areas and Breeding Grounds. The majority of marking effort (91% of confirmed hits) occurred in Areas IV and V. This marking effort was not distributed evenly: 65% of conformed hits were undertaken on the breeding grounds/migratory corridor and 35% on the feeding grounds. In the breeding grounds and the migratory corridor, Discovery marking effort was concentrated at a limited number of locations associated with land-based whaling stations (such as Tangalooma, Byron Bay, Norfolk Is, Carnarvon (all in Australia), Cook Strait in NZ and in Tonga). In addition, Discovery marking was undertaken independently of whaling activities at a range of locations in the South Pacific including Fiji, Vanuatu, New Caledonia and several other locations.
In Antarctic waters, Discovery marking effort was undertaken during whaling operations and dedicated Discovery marking expeditions (Mackintosh 1942; Chittleborough 1959a; Dawbin 1956b). In the feeding grounds the marking effort was also biased towards Areas IV and V, with 30% and 54% of the Discovery marking occurring in these Areas respectively. The lack of Discovery marking effort in some areas is generally consistent with a lower level of whaling operations there. This may be attributed to extensive whaling effort depleting whale stocks in these regions prior to the development of the Discovery mark (Brown 1978). Whaling in Area II supports this theory. Extensive whaling effort was reported in Area II between 1909 and 1915 with over 50,000 humpback whales reportedly taken principally in the waters around South Georgia (Mackintosh 1942), however, very few marks were deployed there.
The whaling data also show a strong bias towards catch effort in Areas IV and V, with 29% and 41% of the total catch of SHH between 1947 and 1973 recorded in these Areas respectively (Clapham et al. 2009) (see Figure 3.9 and Figure 3.10). Approximately 36,000 humpback whales were taken from 120° E-170° W and approximately 8,150 whales were killed between 170°-110° W. Between 1959 and 1964, illegal Soviet whaling in the Antarctic Areas associated with eastern Australia and Oceania killed over 29,000 whales (Clapham et al. 2009).
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45000
40000
35000
LED 30000
25000
Series1
20000
15000 NUMBER OF WHALES KIL OF WHALES NUMBER
NUMBER OF WHALES KILLED NUMBER OF WHALES
10000
5000
0 AREA I AREA II AREA III AREA IV AREA V AREA VI NOT ASSIGNED AREA
Figure 3.9: Number of humpback whales killed by Area between 1947 and 1973. (Source Clapham et al. 2005.) Note: Illegal Soviet catches were primarily taken in areas IV and V, which makes those catches appear disproportionately large.
30000
25000
20000
15000
10000
Number of whales Number whales of killed 5000
0 BS D Area IV BS E Area V Regions
Figure 3.10: Number of whales killed by Breeding Stock and feeding grounds for Areas IV and V between 1947 and 1973. Note: there were an additional 7,177 Soviet catches that were not assignable to any Areas. (Source Clapham et al. 2009). Note catches in graph are divided at 50° S with catches to the north shown in relevant breeding stock and catches to the south allocated to relevant feeding area.
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Figure 3.10 indicates the relationship between the number of whales caught within Areas IV and V and their putative breeding grounds (Breeding Stocks D and E). It is noteworthy that whaling on the west coast of Australia accounted for 45% and Antarctic whaling 55% of whales caught associated with Breeding Stock D. This differs for whales associated with Breeding Stock E, with 27% of these whales caught on eastern Australia, Norfolk Island and NZ, whereas whaling in the southern Ocean (mainly illegal Soviet whaling) accounted for 73% of whales taken from this breeding stock.
There is also some debate about the accuracy of the outcome of marks deployed. Chittleborough (1959a) estimated that up to one third of humpback whales with a deployment recorded as a possible hit could result in successfully marked whales. The results in Table 3.4 indicate that this would be an overestimate for humpback whales in the SH. Ohsumi (1995; in Buckland and Duff 1989) undertook analysis of mark recoveries for minke whales and estimated that the true number of hits is 1.3 times the recorded number of definite hits. Joyce (1984, 1985 in Buckland and Duff 1989) considers the results of video experiments of marking of minke whales comparing marks with and without streamer. He estimates that for streamer marks there is a 10% underestimation of the number of hits if only definite hits are used; and for non-streamer marks the underestimation is between 20-21%. However, Best (pers. comm. 2005) has suggested that the number of confirmed hits (false positive bias) may well be an overestimate of the successful marking. Best’s assessment is consistent with that of Chittleborough (1959a).
Table 3.1 shows that very few whales with Discovery marks were ever recovered even though a high percentage of all SHH were caught and killed. This provides good evidence that a very large proportion of the whales with records as hit, were actually unlikely to have actually been successfully marked or they may have been marked and the Discovery marks were subsequently rejected and so not found when caught and processed.
Chittleborough (1959b) suggests that a protruding hit will result in the Discovery mark falling out in a very short time due to it not being lodged fully below the skin into the muscle layer. The data for Discovery mark recoveries from humpback whales supports this hypothesis of mark loss, with only the recovery of two marks that were recorded as protruding hits. Both marks were recovered from humpback whales within a very short period following marking (within one and two days). Based on these results, and assuming a 20-21% underestimate in
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successful marking, it is reasonable to determine that there would have been up to 21 (12%) additional marks expected to be recovered.
A major limitation in the use of Discovery marking data for the examination of stock structure and the assessment of movement patterns is that there is a significant bias in marking effort and that recoveries could only be made in areas where whaling was undertaken and so no recoveries or data are available for the overwhelming proportion of the SH. A rare exception to this is that a few marks have been recovered from stranding events (Dawbin, IMS Discovery marking logbook). This is further confounded in that whaling activities, particularly in the breeding grounds and migratory corridors, were targeted to very specific locations, further limiting the geographic spread of both deployment and recovery effort.
Another shortcoming is the low reported recovery rate of marks (6.5% of confirmed hits), especially when considering the large marking effort and the rapid and extreme decline reported in the SHH associated with whaling activities (Clapham et al. 2005). Table 3.2 and Table 3.3 indicate that the bulk of marks were deployed (65%) and recovered (68%) north of 50° S in the breeding grounds and migratory corridors. The high recovery rate (68%) within the breeding grounds and migratory corridor is inconsistent with the expected Discovery mark returns from the Southern Ocean, where the majority of the whaling effort was concentrated in Area IV (55% of whales taken from this population) and V (73% of whales taken from this population).
Table 3.6 shows that the number of marks returned when weighted for the number of whales caught, is substantially lower in Area V than the other regions. In addition the number of marks returned when weighted for the number of whales caught for the combined regions of Breeding Stock E and Area V (the putative feeding Area for this population) is substantially less than that recorded for the combined figures for Breeding Stock D and Area IV. These are indicative figures only due to limitations with the data. Particularly limiting factors include the allocation of historical catch data and assumptions such as all whales that were marked in a particular Breeding Stock were available for recapture in the corresponding putative feeding area. This thesis has already shown this to be untrue. Due to these limitations and uncertainties it was determined that these data do not warrant further statistical analysis.
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Table 3.6: Number of humpback whales caught, humpback whales marked, marks returned, proportion of marks returned and proportion of marks returned weighted by whaling effort.
Region No. Whales Marks Proportion of Proportion of whales marked returned marked marks returned caught returned weighted by whaling effort BS D 12,312 181 19 0.105 0.85 Area IV 14,889 569 39 0.069 0.46 BS E 10,422 1,816 110 0.061 0.58 Area V 27,724 319 22 0.069 0.25 Total 65,347 2,885 190 0.066 0.10 BS D and Area IV combined 27,201 750 58 0.077 0.28 BS E and Area V combined 38,146 2,135 132 0.062 0.16
The rate of recovery of Discovery marks is just over half the figure reported for Discovery mark returns by Ivashin (1973) under the SMS for humpback whales in the SH. Under the SMS, a total of 547 humpback whales were reportedly marked in the SH. Of these, a total of 62 (11.3%) were reported as being recovered (Ivashin 1973). This difference in recovery rates between the two Discovery marking schemes, especially with such a small sample size deployed by the SMS, would indicate that it is highly likely that the Soviet whaling fleet did not report a significant number of Discovery marks associated with the IMS, presumably to hide their illegal whaling activities.
Assuming a similar percentage of returns under IMS as the SMS (note: data from the SMS Programme is not currently available upon which to undertake a review to determine any biases in scoring of relative success of hits between programmes), it would be expected that a total of 147 Discovery marks were recovered but unreported. This figure could well be an underestimate as the marking effort under the IMS was significantly higher (5.6 times the marking effort of the SMS). In addition, the returns would have been expected to be even higher given that the bulk of the marking effort (91% of confirmed hits) and whaling catch effort with 29% and 41% of the total catch for the SHH catch between 1947 and 1973 occurred in Areas IV and V. It is highly probable, therefore, that a proportion of marks that were recovered, were unreported or had records falsified with respect to species, location and date, in order to conceal
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illegal whaling activities. The resulting uncertainty regarding the reliability of SMS records was the rationale for not using them as part of the analysis in this thesis.
3.6.4 Migratory Interchange – what drives it?
This study has identified a low level of migratory interchange, particularly within Breeding Stock E and between Breeding Stocks E and D, and Breeding Stock E and feeding areas IV and I. It is impossible to determine why whales moved where they did but some general conclusions can be made based on what we now know about humpback whale movement and migration patterns in the SH (Clapham 2000). Although tempting, drawing conclusions from the NH may not hold true for the SH as humpback whale movements and migration patterns in the SH are not restricted by landmasses as they are in the NH.
Most movements are likely to be associated with animals following annual migrations between tropical breeding grounds and Antarctic feeding grounds (generally in a north/south orientation). While there are no impediments for dispersal on the feeding grounds in the Southern Ocean there are multiple processes influencing movement patterns. Proximate causes vary but include local population conditions such as crowding and food availability. Environmental stochasticity (for example weather, species interactions) also contributes to substandard conditions in the local environment and may affect changes in both dispersal and general behavior (such as aspects of phenology including migration and breeding). Individuals that emigrate as a result of environmental conditions may experience more favorable conditions in the new location. Movements within feeding grounds are likely to be associated with whales searching for and finding krill concentrations that will vary from year to year as a result of environmental factors as suggested by Chittleborough (1959a).
Rekdahl (2012) found that song evolution events occurring in the EAH population (indicating influence from the west Australian population) were episodic. These song change events were tied to El Niño-Southern Oscillation events. It is therefore highly possible that, environmental influences were driving the movements between the east and west Australian populations. However Noad et al. (2000) and Garland (2011) have shown that the song transition is typically from west to east whereas the bulk of the movements (>90%) between the east and west coasts of Australia, has been in a westerly direction (see Noad 2000 and Garland 2011 for details on song transition and methodology used to determine direction of movement). Garland (2011) suggested that whales may move west, learn the new song type and then move back to the east to their natal population, and consequently spread the song type. As the song on the east coast
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of Australia is effectively the “old” song that originated from the west coast, it would not likely be a breeding advantage for males from the east coast to take the “old” song back to the west coast since females will already be familiar with it and it would not be novel and attractive. The Discovery mark data indicated only one incident of a whale moving from the putative feeding grounds of the west Australian population to the east coast of Australia. Photo- identification, genetic and satellite data also confirm very limited evidence of movements of whales from west to east.
Another possibility is as a process of dispersal of animals (particularly males) away from genetically related females, consistent with that recorded in a range of other species (for example, Croteau 2010). Schmitt et al. (2014) found that although the east and west Australian populations are genetically distinct, there was only weak differentiation in mitochondrial DNA and microsatellite loci. This suggests some movement of both males and females between populations. Therefore the idea that dispersal of animals (particularly males) away from genetically related female humpback whales is unlikely, due to the low level of movement shown in the results (see Table 3.5) and evidence of males and females dispersing.
An alternative theory by Zerbini et al. (2010) suggests that animals emigrate from regions with very small populations (such as found in Oceania) to other regions where there are high densities of whales, resulting in increased chances of finding a mate and reproducing (for example, eastern Australia). This may help explain the much higher recovery rate of the EAH population and the suggestion by Valsecchi et al. (2010) of genetic substructure detected in the EAH migrating population. However, while Discovery mark and photo-identification data provide some evidence to support this theory (that is, a number of connections between NZ, New Caledonia and Australia), there is limited evidence of movements from other regions in Oceania.
3.6.5 Overall conclusions
Discovery marks were the only way to learn about movements and migratory interchange prior to satellite tags, genetic analysis, photo-identification and analysis of humpback whale song; 3,111 marks deployed, 204 (6.5%) recovered: mostly on the migratory corridor for Breeding Stock D and E, and feeding areas IV and V; Discovery marks have limitations: Recovery of a mark requires the killing of a whale;
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Uneven and non-random effort in time and space for deployments and recoveries restricts the utility of the data; and Illegal Soviet whaling probably caught a large percentage of the humpback whales available within the Southern Ocean in the late 1950s and 1960s, but catches were not reported or records were falsified, and marks returns were not necessarily reported. Major conclusions are: Breeding Stocks D and E, and Areas IV and V are the only regions with useful amounts of available data. Sampling rates in the other regions are too low to be meaningful; Discovery marks have confirmed links between Breeding Stocks C, D and E and their putative feeding grounds in the Antarctic to the south of the breeding grounds; Discovery marks provided the first empirical evidence of large scale movements of humpback whales in the Southern Hemisphere and their use considerably increased and strengthened our understanding of the movements of whales and the complexities that these added to conventional stock structure hypothesis; Discovery marks provided evidence of longitudinal structuring of SHH, which is important for management; Discovery mark data generally confirmed existing IWC Management Areas; Discovery mark data have demonstrated movements between management Areas but probably at low levels; While most populations follow traditional north south migrations, Breeding Stock E did not follow this conventional movement pattern. Instead they had a much wider longitudinal distribution on feeding grounds; The dispersal of whales from Breeding Stock E has a wide distribution beyond that originally considered to be the putative feeding area in Area V. That is, extending from Antarctic Area IV to Area I covering a range of approximately 175° of longitude (nearly half the globe). Dispersal of whales from Breeding Stock C is consistent with this finding, however, with a sample size of n=2 it is difficult to draw definitive conclusions from these data;
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Discovery mark data have documented a much wider distribution of whales from Breeding Stock E than was previously known; These data have been highly influential in the allocation of catch on Antarctic feeding grounds to tropical breeding grounds, critical for undertaking a Comprehensive Assessment of Southern Hemisphere Humpback Whales (CASH) at the IWC; Subsequent new analysis using satellite tags, genetic analysis, and photo- identification have generally confirmed the conclusions from Discovery mark data (despite its limitations); and Additional data from the SMS are potentially available, but due to concern regarding reliability have not been included in this analysis.
The data presented in this thesis as well as those from other researchers indicate that the IWC stock boundaries in the Antarctic used for the allocation of historical catch data may require revision. These data form part of the CASH stocks.
The stock boundaries for the allocation of catch data have changed many times in recent years as new data pertaining to migratory connections have become available. The IWC agreed stock boundaries are shown in Figure 3.11. The Discovery mark information in this chapter was presented at the 2006 IWC CASH meeting in Hobart and has assisted in updating these boundaries.
Figure 3.11: New hypothetical stock structure for Southern Hemisphere humpback whales. Note: this is for illustrative and discussion purposes only. The areas and subareas identified reflect approximate boundaries. A dotted line represents hypothetical connection; thin lines represent a small number of documented connections
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between areas from re-sights using Discovery marks, photo-identification, genetics, or satellite tracked whales; and thick lines represent a large number of documented connections between Areas from re-sights using Discovery marks, photo-identification, genetics, or satellite tracked whales. (Source Gales et al. 2011). Longitudinal boundaries encompass Antarctic feeding areas considered associated with those stocks.
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CHAPTER 4 POPULATION GROWTH OF AUSTRALIAN EAST COAST HUMPBACK WHALES, OBSERVED FROM CAPE BYRON, 1998 TO 20042
4.1 ABSTRACT
Humpback whales (Megaptera novaeangliae) that migrate past the east coast of Australia comprise part of Group V (E1 breeding stock). From 1995 to 2004 an annual 16-day survey was conducted from Cape Byron (28°37’S, 153°38’E), the most easterly point on the Australian mainland, monitoring the peak of the humpback whale northern migration. The annual rate of increase between 1998 and 2004 of humpback whales observed off Cape Byron is 11.0% (95% CI 2.3–20.5%). This rate of increase is consistent with that recorded from other studies of the humpback whale population off the east coast of Australia. The large confidence intervals associated with this estimate are due to considerable inter-annual variation in counts. The most likely explanation for this being the short survey period, which may not have always coincided with the peak of migration, and in some years a larger proportion of whales passed Cape Byron at a greater distance out to sea, making detection more difficult.
4.2 INTRODUCTION
Humpback whales (Megaptera novaeangliae) migrate north from Antarctica, along the east and west coasts of Australia during the Austral winter, to breed and give birth in the warm waters of northern Australia. The humpback whales that pass the east coast of Australia are thought to comprise part of the group that feeds in Antarctic Area V (130° E to 170° W). This
2 This paper is published as: Paton D, Kniest E (2011). Population growth of Australian East Coast humpback whales, observed from Cape Byron, 1998 to 2004. Journal of Cetacean Research and Management (Special Issue) 3, 261–268. Refer to Appendix I for a direct reprint of this paper. Copyright permission from the journal has been obtained. A statement of contributions to this paper is included in section 1.5.3.
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group is therefore identified as ‘Group V whales’. Recent studies suggest that there is sub- stock structure on the tropical breeding grounds and that these sub-stocks intermingle to at least a small degree (Garrigue et al. 2000). Group V humpback whales on their tropical breeding grounds have been divided into three sub-stocks known as: Breeding Stock E1, those wintering off the Australian east coast; E2, those wintering around New Caledonia; and E3, those wintering around Tonga (Bannister 2005; Olavarría et al. 2006). Breeding Stock E1, the Australian east coast population, is the largest.
Historically, the Group V population was hunted from both land- and vessel-based operations throughout its migratory range, including the East Australian coastline and the Antarctic. Land-based whaling was conducted from several locations on the east coast of Australia, commencing in 1952. These locations included Twofold Bay, Jervis Bay, Byron Bay and Tangalooma on Moreton Island. Other locations where whaling activities occurred in the South Pacific include Norfolk Island, Cook Strait in New Zealand and Tonga. Small numbers of whales were also taken in Fiji and Vanuatu. Considerable illegal hunting of humpback whales was undertaken in Antarctic waters from 1959 to 1961 by the Soviet Union (Paterson et al. 2001; Clapham et al. 2005).
Prior to the 1950s there was little exploitation of the E1 sub-stock. At this time the population size of the entire Group V population was estimated to be between 10,000 and 26,000 whales (Bannister and Hedley 2001; Chittleborough 1965). These figures are potentially an underestimate of the pre-exploitation population for Group V as the total number of 20th century humpback whale catches in Area V and in breeding area (E) was 102,398 whales (Clapham et al. 2005; Clapham and Zerbini 2006). Given the large number of whales killed and recent population modelling, it is now thought that the pre-exploitation population of the Group V whales was considerably larger than previously thought, potentially in the range of 30,000 to 40,000 humpback whales (Jackson et al. 2006).
The industrial shore-based whaling and large scale illegal pelagic whaling in the Southern Ocean resulted in a population collapse by 1962 (Chittleborough 1965). Estimates for the remaining population vary in size from 104 for all of Group V (Bannister and Hedley 2001) to 500 for the east Australian and New Zealand populations (Chapman 1974; Chittleborough 1965). These estimates are less than 5% of the pre-exploitation size. In the 45 years since 1963, the east Australian population of humpback whales is one of a number of populations that has shown strong recovery (Brown et al. 2003; Paterson et al. 2001). The apparent lack
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of recovery of whales migrating past New Zealand (Childerhouse and Gibbs 2006; Gibbs and Childerhouse 2000), and low numbers recorded in some regions of the South Pacific (Garrigue et al. 2002; Gibbs et al. 2003), indicate that the strong increases seen in East Australia have not been seen across other parts of the South Pacific.
Shore-based observation stations have been utilised to monitor trends in a number of populations of cetaceans (Bryden et al. 1996; Buckland and Breiwick 2002; Paterson et al. 2004). Long term studies have been conducted on humpback whales in KwaZulu, Natal (Findlay and Best 1996b) and North Stradbroke Island, Australia (Brown 1997; Bryden et al. 1996; Paterson et al. 2004; Noad et al. 2011a,b). Humpback whales migrate along the continental inshore waters along the east coast of Australia. Bryden (1985) demonstrated that the migratory corridor between Cape Byron and Cape Moreton, was particularly narrow, with 96% of humpback whales passing within 10 km of headlands within this region. The width of the humpback whale migration corridor was reassessed in 1991 (Brown 1997) and 2007 (Noad and Dunlop 2007) and found to be consistent with the results of Bryden (1985).
The demonstrated effectiveness of using shore-based observations to monitor cetacean population trends combined with the fact that humpback whales are known to migrate close to the coast off northern New South Wales, make Cape Byron an ideal location for a long term assessment of the recovery of the E1 Breeding Stock. This chapter reports on land- based counts collected between 1998 and 2004 and the observed increase in humpback whales observed off Cape Byron during this period.
The CASH process undertaken by the IWC involves an in-depth evaluation of the status of whale stocks. It includes the examination of issues such as current stock size, recent population trends, carrying capacity and productivity. This chapter provides valuable information on the recent population trend for EAH during their northward migration between 1998 and 2004. It is based on a paper presented to the IWC intercessional meeting in Hobart to undertake a CASH (Paton and Kniest (2006). Cape Byron humpback whale surveys, Eastern Australia, 1998 to 2004. Analysis of data collected during humpback whale sighting surveys at Cape Byron, Eastern Australia, 1998 to 2004. Unpublished IWC paper SC/A06/HW35). A manuscript with minor revisions from that presented in Hobart was published as Paton and Kniest (2011). Population growth of Australian East Coast humpback whales, observed from Cape Byron, 1998 to 2004. Journal of Cetacean Research
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and Management Special Issue 3 Humpback Whales: Status in the Southern Hemisphere: 261-268.
4.3 MATERIALS AND METHODS
Cape Byron is located at the most easterly point on the Australian mainland (28°38’S, 153°38’E). Early surveys were conducted from a location (28°38’19”S, 153°38’10”E) ca. 200 m from the most easterly point on Cape Byron. This location has an altitude of 83 m and unobstructed visibility from the south-southeast to the north-northeast (bearings of 190º to 346º). The Cape Byron Whale Research Project (CBWRP) operated at this location from 1995 until 1998. For the 1999 survey the CBWRP relocated to the upper balcony of the Cape Byron Lighthouse. This location (28°38’19”S, 153°38’11”E) is 173 m from the original land-based survey location and is 33 m higher (total height is 116 m above sea level). The new survey location had a slightly better outlook (south-southeast to the north-northwest) and access to a reliable power supply for operating a computer. It also provided shelter during inclement weather and improved accuracy for distance determination because of the increased altitude. In order to assess relative abundance of humpback whales migrating north past Cape Byron, detailed records were maintained in relation to effort (annual survey period – number of days, number of hours surveyed per day and number of observers on any given day). This information was used to evaluate and standardise to a common level data from the two observation locations in order to allow a direct comparison of data between years.
The timing for the CBWRP was based upon historical whaling data collected at the Byron Bay station, which operated between 1954 and 1962 (Chittleborough 1965). During this period 1,146 whales (primarily humpback whales) were taken near Byron Bay (Chittleborough 1965). The survey period was chosen to coincide with the peak of the catches at the whaling station during the northern migration as it is assumed that this peak catch related to the peak in numbers of the northern migration. Observations were carried out from the land station during a 16-day period annually (last week of June and first week of July). Observations were carried out between the hours of 07:00 and 16:30 daily, weather permitting. Observations were suspended when rain made it impossible to undertake surveys; when wind strength reached a point making it impracticable to operate (25–30 knots) or lightning activity made it unsafe to be in the lighthouse. Two shifts operated each day with a 15-minute overlap, the first from 07:00 to 12:00 and the second from 11:45 to 16:30.
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A software package named ‘Cyclopes’ was developed by staff and students from the University of Newcastle, Australia specifically for the CBWRP in order to improve and allow more reliable tracking of marine mammals and vessels. This real time tracking system uses an electronic theodolite interfaced to a laptop computer. The theodolite is used to acquire the location of the pod by measuring the horizontal and vertical angles to the pod, which are sent directly to the computer. Cyclopes then calculates the position of the pod correcting for tides, earth curvature and refraction. The program determines which pod was observed and plots its position on a map shown on the computer screen. Cyclopes also has the capability to record information regarding the pod’s make up, activity, speed, course, distance, direction and time of observation (Kniest and Paton 2001a,b). Pod size was estimated from shore and the best estimate was used. While this could be a potential source of bias, a research vessel would approach random pods to confirm pod composition.
The project operated with a mean of six observers (range 2–8). Due to operational requirements, during lighthouse tours (about half an hour a couple of times a week), the survey team was reduced to two experienced observers for this short period. Survey effort was consistent over the period of the study (1998–2004). Normal survey operations included at least two observers scanning the ocean to the south and east of Cape Byron, and at least one scanning to the north of Cape Byron. For over 90% of the observation period, an experienced observer was present to confirm sightings of pods, species and composition. An observer was deemed to be experienced if they had already been involved with the project for two years, or if they had several seasons of prior field experience working with humpback whales. A research vessel worked in conjunction with the land station to undertake fluke photo- identification, confirmation of pod size, collection of behavioural data and to collect genetic samples.
Observers used both the naked eye and binoculars (7×50 Tasco compass binoculars and 10×50 Nikon binoculars) to detect whales. Once pods were sighted, a theodolite operator (who was in addition to the dedicated observers) using a Leica TC1105 (or similar) theodolite would take fixes on the location of the pod and track movement of the pod while within the field of view of the land station. When additional personnel were available a person was dedicated to operating Cyclopes and assisting the research vessel to locate pods. At all times at least one observer was scanning for new pods.
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Records of effort and weather were kept during all observation periods. Weather information including wind speed and direction, cloud cover, sea state (Beaufort), swell, visibility (estimated in km) and any other factors such as smoke haze, were recorded using Cyclopes’ weather recording function. In addition Cape Byron headland has a meteorological station with detailed weather information available for the site from the Australian Bureau of Meteorology.
When pods were first observed and an experienced observer confirmed the species, the observers would estimate pod composition and continually track each pod as it approached Cape Byron from the south. The pod composition would be adjusted (and confirmed by an experienced observer) when necessary. Careful notes were taken when pods split or joined, or there was a sudden change in behaviour. Pod composition was confirmed by the research vessel when the vessel intercepted the pod. The research vessel, under normal operating protocols, operated north of Cape Byron so as not to potentially disturb the movements of whales prior to passing Cape Byron.
Observers would monitor a pod’s activity and direct the theodolite operator to the surfacing of pods. Where possible one event from each surfacing cycle would be fixed using Cyclopes to monitor the movement pattern of the pod. Once a number of sightings of the pod were recorded, the program was able to predict the direction and speed of travel and any changes in course or speed. These data were plotted in real time on the computer screen showing the trackline of pods passing the land station. The program was extremely useful in eliminating duplicate counts of the same pod especially when pods were located close together or when a pod was lost for a period of time.
4.4 ANALYSIS
To determine the number of whales (and pods) migrating past Cape Byron during the survey period, all sighting data were converted to a standard 10-hour day, consistent with the methodology used in other migratory humpback whale surveys (Brown 1997; Bryden et al. 1996; Paterson et al. 2004). The standard survey period was 9.5 hours, therefore sighting rate was scaled pro-rata to a 10-hour survey period. Due to the expansive field of view from the land station (over 180°), only pods that had crossed a line due east of Cape Byron during the survey period were included in the analysis. The time each pod passed the line extending east of Cape Byron was calculated by projecting from the pod’s closest observed position along a line representing its mean course and speed. These pods were included in the
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analysis if they were determined to have passed east of Cape Byron during the survey period. Only humpback whales observed travelling in a northerly direction were included in the analysis.
To avoid double counts or missing whales when pods split into separate groups or when other whales would join a previously tracked pod, the number of whales was only counted in the initial pod. After an affiliation or disaffiliation of a pod occurred, the new pods formed would be assigned new names. During analysis these pods would have the number of whales in the pod set to zero (although the pod composition is still noted). For example if pod ‘D’ (size = 1) joined pod ‘H’ (size = 2), the new pod formed would be called ‘H/D’ with composition noted as 3 but the pod size is assumed to be zero for the sake of determining whale counts; and the new pod is not included in the count as an extra pod.
Determining which days should be excluded from the analysis due to adverse weather can be subjective. For the purposes of this analysis, the following protocol was used for the exclusion of days: (1) days with a mean sea state greater than Beaufort 3 and/or mean visibility less than 15 km for extended periods; and (2) days on which fewer than five hours of survey were conducted.
Each day’s count was converted to a standard 10-hour count for that day, given by:
퐶𝑖 = 10⁄ℎ𝑖 × 푁𝑖
Where:
𝑖 is the 𝑖푡ℎ day of the survey
ℎ𝑖 is number of hours of survey for the 𝑖 day (5 hr < ℎ𝑖 < 10 hours)
푁𝑖 is the number of whales that passed the survey point during the ℎ𝑖 hours.
The mean 10-hour count (푅푣) for each year was calculated from all the daily 10-hour counts
(퐶𝑖, where 𝑖 = 1 to 퐷푣, and 퐷푣 = the number of days surveyed for year 푦). A simple linear regression was fitted to the natural log of the mean 10-hour count for each year (푅푦) over the survey period to determine the growth rate (percentage increase per year).
A growth model has also been fitted by generalised least squares. Full details of the growth model are shown in Appendix II.
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4.5 RESULTS
Between 1998 and 2004 a total of 105 days (897 hours, 45 minutes) of land-based surveys were conducted from Cape Byron. During this period a total of 1,768 pods, comprising 3,340 humpback whales (including 19 neonate calves) were observed travelling north past Cape Byron. Nineteen pods of humpback whales (1% of all pods seen), were observed to have a direction of travel other than in the general north direction (east, southeast or southwest). These pods were typically observed to be moving in a direction to interact with other pods of humpback whales. No pods were observed with a clear southerly migration direction during the survey. It is therefore assumed that, during the survey period all pods of humpback whales observed off Cape Byron have a clear northerly migration direction and therefore all pods were included in this analysis.
Most years of the CBWRP survey suffered from days with poor weather conditions and therefore not all days were surveyed. Other days were surveyed with below average conditions (such as rough seas) and have been eliminated from the analyses. Both 1999 and 2000 had a higher proportion of bad weather days than other years. Four days were lost due to rain in 1999 and another four days were removed because of rough seas or poor visibility.
Figure 4.1 indicates the increase in the mean number of whales observed per 10 hours for the seven years of the survey. Based on the fitting of a simple linear regression to the log of the mean 10-hour counts for the 16-day survey period, the annual growth rate for the humpback whale population was estimated to be 11% (95% CI 2.3–20.5, see Appendix II).
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Figure 4.1: Natural log of the mean 10-hour count by year with standard errors. A simple linear regression has been fitted.
The seven-year survey had large variations in the mean distance offshore of pods as shown in Figure 4.2. In 1998 and 2004, whales passed significantly closer to the Cape Byron survey station than other years except 2002 (p<0.05ANOVA, post hoc Bonferroni Test). The overall mean number of humpback whales in each pod was 1.9 ± 0.16 with slightly higher values in 1998 and 2004. The mean pod speed is reasonably consistent over years (Table 4.1). There was an increase in the number of newborn calves observed over the survey. The number of newborn calves observed annually, is approximately 0.5 to 1% of the total number of whales observed. Most pods had a composition of one (38%), two (43%) or three (12%) animals, while the rest of pods had between four to eight (7%) animals.
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Figure 4.2: Graph of the mean pod distance off shore and pod composition from 1998– 2004.
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Table 4.1: Yearly summary of data collected from Cape Byron Whale Research Project, 1998-2004. The average pod distance is the estimated distance from the coastline to the pod. The average pod speed is given in km/h, and distances are in kilometres.
Year Raw count 10-hr count ± Average pod Average Average No. of calves Max. pod size Max. SE size distance speed distance 1998 375 25.47 (±1.79) 2.12 2.52 6.49 0 5 (4 pods) 8.5 1999 229 23.38 (±2.75) 1.75 5.37 6.11 1 7 (1 pod) 13.6 2000 302 20.52 (±2.52) 1.88 4.45 5.88 0 5 (4 pods) 15.2 2001 522 32.33 (±2.62) 1.83 3.88 6.16 3 5 (1 pod) 18.4 2002 563 32.36 (±3.13) 1.88 3.85 5.70 3 8 (1 pod) 15.3 2003 505 32.12 (±2.09) 1.68 5.20 5.39 5 5 (2 pods) 16.6 2004 814 47.02 (±3.01) 2.03 2.93 6.20 7 8 (1 pod) 15.8
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4.6 DISCUSSION
The annual rate of increase between 1998 and 2004 for humpback whales observed off Cape Byron is calculated to be 11.0% (95% CI 2.3–20.5). This annual rate of increase is consistent with results recorded at Point Lookout, North Stradbroke Island (134 km north of Cape Byron) by two independent land-based surveys. Surveys conducted by Paterson (Paterson et al. 2004) estimate a growth rate of 10.5% per annum for the humpback whale population from 1984 to 2002. Other surveys conducted by Bryden et al. (1996) and Brown (1997) reported slightly higher annual rates of population recovery of about 12.3%. Brown et al. (2003) reassessed the Bryden/Brown data using more appropriate models and re-estimated the population increase (1981–2000) to be between 8.52% and 10.08%. However, Noad, continuing the Bryden/Brown surveys, reported a 10.6% (95% CI 10.1–11.1%) for the period 1987–2004 (Noad et al. 2011a) and an increase of 10.9% (95% CI 10.5–11.4%) for the period 1984–2007 (Noad et al. 2008). While these population growth rates lie near or above the theoretical reproductive maximum of the species (Best 1993; Brandao et al. 1999; Bannister and Hedley 2001; IWC 2008; Zerbini et al. 2011), which on the whole, are based on life history estimates for Northern Hemisphere humpback whale stocks where estimates for population growth rates are lower than determined for the Southern Hemisphere (IWC 2008), they are remarkably consistent over time with a very tight correlation between log- transformed, normalised whale counts and year (Noad et al. 2011a).
While this survey provides a useful estimate of population growth rate for the E1 Breeding Stock, there are several important considerations and some potential sources of bias that may influence the CBWRP estimate. There are several explanations for the observed variation in the number of whales counted per 10-hour period over the survey period:
1) There are large inter-annual variations in the number of humpback whales migrating up the east Australian coast;
2) Some of the surveys were influenced by bad weather or poor visibility conditions;
3) The short (16- day) survey missed some of the peak migration period in some years (potentially 1999, 2000 and 2003); and
4) Large variations in the average pod distance out to sea may lead to differences in their sightability.
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A degree of inter-annual variation is expected when monitoring a natural system. Forestell et al. (2003) suggested that El Niño-Southern Oscillation (ENSO) events may have a significant impact on fluctuations in whale numbers on the east coast of Australia. They suggested that humpback whales might migrate to other foraging areas in the high-latitude feeding grounds as a result of ENSO-related effects on food stocks. The whales might then migrate from there to different low latitude breeding grounds leading to variation in the number of whales observed between years. However, the long-term survey conducted by Paterson from North Stradbroke Island shows little variation in the overall humpback whale population count over the years (Paterson et al. 1994, 2001, 2004; Noad et al. 2011a,b); there is no indication of large fluctuations in the migrating population from year to year. Clapham and Zerbini (2006) have also suggested that the rapid growth rate of the E1 Breeding Stock may be a result of immigration from other populations. While these theories are plausible, the South Pacific Whale Research Consortium (SPWRC) recently tested this hypothesis by undertaking an assessment of fluke identification photographs collected throughout Oceania (Breeding Stocks E2, E3 and F) and eastern Australia (Breeding Stock E1). This analysis, coupled with the recovery of Discovery marks from this region, indicates a very low level of interchange between eastern Australia and the Oceania region, which does not support this theory (Paton and Clapham 2006; Garrigue et al. 2011a,b).
Brown et al. (1995) report a bias in the sex ratio of humpback whales sampled off the east coast of Australia. They suggest that not all animals migrate every year as there is little reason for females who are not calving or mating to make the long migration. This may mean that, depending on environmental conditions, there may be inter-annual variation in the proportion of females undertaking migration, which in turn may lead to variation in survey counts. As discussed in Chapter 1 there is potential for sampling bias associated with the methodology used by Brown et al. (1995). This issue remains unresolved with respect to EAH but has the potential to influence survey results between years. Sex ratio bias within the east Australian migrating population requires further investigation.
Environmental conditions during surveys can have a significant impact on the sightability of whales. Some of the years appear to have been influenced by poorer than average weather conditions. In particular, 1999 and 2000 were badly affected by rain and poor weather and a large number of survey days were lost. Throughout the survey the average for the 10-hour survey period was estimated only for those days with reasonable conditions. This should lead to an unbiased average from a smaller sample size but perhaps with a higher variance.
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Standardising effort between surveys in this manner should minimise any effect of environmental conditions on differences in whale counts between years.
The population growth estimate from this study is based on a maximum survey period of 16 days in any one year and represents an incomplete survey of the total migration period. While the assumption is that the weeks surveyed are representative of the full migration period, the accuracy of this assumption remains unknown. The survey was undertaken at the same time each year and studies of the timing of the migration have provided good evidence that migratory patterns are reasonably consistent between years, but the peak in migration may vary by up to a couple of weeks (Dawbin 1966; Paterson et al. 2001). It is therefore likely that the two-week survey period did not always capture the entire peak of the humpback migration each year. In order to investigate this, data from Cape Byron can be compared with data collected at North Stradbroke Island (134 km north of Cape Byron), which are collected over a much longer period. It takes almost one day for the humpback whales to travel from Cape Byron to North Stradbroke Island at an average speed of 6.0 km hr.
A comparison of 10-hour counts averaged on a weekly basis for the equivalent two weeks (e.g. accounting for the one-day travel time difference between the two sites) at Cape Byron and North Stradbroke Island can be seen in Figure 4.3. While there are fluctuations between the two sets of data, the Byron count is generally less than the Stradbroke count for most years except for 2001 and 2004 where the data are very similar. Figure 4.2 shows that the average pod distance is also much lower than most other years (except 1998). Because of the large variations in the Stradbroke weekly counts it is difficult to determine if the Cape Byron survey was conducted at the height of the peak migration period; it appears the peak migration often spans about a four-week period usually starting one week before the Cape Byron survey starts.
The distance at which the humpback whales pass Cape Byron varies considerably within and between years. All years of the Cape Byron survey except 1998 had observations of pods more than 10 km offshore and most years had observations of pods that were 15 km or more offshore. The estimated average percentage of pods that travelled more than 10 km offshore was 3.0% (range 0–16%); and the average for pods passing more than 5 km out was 35.0% (range 13.4– 53.0%). The author coordinated an independent vessel-based survey across the continental shelf off Cape Bryon in 1996 (CBWRP, unpublished data). This survey indicated that approximately 90% of humpback whales passing Cape Byron did so within
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10 km of the shoreline; the remainder travelling up to 23 km offshore. Had the CBWRP survey been conducted in 1998 or 2004 one would expect similar results to those of the present study; while quite different results would have most likely been obtained had the CBWRP study been completed in 1994 or 2003. Findlay and Best (1996a) found that between 40%–50% of whales travelling from 6–10 km offshore can be missed during counts. About 37% of whales were measured further than 6 km from the shoreline in 1999, 2000 and 2003. This implies there could be an error of about 18% in the counts for these years. Only ~10% of whales were observed more than 6 km from the shoreline in 1999 and 2004.
Figure 4.3: Cape Byron and North Stradbroke Island weekly 10-hour counts. The 1998 to 2002 North Stradbroke Island figures are from Paterson’s surveys (Paterson et al. 2001, 2004) and the 2004 North Stradbroke Island figures are from Noad et al. (2011a).
Two factors affect precision of the rate of growth calculated from the Cape Byron surveys:
(1) precision of 푅푦; and (2) number of survey years. Power calculations based on what is known about the migration patterns of this population could be conducted to determine whether annual surveys should be continued or whether a longer survey each second or third year would result in a greater improvement in precision per additional survey.
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The 2004 count may be viewed as an outlier as it appears to be inflated compared to other years. However, it may in fact be a more reliable count than most years due to good weather conditions and the average pod distance offshore being less than other years. In addition, 2004 was the last year of the survey period and therefore will have the highest count for this study due to the population growth rate and this will further exaggerate this perceived bias. Some of the other years of the survey (2000 and 2003) have low counts of humpback whales, which may have been a result of the greater average pod distance offshore and prevailing weather conditions. This may explain the difference between the growth rate calculated from the present study (11% 푅2 = 0.683) and the plausible IWC (2008) maximum biological increase of around 10.3%. A weighted least squares model can be used to improve the estimated growth rate of the humpback whale population by partly removing this bias. The weight (or variance) for each year’s 10-hour count (푅푦) could be based on the standard error for each day’s count (퐶𝑖) for that year. However the standard error generally increased with the increasing numbers of whales that passed each year, therefore the standard error for each year is divided by the average 10-hour count for that year to determine the normalised weight. The weighted least squares linear regression produced a growth rate of 10.1% with a slightly improved solution (푅2 = 0.713).
The data collected by the CBWRP may be better suited for detailed studies of humpback whale behaviour patterns. The data may also be useful in studying the cause and effect of variables that influence observing conditions. A number of different relationships between pod behaviour and distribution patterns along with other factors that influence viewing conditions can be further studied.
4.7 ACKNOWLEDGEMENTS
The CBWRP was a large undertaking each year and was not possible without the help of a number of people. Many thanks go out to Guy Holloway, Sue Walker and Bob Beale from the NSW National Parks and Wildlife Service, and Nick Rigby formerly from the Cape Byron Trust, for their help and co-operation with running the survey from the Cape Byron headland and lighthouse. Our gratitude is also extended to staff from Southern Cross University/Southern Cross University Whale Research Centre, especially Professors Peter Baverstock and Peter Harrison, for their assistance with organising the surveys. Additional support from Robyn McCulloch (Department of Environment and Heritage), Mike Noad, Doug Cato, John Sugarman (AMSA), Wayne Pellow, Steve King, Mark Johnson (NSW
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NPWS), and Ted Taylor (Cape Byron Coastal Patrol) is also much appreciated. Constructive comment on the draft manuscript was received from Peter Baverstock, Simon Childerhouse and two anonymous reviewers. Lyndon Brooks provided statistical advice and assistance with the growth model used in Appendix II.
Special thanks goes out to all the volunteers especially Merv Wicker, Adrian Oosterman, Dan Burns, Megan Anderson, Wendy Stewart, Simon Walsh, and Grant Baker for their expert assistance over many years of the survey. And the authors are very grateful to all the partners of all the volunteers and organisers, especially Susanne Paton and Elizabeth Kniest.
The CBWRP was undertaken under a Scientific Research Permit issued by the Department of the Environment, Water, Arts and Heritage under the Environment Protection and Biodiversity Conservation Act 1999 (permit number E2001/0005) and the New South Wales National Parks and Wildlife Service (permit number S10403).
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CHAPTER 5 ABUNDANCE OF EAST COAST AUSTRALIAN HUMPBACK WHALES (MEGAPTERA NOVAEANGLIAE) ESTIMATED USING MULTI-POINT SINGLE-YEAR (2005) SAMPLING AND CAPTURE-RECAPTURE ANALYSIS3, AND MULTI-YEAR SINGLE-POINT SAMPLING AND CAPTURE- RECAPTURE ANALYSIS (1999-2005)4
5.1 ABSTRACT
The humpback whales (Megaptera novaeangliae) that migrate along the east coast of Australia were hunted to near extinction during the last century. This remnant population is part of Breeding Stock E. Previous abundance estimates for the east Australian portion of Breeding Stock E have been based mainly on land-based counts. Here we present capture-
3 This paper is published as: Paton DA, Brooks L, Burns D, Franklin T, Franklin W, Harrison P, Baverstock P (2011). Abundance of East coast Australian humpback whales (Megaptera novaeangliae) in 2005 estimated using multi-point sampling and capture-recapture analysis. Journal of Cetacean Research and Management (Special Issue) 3, 253–259. Refer to Appendix III for a direct reprint of this paper. Copyright permission from the journal has been obtained. A statement of contributions to this paper is included in section 1.5.3.
4 This report appears as: Paton DA, Brooks L, Burns D, Kniest E, Harrison P, Baverstock P (2009). Abundance estimate of Australian East Coast humpback whales (Group E1) in 2005 using multi-year photo-identification data and capture-recapture analysis. Report SC/A06/HW33 submitted to the Scientific Committee of the IWC. 11pp. A statement of contributions to this paper is included in section 1.5.3.
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recapture abundance estimates for this population using photo-identification data and two different methodologies.
The first is a multi-point single-year capture-recapture assessment using photo-identification data collected at three locations on the migration route (Byron Bay – northern migration, Hervey Bay and Ballina – southern migration) in order to estimate the population of humpback whales that migrated along the east coast of Australia in 2005. These capture- recapture data were analysed using a set of closed population models with a model-averaged estimate of 7,041 (95% CI 4,075–10,008) humpback whales.
The second methodology was a multi-year single-point photo-identification capture- recapture analysis undertaken on data collected at Byron Bay over seven years (1999-2005). This analysis resulted in a population estimate for the number of humpback whales that migrated north past Byron Bay in 2005 of 7,390 (95% CI: 4,040-10,739).
These estimates are consistent with land-based estimates for Group E(1) and support the growing body of data that indicate a high rate of increase for this population of humpback whales.
5.2 INTRODUCTION
Humpback whales (Megaptera novaeangliae) in the Southern Hemisphere undertake an annual migration during the austral winter months from their Antarctic feeding areas in higher latitudes to their tropical breeding areas (Chittleborough 1965; Paterson 1991). There is temporal segregation of different classes of whales on this migration, with lactating females and yearlings the first to leave the feeding grounds, followed by immature whales of both sexes, mature males and resting females, and lastly pregnant females migrating to the breeding grounds (Dawbin 1966, 1997). On the return journey to the Antarctic feeding grounds, newly pregnant females are the first to leave tropical waters, followed by immature whales, mature males and resting females, and lastly mothers with calves (Dawbin 1966, 1997). Chittleborough (1965) concluded that the population of humpback whales that migrate along the east coast of Australia comprises part of the Area V population (130º0’E to 170º0’W). This population was previously known as Group V. Recent studies suggest that the region contains several populations that intermingle to a variable but probably small degree (Garrigue et al. 2000, 2011a). Group V humpback whales have now been divided into three sub-stocks known as Breeding Stock E1, those wintering off the Australian east
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coast; E2, those wintering around New Caledonia; and E3, those wintering around Tonga (Bannister 2005; Olavarría et al. 2006). Breeding Stock E1, the Australian east coast population, is thought to be the largest of these.
Last century, the Area V humpback whale population was subjected to both land- and vessel-based hunting from a number of locations throughout its migratory range, including the east Australian coastline and Antarctica. Prior to the 1950s there was little exploitation of this east Australian population. At this time the population size of the entire Group V population was estimated to be between 10,000 and 26,000 whales (Chittleborough 1965; Bannister and Hedley 2001). However, these figures are potentially an underestimate of the pre-exploitation population for Group V. The total number of 20th Century and post World War II humpback whale catches in Area V and their purported breeding area (E) was 64,252 (Clapham and Zerbini 2006) and 38,146 respectively (Clapham et al. 2005). Jackson et al. (2008) estimate the pre-exploitation size of the East Australian humpback whale (EAH) population to have been 22,000-25,700 and the combined Oceania populations (E2, E3 and F) to be 17,800-26,600.
Massive illegal pelagic whaling in the Southern Ocean, coupled with industrial shore-based whaling, resulted in a major population collapse by 1962 (Chittleborough 1965; Clapham et al. 2005). Estimates of the remaining population varied from 104 for all of Group V (Bannister and Hedley 2001) to 500 for the east Australian and New Zealand populations (Chittleborough 1965). Further modelling of the catch data by Jackson et al. (2009) has determined that the EAH population reached an all-time low in 1968, with minimum abundance estimated at between 190 and 205 animals. This represents less than 5% of the original estimated EAH population.
Land-based surveys undertaken from Point Lookout on North Stradbroke Island following the cessation of commercial whaling activities on the east coast of Australia in 1963 indicated that there was virtually no recovery in this population of whales until the 1970s (Paterson and Paterson 1984). It was not until the period of 1978-1982 that any positive signs of recovery were detected (Patterson and Patterson 1984). Since this time EAH have shown signs of partial recovery (Paterson et al. 2001; Brown et al. 2003; Noad et al. 2008, 2011a). The apparent lack of recovery of the humpback whale population migrating past New Zealand (Gibbs and Childerhouse 2004; Constantine et al. 2006), and low numbers recorded in some regions of the South Pacific (Garrigue et al. 2000, 2002; Paton et al. in
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review), suggest that most of the humpback whales remaining in Area V at the termination of whaling probably form the EAH population. It is important to note, however, that satellite tracks from tagged humpback whales indicate that a small percentage of whales that feed in Area V migrate to breeding grounds in Oceania and not eastern Australia (Gales et al. 2009). The most recent abundance estimate for the EAH population utilised land-based counts at North Stradbroke Island, Queensland, with an estimate for the 2004 season of 7,090±660 (95% CI) (Noad et al. 2011a). However, all methods of estimating abundance have inherent assumptions and biases. Therefore, a more robust population estimate can be obtained by using a number of techniques.
Recent estimates of adult survival rate for humpback whales include figures of 0.95 for the Gulf of Maine population (Buckland 1990, Clapham et al. 2003) and 0.96 for populations in the North Pacific Ocean (Calambokidis and Barlow 2004, Mizroch et al. 2004).
The technique of identifying individual humpback whales by photographing the underside of their tail flukes is widely accepted (Katona et al. 1979; Hammond et al. (eds) 1990), and has been used extensively for capture-recapture analyses to estimate population parameters and abundance (Hammond 1986; Buckland 1990; Calambokidis et al. 1990; Smith et al. 1999; Urbán et al. 1999; Calambokidis and Barlow 2004).
This study represents capture-recapture population estimates for the portion of the humpback whale Breeding Stock E, which migrates along the east coast of Australia. To date, most of the estimates of the abundance of the EAH migration have been based on simple counts and distance sampling methods. The population estimates presented in this chapter are based on an analysis of an ongoing dataset of photo-identification data collected by the authors. We have used the 2005 photo-identification data to establish a point of reference for future photo-identification studies and to provide a point comparison of estimates obtained independently by distance sampling and capture-recapture methods.
In addition to current data on the population trend presented in Chapter 4, a current population estimate is important information required for the Comprehensive Assessment of Southern Hemisphere Humpback Whales (CASH) process undertaken by the IWC. The research undertaken in this chapter provides two population estimates based on photo- identification capture recapture methods. The first estimate is a multi-point single-year (2005) population estimate using photo-identification data collected at Byron Bay, Hervey
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Bay and Ballina. The second estimate is a multi-year single-point population estimate using photo-identification data collected at Byron Bay between 1999 and 2005.
The information in this chapter is partly based on a paper presented to the IWC intercessional meeting in Hobart to undertake a CASH (Paton A, Brooks L, Burns D, Franklin T, Franklin W, Harrison P, Baverstock P (2006) First abundance estimate of east coast Australian humpback whales (Megaptera novaeangliae) utilising mark-recapture analysis and multi- point sampling. Unpublished IWC paper SC/A06/HW32). A manuscript with revisions from that presented in Hobart has been published as Paton A, Brooks L, Burns D, Franklin T, Franklin W, Harrison P, Baverstock P (2011) Abundance of East Coast Australian humpback whales (Megaptera novaeangliae) in 2005 estimated using multi-point sampling and capture-recapture analysis. Journal of Cetacean Research and Management Special Issue 3 ‘Humpback Whales: Status in the Southern Hemisphere’: 253-259.
This chapter also draws upon Paton DA, Brooks L, Burns D, Kniest E, Harrison P, Baverstock P (2009). Abundance estimate of Australian East Coast humpback whales (Group E1) in 2005 using multi-year photo-identification data and capture-recapture analysis. Report SC/A06/HW33; a report submitted to the Scientific Committee of the IWC.
5.3 METHODS
5.3.1 Multi-point single-year capture-recapture
Study areas and survey effort Three sampling sites were used on the humpback whale migratory corridor on the east coast of the Australian mainland: Byron Bay in northern New South Wales (NSW); Hervey Bay in Queensland (approximately 450 km north of Byron Bay); and Ballina in northern NSW (approximately 25 km south of Byron Bay). All three sites are the locations for long-term independent studies by four of the authors (DP, DB, TF, WF5) on the biology, behaviour and population characteristics of EAH.
Vessel-based photo-identification surveys were undertaken as humpback whales migrated past each of the study sites within one migratory season during the 2005 austral winter and spring months (June–November 2005). Field surveys at each of the study sites were timed to include the major part of the migration on either side of the peak past that location
5 DP = David Paton; DB = Daniel Burns, TF = Trish Franklin, and WF = Wally Franklin. Page 100
(Paterson 1991; Dawbin 1997). Due to the timing of the migration and the locations of the three study sites on the migration corridor, surveys commenced first at Byron Bay during the northern migration, followed by surveys in Hervey Bay and Ballina on the southern migration. There was limited temporal overlap (six days) between sampling during the northern migration at Byron Bay and the commencement of sampling in Hervey Bay during the southern migration. Surveys at Hervey Bay and Ballina were undertaken mostly concurrently during the southern migration. Geographical location, survey effort and equipment used are summarised in Table 5.1.
The study sites of Byron Bay and Ballina are on the migratory corridor at, or close to, the most easterly point of the Australian mainland, where the vast majority of humpback whales migrate within 10 km of the coast (Bryden 1985). The width of the humpback whale migration corridor was re-assessed in 1991 (Brown 1997) and 2007 (Noad and Dunlop 2007), and found to be consistent with the results of Bryden (1985). Humpback whales travel past Ballina and around the eastern point of Australia at Byron Bay, in both a northerly and southerly direction, en-route between the Antarctic feeding grounds and the Great Barrier Reef breeding grounds (Paterson 1991). At Byron Bay and Ballina, the research vessel was assisted in finding pods of whales by a team of land-based observers using the ‘Cyclopes’ (theodolite/computer) whale tracking system (Kniest and Paton 2001a,b).
The third study site is located in Hervey Bay, a sheltered, shallow bay formed between the Queensland coast and Fraser Island, 60 nm below the southern end of the Great Barrier Reef. During the southern migration, many humpback whales travel into and out of the eastern side of Hervey Bay from the north. The distance between Hervey Bay and the Byron Bay and Ballina study area is approximately 450 km (Figure 5.1).
A standard sampling protocol for photo-identification was adopted for each sampling site. Photography of ventral fluke surfaces was obtained during a maximum of ten terminal dives and/or a maximum of 45 minutes with each pod (Smith et al. 1999). Photographs of the ventral fluke surface of calves were not included in this study. All images were cropped to a common 3 × 2 pixel ratio as high quality .jpeg digital files.
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Table 5.1: Summary of locations, survey effort and equipment utilised for multi-point single-year capture-recapture analysis of photo- identification data (2005).
Byron Bay Hervey Bay Ballina Migration direction North South South Latitude/longitude 28°37’ S, 153°38’ E 25°00’ S, 153°00’ E 28°52’ S, 153°37’ E General geography Open ocean off most easterly Shallow, sheltered bay close to Open ocean off Ballina and point of Australian mainland western shore of Fraser Island Lennox Head Dates of survey 04/06/05 to 12/08/05 07/08/05 to 14/10/05 17/08/05 to 04/11/05 Survey period 69 68 79 Number of survey days 50 60 39 Daily effort (Av. hours per day) 7 hours 56 minutes 7 hours 20 minutes 6 hours 32 minutes Research vessel 5.4-metre centre console 12-metre power catamaran 5.8-metre centre console powerboat powerboat Photographic equipment Canon EOS 20D, 100–400mm Canon EOS 20D, 100–300mm Nikon D100, 70–200mm lens lens F3.5–5.6 L IS lens F3.5–5.6 F2.8 VR, and 1.4X converter Supported by land-based Yes No Yes spotters Principal photographer DP TF DB
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Figure 5.1: Study areas for multi-point single-year capture-recapture analysis of photo- identification data (2005).
Photo-identification analysis The principal photographers examined all images for each of their respective study sites and selected the best single photograph for each individual whale. Composites of multiple images of a single fluke were constructed if these provided sufficient information to accurately identify the whale (see Figure 5.2). All images for each study site were assessed for within-season resights to eliminate duplicates. Where duplicates were detected the best image was kept of each individual whale.
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Figure 5.2: Example of a composite image used in analysis.
In order to produce the final dataset for analysis, the principal photographers then collectively reviewed the fluke catalogue for each sampling site using a protocol developed in the northern hemisphere for grading humpback whale fluke identification photograph quality (Calambokidis et al. 2001). This included scoring all flukes according to five different characteristics of photo quality: (1) exposure/contrast/lighting; (2) fluke angle; (3) photographer/lateral angle; (4) focus/sharpness; and (5) proportion of fluke visible. Each photograph was given a score from 1 to 5 (highest quality to lowest) for each characteristic, and all flukes with at least one score of 4 or 5 were excluded from the dataset.
Prior to matching, each of the principal photographers stratified their catalogue according to one of two independently-evolved fluke matching systems: the Byron Bay and Ballina fluke catalogues were stratified using a system developed by one of the authors (DB), while the Hervey Bay catalogue was stratified using a system developed by another author (TF). The stratified matching systems used in this analysis are based on individual fluke characteristics including percentage black, characteristics of the centre and characteristics of the trailing edge of the fluke for each identification photograph. These systems were used to reduce the number of comparisons required in the matching process.
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Pair matching using digital images was conducted by two independent matchers for each site as follows: DB matched Ballina against the Byron Bay and Hervey Bay Catalogues; DP matched Byron Bay against the Ballina and Hervey Bay Catalogues; and TF matched Hervey Bay against the Byron Bay and Ballina Catalogues. All matched flukes, including matches found by only one of the two matchers, were collectively reviewed and reconciled.
Statistical models Our approach to estimation assumed that the population was closed to immigration, emigration, births and deaths during the sampling period and that images of the same individuals were reliably matched (that is, no tag loss). After assessing the credibility of the closure assumption and the likelihood of tag loss, we considered a number of different assumptions about the sources of variation in capture and recapture probabilities that might be incorporated in models; whether capture probabilities varied by occasion (temporal variation), differed on any occasion between previously captured and newly captured individuals (behavioural response) or varied among individuals (heterogeneity). The program CAPTURE (Otis et al. 1978; Rexstad and Burnham 1992) was employed to provide an initial indication of the most likely sources of variation. Finally, the program MARK (Version 5.0: www.phidot.org/software/mark/) was employed to fit and compare a set of credible models.
Population closure The data were collected within one migratory cycle (within a 6-month period). It is assumed that whales migrating north past Byron Bay during the northern migration of 2005 returned south to the feeding grounds along the east coast of Australia during the southern migration and were potentially available for capture at Hervey Bay and/or Ballina. This assumption is supported by a study of genetic diversity (Olavarría et al. 2006), an analysis of interchange rates between eastern Australia and Oceania based on photo-identification (Garrigue et al. 2011b) and within-season returns of Discovery marks in the region (Dawbin 1964). Deaths, immigration and emigration were assumed to have had negligible effects on the estimate. Calves were not included in this analysis, thereby eliminating the effects of births or calf mortality. Therefore, for the purposes of this analysis, the population was considered to be closed.
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Tag loss Effective tag loss resulting in an overestimate of the population size may have occurred in this study if flukes changed markings between sampling occasions, and might have occurred if poor quality, difficult-to-match photographs had been included. Significant changes in natural fluke markings are likely to have been minimal during the short survey period. The use of a widely accepted protocol, based on photo quality (Calambokidis et al. 2001), minimises the potential for tag loss due to poor image quality.
A further source of effective tag loss may be human error in failing to match fluke photographs. By using two independently evolved stratification systems and having two independent matchers each separately conduct the match for each site, before reconciling the results, the probability of missing a match is considered to be low.
Time-specific capture probabilities Survey effort varied among the sites (Table 5.1) with approximately 397, 440 and 255 survey hours at Byron Bay, Hervey Bay and Ballina respectively. Environmental conditions, vessel speeds and survey protocols also varied slightly. It is highly likely, therefore, that capture probabilities were variable among the sites and lower at Ballina than at the other two sites in particular.
Behavioural response Whilst there is no reason to expect that whales either sought or avoided the survey vessels following capture, there is reason to consider it possible that apparent behavioural response was present in the data due to non-random mixing between samples. Dawbin (1966; 1997) reported that the migration is structured in a temporal sequence led by lactating females and yearlings, immature whales of both sexes, mature males and resting females, and lastly pregnant females migrating to the breeding grounds. This sequence is largely the same during the migration south, with newly pregnant females the first to leave the breeding grounds, followed by immature whales, mature males and resting females, and lastly mothers with calves (Dawbin 1966, 1997). Although the surveys were timed to spread across a sizeable part and centred on the expected peak of the migration past each of the sites, it is possible that such classes of whales were not present in the same proportions during the survey periods at the three sites. Under these circumstances, the whales captured at a site may be more or less prevalent with probabilities of recapture at subsequent sites that differ from the probabilities of first capture at those sites, inducing apparent behavioural response.
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Heterogeneity of capture probabilities The probability of capture of a whale is conditional on the time it is available for capture at a site, its response to vessels and its fluking behaviour. The typical time spent in the presence of vessels and the typical frequency and duration of fluking activity may vary among such classes of whales as immature whales, mature resting females, mature males and mothers with calves (Rice et al. 1987). Following the previous example, mothers with calves may be more or less likely to fluke up than other whales and indeed may typically spend a shorter or longer period in Hervey Bay. There is no evidence of a differential in the probability of a whale fluking between the northern and southern migration, however, this issue has not been fully investigated. Therefore, heterogeneity of capture probabilities is possible.
Tests of assumptions and goodness of fit The seven tests from program CAPTURE (Otis et al. 1978; Rexstad and Burnham 1992) were run to gain insight into a likely appropriate model structure. However, given the potential complexity of the data-generating process and a high probability of time-specific capture probabilities, it is notable that CAPTURE provides no tests for the pertinent comparisons of 푀푡 vs 푀푡ℎ or 푀푡 vs 푀푡푏.
The full likelihood-based closed capture models available in the program MARK (Version 5.0: www.phidot.org/ software/mark/) provide a means of fitting a number of models of the forms 푀푡 and 푀푡푏 (Otis et al. 1978). These models were compared by means of the minimum AICc criterion (Williams et al. 2002), and estimates from a set of selected models were averaged following the procedure of Buckland et al. (1997). Modelling was restricted to these models except for the non-likelihood based 푀푡ℎ model of Chao et al. (1992), which was employed to provide an informal comparison of its estimate to those from the 푀푡 and
푀푡푏 models referred to above.
5.3.2 Multi-year single-point capture-recapture
Study areas and survey effort Vessel-based photo-identification surveys were undertaken annually at Byron Bay (the same study site for the Byron Bay component of the multi-site analysis) between 1999 and 2005 (Figure 5.3).
Surveys were undertaken as whales migrated north past Cape Byron during the austral winter months (May-August). Survey effort was not consistent for each field season between
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1999 and 2005, and while the annual surveys were timed to include what was anticipated to be the peak of the northern migration passing Byron Bay, based on historical and recent data (Paterson 1991; Dawbin 1997; Paton and Kniest 2011), most annual surveys covered only a short part of the migration period.
The research vessel was assisted in finding pods of whales by a team of land-based observers working from Cape Byron lighthouse using the ‘Cyclopes’ (theodolite/computer) whale tracking system (Kniest and Paton 2001a,b). Survey effort, timing and equipment used during each annual survey are summarised in Table 5.2.
Fluke photography was obtained using a standard sampling protocol throughout the duration of the project as described in section 5.3.1 above.
Figure 5.3: Study area for multi-year single-point capture-recapture analysis of photo- identification data (1999-2005).
Photo-identification analysis The single best photograph for each individual whale for each field season was selected. Non digital images were scanned using a Nikon Coolscan III at maximum resolution. All images were cropped to a common 3 x 2 pixel ratio as high quality jpeg digital files.
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Composites of multiple images of a single fluke were constructed if these provided sufficient information to accurately identify the whale (Figure 5.2). All images for each field season were assessed for within-season resights to eliminate duplicates.
In order to address potential bias associated with photo quality, an independent cetacean researcher experienced in humpback whale fluke photograph matching, reviewed the fluke catalogue using a protocol developed in the Northern Hemisphere for grading humpback whale fluke identification photograph quality (Calambokidis et al. 2001). This included scoring all flukes according to five different characteristics of photo quality: (1) exposure/contrast/lighting; (2) fluke angle; (3) photographer/lateral angle; (4) focus/sharpness; and (5) proportion of fluke visible. Each photograph was given a score from 1 to 5 (highest quality to lowest) for each characteristic, and all flukes with at least one score of 4 or 5 were excluded from the dataset.
Table 5.2: Summary of survey effort and equipment used to collect the multi-year single-point photo-identification analysis of photo-identification data.
Year 1999 2000 2001 2002 2003 2004 2005 Dates of survey 19 – 20 25 June – 23 June – 17 June – 21 June – 26 June – 4 June – 12 June, 30 9 July 8 July 20 July 6 July 11 July Aug June – 11 July Survey period 14 14 16 34 16 16 69 (days) Research vessel 5.8-metre 5.8-metre 5.8-metre 5.8-metre 5.8-metre 5.8-metre 5.5-metre centre centre centre centre centre centre centre console console console console console console console Photographic Canon Canon Canon Canon Canon Nikon Canon equipment EOS 1, EOS 1, EOS EOS EOS D100, 70- EOS 20D, 300mm 300mm 10D, 10D, 10D, 200mm 100- lens F2.8 lens F2.8 100- 100- 100- lens F2.8 400mm 400mm 400mm 400mm VR and lens F3.5- lens F3.5- lens F3.5- lens F3.5- 1.4x 5.6IS 5.6IS 5.6IS 5.6IS converter
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Matching A stratified matching system developed by one of the authors (DB) was used in this analysis. This system is based on stratifying flukes by different characteristics including percentage black, characteristics of the centre and characteristics of the trailing edge of the fluke for each identification photograph. This system was used to reduce the number of comparisons required in the matching process. All matches found were reviewed and confirmed by at least two of the authors (DP and DB).
Statistical model Only the 2005 sample, which extended over a large part of the total migration (a 10-week survey period), might be considered to be a random sample from the migrating population. The samples in the years 1999 to 2004 would have been selected from the classes of whales passing Byron Bay in the relatively short periods of the surveys in those years. This is unlikely to have been the same part of the population each year because a) the peak of the migration can change by up to five weeks from year to year (Dawbin 1956a), and b) some whales are likely to have changed age class or pregnancy status between years, and therefore the timing of their migration.
The series of surveys describes an open population with births, mortality, potential immigration and emigration occurring between years. However, no specific open population model framework is available that is able to meet all the biological features of this population given its complexity and spatial coverage. Since a suitable open population model was not available, a simpler model was selected as being appropriate for use.
We used the Chapman small sample modification to the Lincoln-Petersen two sample estimator for N (see Chao and Huggins 2005 for example) based on a sample pooled over the years 1999 to 2004, and compared with the 2005 sample. This is a consistent estimator of the population size when either or both of the samples are a simple random sample as we assumed for the 2005 sample (see Schwarz 2005). We adjusted the number marked in the pooled sample (푛1) to the number expected to have been alive and available for resighting in 2005 (푛1퐴) by reducing the count from the year last sighted assuming a true survival rate of 0.95 pa. This procedure adjusted for the mortality between marking and recapture. Births and permanent immigrants in the interval 1999 to 2005 would have been represented in the 2005 sample. There was no basis on which to make any adjustment for permanent emigrants.
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The Chapman estimator of population size (푁̂):
(푛 + 1)(푛 + 1) 푁̂ = 1 2 − 1 (푚2 + 1)
(푛 + 1)(푛 + 1)(푛 − 푚 )(푛 − 푚 ) 푉푎푟(̂푁) = 1 2 1 2 2 2 (푚2 + 1)(푚2 + 2) where,
푛1 = number identified in first sample;
푛2 = number identified in second sample; and
푚2= number common in both samples.
5.4 RESULTS
5.4.1 Multi-point single-year capture-recapture
A total of 1,085 fluke photographs were assessed for inclusion in the analysis (Byron Bay 406, Hervey Bay 391, Ballina 288). Following collective evaluation of each image against the photograph quality protocols, 222 fluke photographs were excluded from the dataset based on photographic quality. The final dataset comprised a total of 863 fluke photographs (Byron Bay 343, Hervey Bay 321, Ballina 199). Of these, 829 whales were determined to be unique individuals, with a total of 34 (4.1%) whales being captured at two different survey sites during the study period. No whales were sampled at all three survey sites within the study period. Within season resights did occur at individual study sites. Where this did occur only the best image of an individual whale from each study site was included in the analysis. At Byron Bay resights only occurred within the same sampling day. See Burns (2010) Burns et al. (2014) and Franklin (2012) for details for within season resights of individual whales at Ballina and Hervey Bay. The matches and frequencies of capture histories are reported in Table 5.3.
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Table 5.3: Frequencies of capture histories for multi-point capture-recapture photo- identification data.
Byron Bay Hervey Bay Ballina Frequency 1 0 0 319 0 1 0 297 0 0 1 179 1 1 0 14 1 0 1 10 0 1 1 10 1 1 1 0
Tests of the assumptions The goodness of fit tests from program CAPTURE (Otis et al. 1978; Rexstad and Burnham
1992) indicated probable behavioural response (test 2: 푀0 vs. 푀푏), probable time-specific variation in capture probabilities (test 3: 푀0 vs. 푀푡), probable heterogeneity in capture probabilities (test 4: 푀ℎ vs. not 푀ℎ), probable behavioural response (test 5: 푀푏 vs. not 푀푏), and probable behavioural response in the presence of heterogeneity (test 7: 푀ℎ vs. 푀푏ℎ). The expected values were too small to test for heterogeneity (test 1: 푀0 vs. 푀ℎ) or time-specific variation (test 6: 푀푡 vs. not 푀푡). CAPTURE suggested that the appropriate model was probably 푀푡푏 but encountered a computational problem in trying to fit the model and did not produce a reliable estimate (offering 28581).
Among the set of eight full and reduced 푀푡 and 푀푡푏 likelihood based models (Otis et al. 1978) that might notionally be fitted, it was not possible to simultaneously estimate the six parameters of the most general of these models with different capture probabilities at each site and recapture probabilities different both to each other and any capture probability. This is because at least one constraint relating the capture and recapture probabilities is required for identification. Among the remaining seven models of this type, a model that proposed equal capture probabilities in Byron Bay and Hervey Bay and that the two recapture probabilities differed both from each other and from any capture probability also lacked the required constraint and produced an unrealistically low estimate of population size (3,059). Pertinent results from the remaining six models are reported in ascending order of AICc in Table 5.4.
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Among a small set of models that assumed equal capture probabilities, the best fitting
(111234) had an AICc that was 5.59 larger than the worst fitting of the 푀푡 and 푀푡푏 models in Table 5.4 (123245) indicating, as expected, a high probability of time-specific variation in capture probabilities.
For comparison with the estimates provided by this set of models, the 푀푡ℎ model (Chao et al. 1992) from program CAPTURE provided an estimate of 7,014 (95% CI 5,163–9,685) with equal probabilities of capture off Byron Bay and in Hervey Bay.
Model selection The deviances of these models were very similar and the minimum AICc criterion accordingly ordered the models largely in terms of parsimony; that is, it favoured models with fewer parameters. Although c-hat could not be estimated, an experiment in which its value was assumed to be 2 resulted in the more parsimonious models being even more strongly favoured in terms of relative AICc values.
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Table 5.4: Results from six full and reduced 푀푡 and 푀푡푏 models for multi-point single-year capture-recapture photo-identification data.
Model1 AICc ΔAICc AICc wt. Likelihood Params. Deviance Nhat SE L95%CI U95%CI 112123 –7417.436 0.000 0.340 1.000 3 10.462 7,024 1,139 5,163 9,685 1232342 –7416.195 1.241 0.183 0.538 4 9.697 7,021 1,138 5,160 9,680 112324 –7416.033 1.403 0.169 0.496 4 9.859 6,303 1,298 4,290 9,486 112134 –7415.775 1.662 0.148 0.436 4 10.118 7,843 2,007 4,876 12,985 123435 –7414.554 2.883 0.081 0.237 5 9.330 6,447 1,346 4,365 9,754 123245 –7414.528 2.908 0.079 0.234 5 9.356 7,834 2,005 4,871 12,971
1 The models are numbered according to their parameters: capture probabilities in Byron Bay, Hervey Bay and Ballina, recapture probabilities in Hervey Bay and Ballina, and the estimated population size. Where a subsequent parameter is specified as equal to a previous one, the previous parameter number is used. For example, model 112123 indicates the same capturet probabilities in Byron Bay (1) as in Hervey Bay (1) but a different capture probability off Ballina (2); that the recapture probability in Hervey Bay is the same as the capture probability in Hervey Bay (= Byron Bay) (1), and that the recapture probability off Ballina (2) is the same as the capture probability off Ballina (2). The population estimate parameter takes the next value (3).
2 Darroch 푀푡
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Population estimate The range of population estimates (6,303–7,843) among the models reported in Table 5.4 was not wide relative to the width of the confidence intervals. Consequently, the considerable uncertainty encountered in selecting among the models on the basis of AICc was not as serious a limitation on obtaining a reasonable estimate as it might otherwise have been. However, if only one of these models were to be chosen for interpretation it would be the simplest, with a likelihood nearly twice the size of that of the next most likely model; that is, the 3-parameter model (112123), which assumed equal capture probabilities at Byron Bay and in Hervey Bay, and recapture probabilities equal to capture probabilities (no behavioural response). Further in favour of this model, if overdispersion were present in the data, as would be reflected in a higher c-hat, its likelihood would have been even greater relative to the other models. This model provided an estimate of 7,024 (95% CI 5,163–9,685) whales, which lies approximately in the middle of the range of the several estimates. Nonetheless, while apparent behavioural response cannot be excluded theoretically, and the four models in the set that do assume some form of apparent behavioural response cannot be reliably distinguished among nor from the simpler models by the AICc criterion, it may be appropriate to use the very similar model-averaged estimate of 7,041 (95% CI 4,075– 10,007) whales.
None of the models considered so far has treated animal level heterogeneity of capture probabilities. As a point of reference, the 푀푡ℎ model of Chao et al. (1992) provided an estimated population size of 7,014 (95% CI 5,133–9,718) whales.
5.4.2 Multi-year single-point capture-recapture
Table 5.2 describes the survey dates for the years 1999 to 2005. Only the 2005 survey extended over a relatively large part (approximately 12 weeks) of the migration period.
A total of 1,008 fluke photographs were assessed for inclusion in the analysis. Following independent assessment against photograph quality protocols, 243 fluke photographs were excluded from the dataset based on photographic quality. The final dataset comprised a total of 765 fluke identification photographs. Table 5.5 reports the matches and frequencies of capture histories. Table 5.6 reports the number of whales sighted between 1999 and 2004
(푛1) and the number of those expected to have been alive and available for capture in 2005
(푛1퐴) based on an assumed mortality rate of 5%.
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Three hundred and thirty seven (337) whales were sighted in 2005 (푛2) of which 15 had been previously sighted at least once in the period 1999-2004 (푚2). The Chapman estimate of the population size in 2005 (푁̂|푛1, 푛2, 푚2) was 8,850 (95% CI: 4,823-12,878) whales.
The mortality-adjusted Chapman estimate of the population size in 2005 (푁̂|푛1퐴, 푛2, 푚2) was 7,390 (95% CI: 4,040-10,739) whales.
Table 5.5: Matches and frequencies for capture histories of humpback whales recorded near Byron Bay, Australia for the multi-year single-point capture-recapture photo-identification data.
The ‘Row’ number indicates the event. The columns ‘1999’ – ‘2005’ indicates the year of the sample and the column ‘n_row’ indicates the number of individual whales identified that year for rows 1 – 7 or the number of individual whales recaptured and in what year in rows 8 - 19.
Row 1999 2000 2001 2002 2003 2004 2005 n_row 1 1 0 0 0 0 0 0 32 2 0 1 0 0 0 0 0 32 3 0 0 1 0 0 0 0 64 4 0 0 0 1 0 0 0 103 5 0 0 0 0 1 0 0 61 6 0 0 0 0 0 1 0 101 7 0 0 0 0 0 0 1 322 8 1 0 0 1 0 0 0 1 9 1 0 0 0 0 1 0 1 10 1 0 0 0 0 0 1 1 11 0 1 0 1 0 0 0 1 12 0 0 1 1 0 0 0 1 13 0 0 1 0 1 0 0 1 14 0 0 0 1 1 0 0 1 15 0 0 0 1 0 1 0 1 16 0 0 0 1 0 0 1 7 17 0 0 0 0 1 1 0 3 18 0 0 0 0 1 0 1 2 19 0 0 0 0 0 1 1 5
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Table 5.6: Number of sampled humpback whales estimated to be alive in 2005 based on an estimated 0.95 population survival rate for the multi-year single-point capture-recapture photo-identification data.
Year n-last sighted Estimated n-alive in 20051 1999 32 23.52 2000 32 24.76 2001 64 52.13 2002 106 90.88 2003 63 56.86 2004 106 100.70
1999-2004 푛1 = 403 푛1퐴 = 348.85
1 Calculated as (n-last sighted)*(0.95)(2005-Year)
DISCUSSION
These two studies use photo-identification of humpback whales migrating along the east coast of Australia and two different methodologies to estimate abundance of this population in 2005. Each study, while using the same techniques – photo-identification capture-recapture, relies on different assumptions and is subject to different bias. Each has strengths and weaknesses.
Previous research showed that the migration has a temporal sequence of different classes of whales. It was, therefore, considered particularly important that the surveys at each site be timed to include the major part of the migration on either side of the peak past that location in order to repeatedly sample from the entire population rather than from a somewhat different subset at each site.
For the multi-point single-year study it was expected that apparent behavioural response would be manifested in the models to the extent that we were unsuccessful in this and that the whales sampled at one site were present in greater or lesser proportion at another. There was some evidence of this in as far as the models displaying a behavioural response structure could not be reliably distinguished from those that did not by the AICc criterion. Nonetheless, the simplest model with equal capture probabilities at Byron Bay and Hervey Bay and no behavioural response had twice the likelihood of any behavioural response model. While this situation may have created a dilemma had these models produced
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markedly different population estimates, the similarity of the estimate from this model and the model-averaged estimate, which included the behavioural response models, is reassuring.
Using land-based counts from North Stradbroke Island for the 2004 season, Noad et al. (2007) calculated an abundance estimate for this population of 7,090±660 (95% CI) and an annual increase of 10.6± 0.5% (95% CI). Extrapolating this figure to 2005 would produce an estimate of 7,842 (95% CI 7,112–8,572). Our estimate for the 2005 season using the multi- point single-year capture-recapture analysis provided a single best estimate of 7,024 (95% CI 5,163–9,685) whales and a model averaged estimate of 7,041 (95% CI 4,075–10,007) whales. Our multi-year single-point capture-recapture analysis estimated the number of humpback whales migrating along the coast in 2005 to be 7,390 (95% CI: 4,040-10,739). While all three of these population estimates (land-based counts, multi-point single-year capture-recapture, and multi-year single-point capture-recapture) rely on different methodologies, assumptions and bias, they all produce a population estimate in the same range (even though the CI may vary considerably between estimates).
5.5.1 Further considerations The combination of a multi-point, multi-year study would enable a more accurate, reliable and informative analysis through the use of a robust design model (e.g. Kendall and Nichols 1995; Kendall et al. 1995, 1997).
The current multi-point analysis only considers humpback whales that undertook migration along the east coast of Australia during 2005. However, Brown et al. (1995) suggested that a percentage of females may not undertake the migration annually. This hypothesis could be tested by undertaking inter-year capture-recapture studies.
Chaloupka et al. (1999) suggest that only a portion of the whales migrating along the east coast of Australia enter Hervey Bay and therefore would not be available for sampling there. This point is further supported by Franklin (2014) who found that the whales utilising Hervey Bay are a sub-population of the EAH population and Schmitt et al. (2014) who determined a genetic sub-structure in the EAH population. Valsecchi et al. (2010) also raises the theory of a mixing of humpback whales from neighbouring populations in the South Pacific: a theory that requires further examination.
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These factors will not bias the abundance analyses of this chapter, assuming that the EAH were available for capture at two or more of the sampling locations (Byron Bay on the northern migration and Ballina during the southern migration). Aerial surveys off the coast of Byron Bay and Ballina would also help to establish the width of the current migration corridor, and determine whether it is possible that some whales are not available for capture at any of the three sites because they migrate further offshore at Byron Bay and Ballina and do not enter Hervey Bay.
While a multi-year, multi-point capture-recapture study would provide a more accurate and robust result, due to the rapid increase in the population (estimated to be in excess of 24,000 individuals in 2015 – pers. comm. Mike Noad, February 2016) it would be extremely difficult and logistically challenging to obtain a sample size large enough at each location within each year to undertake this analysis. A sample size of approximately 10% of the population (approximately 2,400 individual fluke identifications) would be required per year in order to undertake this analysis with the degree of accuracy required. Unless there are unlimited resources available it is not considered viable to undertake such a study. Land- based counts, such as those co-ordinated by Noad et al. (2007) at Point Lookout will provide a more accurate ongoing assessment of the population recovery.
5.6 ACKNOWLEDGEMENTS
The studies at Byron Bay were undertaken with support from New South Wales National Parks and Wildlife Service, Southern Cross University, Southern Cross University Whale Research Centre, University of Newcastle, Cape Byron Headland Reserve Trust and Blue Planet Marine.
The long-term study of humpback whales in Hervey Bay being conducted by Trish and Wally Franklin is supported by The Oceania Project and by an Australian Research Council Linkage grant with the International Fund for Animal Welfare (IFAW).
We thank Greg Luker for providing the maps of the study areas (Figure 5.1 and Figure 5.3), Jeff Laake and John Calambokidis for constructive comments on the draft multi-point single-year capture-recapture manuscript and the many volunteers who assisted with the fieldwork for these studies.
The authors would like to thank all the volunteers who assisted with the research, with special thanks to Adrian Oosterman and Merv Whicker. Our thanks also go to Rochelle Constantine for
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undertaking the quality control assessment of the fluke identification catalogue for the multi- year single-point capture-recapture analysis.
The research undertaken off Ballina and Byron Bay was conducted under Scientific Research Permits issued by the Department of the Environment, Water, Arts and Heritage under the EPBC Act 1999 (permit number E2001/0005) and the New South Wales National Parks and Wildlife Service (permit number S10403). Research undertaken in Hervey Bay was conducted under research permits issued by the Queensland Parks and Wildlife Service (permit numbers MP2006/020 and WISP03749806).
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CHAPTER 6 THREATS AND STATUS OF EAST AUSTRALIAN HUMPBACK WHALES6
6.1 ABSTRACT
Although whaling (commercial or scientific) is no longer considered a significant threat to humpback whales, they remain subject to a variety of other threats. The impact of these upon individual animals or populations is difficult to determine as is their cumulative effect.
The current and predicted increase of human activity along the east coast of Australia increases the potential for interactions to occur with East Australian humpback whales (EAH). The cumulative impacts of multiple stressors must be considered in the overall context of management of this species. A qualitative assessment of threats using a risk matrix identified that the high priority key threats facing EAH are: anthropogenic noise; coastal and offshore developments and operation impacts; climate change and variability; and commercial whaling. A critical review of the current management tools (national and international) indicated that management tools appear to have limited capability to detect and manage the potential impacts.
Using recent scientific knowledge of Australian humpback whales, a preliminary assessment of EAH against the Threatened Species criteria of the EPBC Act demonstrated that it no longer meets any of the criteria for its current listing as ‘Vulnerable’. This is primarily due to the strong recovery of the population and its continuing recovery. Consideration of delisting this population is recommended.
6 This chapter is based on the draft Conservation Management Plan (CMP) for humpback whales in Australian waters that Paton co-authored in 2013 with Simon Childerhouse and Melinda Rekdahl for the Department of Sustainability, Environment, Water, Population and Communities (SEWPAC). Any text of the CMP not originally written by Paton has been completely rewritten by him for this thesis. The assessment of the current status of the EAH population against the Threatened Species criteria under the EPBC Act undertaken in this chapter was not part of the draft CMP submitted to SEWPAC and represents original work by Paton.
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6.2 INTRODUCTION
The east Australian humpback whale (EAH) population is one of three that utilise Australian waters. The two main populations of humpback whales recognised in Australia are those that migrate along the west coast (Breeding Stock D) and those that migrate along the east coast (Breeding Stock E1). These populations are primarily differentiated by having separate and non-overlapping breeding areas although there is a low level of interchange between these populations on their Antarctic feeding areas and a small amount between breeding areas (see Chapter 3). There is also a third distinct population present in Australian waters – those that migrate through the waters of Norfolk Island and appear to be more closely aligned with whales that breed in New Caledonia (Breeding Stock E2) than in east Australia.
This chapter reviews and assesses the conservation status of EAH including a critical evaluation of the threats and current status of this population under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). While this chapter will focus on the EAH population, some management consideration of the other populations within Australian waters is also necessary in order to put the EAH population in a broader context. In addition, a critical evaluation of the current status of the EAH population against the Threatened Species criteria under the EPBC Act is undertaken in order to assess the appropriateness of its existing listing as ‘vulnerable’.
This chapter will:
1) Identify the primary long-term management objective for the recovery of the EAH population;
2) Review current threats to the EAH population including a critical evaluation of risk;
3) Identify existing conservation and management measures in place in order to protect humpback whales with a focus on the EAH population;
4) Review the current status of the EAH population against the EPBC Act criteria and make recommendations for listing or delisting; and
5) Make recommendations for further research to address gaps in the current knowledge for EAH.
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6.3 LONG-TERM MANAGEMENT OBJECTIVE
Southern Hemisphere humpback whales (SHH) were made almost extinct by commercial whaling operations in the 20th century. Following the implementation of a number of national and international management strategies some populations, including east and west Australian, have shown positive signs of recovery. All still remain, however, at less than their estimated pre-exploitation population size. The rate of recovery across SHH populations has not been consistent. Some populations are recovering very slowly (for example, the Oceania population, Childerhouse et al. 2008) while others show no signs of recovery (for example Fiji, Paton and Clapham 2002; Gibbs et al. 2006).
Before undertaking a review and assessment of the conservation status of EAH, it is important to determine the primary long-term management objective. The following management objective has been developed in order to guide this chapter and to provide a focus for reviewing the threats and long-term management of this population of whales. This objective has been developed from, and is consistent with, the requirements under the EPBC Act for threatened species and other national and international legislation and agreements to which Australia is signatory.
The primary long-term management objective for Australian humpback whales is:
Humpback whales within Australian waters recover to their pre‐exploitation levels of distribution and abundance, and they can be removed from the Threatened Species list under the EPBC Act.
6.4 THREATS
Potential and existing threats to EAH are reviewed in order to provide an understanding of their nature and to assess their level of impact. The identified threats are those that have previously been identified and potential threats are those that may impact individuals and/or a population in the future. It is important to understand threats to this population so that management responses can be evaluated and recommendations made about gaps or duplication.
6.4.1 Entanglement Humpback whales migrate bi-annually through coastal inshore waters. This exposes them to a range of impacts associated with increased coastal development, aquaculture and fishing
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activities, including entanglement. Reports of entanglements have increased in recent years. The level of reporting of these impacts will, however, be an underestimate of the actual severity of this issue as many entanglements are unreported (Robbins et al. 2009). Data from the USA indicate that fewer than 10% of humpback whale entanglements are reported (Robbins et al. 2009).
Entanglements occur when a whale becomes caught in a range of equipment including:
Float ropes from crab/lobster pots and other lines extending to the surface; Shark nets and drum lines (see Figure 6.1); Gill and drift nets; Aquaculture equipment including: Pearl oyster farms; Mussel farms; Fish farms; and Discarded or lost fishing gear – ghost nets or other marine debris.
Figure 6.1: Humpback whale entangled in a shark net. Source: Trevor Long, SeaWorld.
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Depending on the severity of the entanglement, a whale may be able to break free of the entanglement, however, entanglements can cause serious injury and/or distress to a whale even if they are only short term in nature. Potential impacts of entanglements on humpback whales include:
Short-term impacts: Minor inconvenience; Behavioural change; and Minor injuries; Long-term impacts: Chronic injuries and potential for infection; Disruption to migration; Reduced mobility, which may affect ability to migrate, feed, breed or care for offspring; Increased potential for predation; and Death of an animal or death of a female’s calf.
Paton (2005) collated entanglement data for the east coast of mainland Australia (Queensland to Victoria). These data were based on reports from each State Government’s annual submission to the Commonwealth Government’s annual scientific progress report to the IWC on cetacean-related activities within Australian waters. In addition, the Queensland Department of Environment’s stranding and entanglement database and NSW Department of Primary Industry records were reviewed for the same period. Anecdotal records from a range of reliable sources (including whale research organisations) for the same period were also sought. This information was compiled for inclusion in presentations at National Disentanglement Training workshops, which Paton coordinated in 2004 and 2005 (Paton 2005).
In Western Australia (WA), there were a total of 33 whale entanglements reported between 1990 and 2004 (Cochran pers. comm. 2004). For the period 1997 to 2004, however, 42 entanglements were reported on the east coast of Australia (Paton 2005; Figure 6.2). Over this period the rate of population increase for humpback whales on the east coast of Australia was approximately 11% per annum. This increase in whale numbers may affect the probability of entanglements. The rate of entanglement for the WA coast is likely to be an underestimate based on a number of factors including:
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The WA humpback whale population is substantially larger than the EAH population, therefore the probability of entanglements occurring would be expected to be higher; A large rock lobster fishery operating on the WA coast, therefore a significantly increased number of obstacles in the water, which when combined with the larger humpback whale population would also increase the probability of entanglements occurring on this coast; and The remote nature of much of the WA coast resulting in a large number of unreported entanglements (C. Bass pers. comm. September 2013).
18 16 14 12 10 8 6
Number Number incidents of 4 2 0 1997 1998 1999 2000 2001 2002 2003 2004 Year
Figure 6.2 Number of reported humpback whale entanglements per year for eastern Australia: 1997-2004 (n=42). Source: Paton, 2005.
The increase in reporting of entanglements in Australian waters coincides with the increasing humpback whale population following the cessation of commercial whaling. It is also most likely the result of better State and Commonwealth reporting systems and networks, and a concurrent increase in the number of coastal developments, and aquaculture and fisheries activities, which probably lead to increased interactions between whales and gear.
As an entanglement usually has an impact on an individual whale, the potential impact at a population level will be minor assuming entanglement rates are low. Nonetheless, as humpback whale populations, coastal development and fisheries activities continue to
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increase around Australia, there will be potential for an increase in entanglement rates that, if not managed effectively, could eventually impact at a population level. In order to address the rising concern about entanglements, an Australian Large Whale Disentanglement Network has been developed through collaboration of skilled personnel and government agencies to free large whales from entanglements.
Shark Control Entanglements in shark nets and drum lines are a concern off the coast of Qld, NSW and WA as shark control programs are in place along many popular swimming beaches. Shark control equipment accounted for 49% of humpback whale entanglements recorded between 1997 and 2004 on the east coast of Australia with the bulk of these entanglements occurring in southeast Qld (Figure 6.3). The highest number of all entanglements (36%) are reported in September, which coincides with the peak of the southern migration of humpback whales on the Qld east coast (Figure 6.4). The cohorts that are most represented in entanglements in shark control equipment are sub adults and mothers with calves (Paton 2005). There is evidence that pods containing humpback whale mothers and calves travel closer to the coast than other cohorts (Brown 2009). As shark control equipment is set in the inshore waters, this may explain the higher incidence of entanglements involving this pod composition.
A range of mitigation measures to reduce the incidence of whale entanglement in shark nets and fishing gear have been tested. In Qld, acoustic pingers specifically designed as a mitigation measure for humpback whales, are attached to shark nets during the migration season. While this research suggests that the types of pingers used should be adequate to deter whales from approaching the nets (Erbe and McPherson 2012), long term monitoring and behavioural studies are required in order to determine their effectiveness.
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60%
50%
40%
30%
20%
Percentage of of Percentage incidents 10%
0% Shark control Crab/lobster gear Other fishing gear Unknown
Source of entanglement
Figure 6.3: Percentage of entanglements for eastern Australia by source of entanglement: 1997-2004 (n=37). Source: Paton 2005.
40%
35%
30%
25%
20%
15%
Percentage of of Percentage incidents 10%
5%
0% Jan Feb March April May Jun July Aug Sept Oct Nov Dec Months
Figure 6.4: Percentage of entanglements by month - eastern Australia: 1997- 2004 (n=33). Source: Paton 2005.
Commercial fisheries and aquaculture equipment Commercial fisheries and aquaculture equipment (excluding shark control) accounted for 37% of the recorded humpback whale entanglements between 1997 and 2004 on the east coast of Australia (Paton 2005). The number of aquaculture farming sites has increased around Australia. These, along with other commercial fisheries using nets, cages and lines,
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provide opportunities for entanglement. The Australian Government is working closely with commercial fishing industries to ensure that all equipment used limits the risk of entanglement of whales and dolphins. In order to address this issue the Western Australian Rock Lobster Council, working in conjunction with State and Commonwealth agencies, has implemented a Code of Practice (the Code) to minimise entanglements of whales in rock lobster pot lines. The Code has the potential to minimise the incident of entanglements, however, personal observations by the author have indicated that the extent of adoption of the Code varies between regions and fishers. Observations by the author off the WA coast in 2013 (for example Dongara, 29°S 115°E; and Geraldton 28°S 115°E), indicated that when pots were moved into shallow water, the surface lines were not always shortened. This sometimes resulted in extensive amounts of slack line floating on the surface, which has the potential to entangle a whale. This practice is inconsistent with the Code. The effectiveness of the Code is unknown and further monitoring is required in order to determine this.
Marine Debris Marine debris is defined as any persistent, manufactured or processed solid material discarded, disposed of or abandoned in the marine and coastal environment (UNEP 2009). Marine debris can include, but is not limited to, non-biodegradable floating materials lost or disposed of at sea, derelict fishing gear, plastic garbage such as bags, bottles, ropes, and so on. The EPBC Act lists the interaction between marine debris and marine species as a key threatening process and the potential impacts for cetaceans are through entanglement or ingestion. As identified previously, the number of entanglements of humpback whales in Australia has increased in recent years. While the bulk of these are not attributable to marine debris, there have been reports of polyfilament and monofilament fishing gear scarring on individuals (WWF 2010). Ceccarelli (2009) reported that since 1998, plastic debris was the source of impact in at least 104 events (entanglement or ingestion) involving cetaceans in Australia. Most of these events were through entanglement. The potential for humpback whales to ingest marine debris is relatively low as they rarely feed while migrating or in the breeding areas where there is the greatest concentration of marine debris. The ingestion of marine debris is still a possibility, however, as debris is generally highly mobile and can occur in both coastal and pelagic habitats.
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6.4.2 Vessel disturbance and strike
Ship strike Collision with ships is one of the main causes of anthropogenic mortality to baleen whales worldwide (Vanderlaan and Taggart 2007). Humpback whales are one of the most frequently reported victims of ship strikes worldwide (Peel et al. 2015), however, there has been little focus on vessel strikes on whales in Australian waters. Quantifying any population level impacts of ship strike is very difficult as collisions are frequently unnoticed and consequently go unreported (Laist et al. 2001; Vanderlaan and Taggart 2007).
There has been a significant increase in the number of commercial, industrial and recreational vessels in coastal waters of Australia associated with the substantial increase in coastal and port development in recent years on both the east and west coasts of Australia (Silber and Bettridge 2012). There has also been a significant increase in the amount of shipping through the Great Barrier Reef (GBR) Region over the last ten years and economic forecasts indicate that there will be a further significant increase (that is, a 3.5-fold increase by 2020) in shipping levels over the next 10 to 15 years (GBRMPA 2013).
Recent work by Smith et al. (2012) has shown that the waters of the GBR lagoon off central Qld is a potentially important wintering area for humpback whales during the breeding season. This area is also the location of a major junction of the inner north-south and east- west shipping routes within the GBR. With the ongoing increase in humpback whale numbers and a projected increase in shipping activity within these breeding grounds, there is potential for an increase in the incident of ship strike for this population.
A national strategy to prevent vessel strikes on whales is currently being developed by the Commonwealth Government. This strategy includes the development of a national ship strike database managed by the Australian Marine Mammal Centre. Under the EPBC Act as well as State and Territory legislation, all collisions with cetaceans within Australian waters must be reported. However, personal observations by Paton of the number of whales exhibiting evidence of ship strike (such as propeller scars and wounds consistent with ship strike (Figure 6.5 and Figure 6.6) in comparison with the number of reports received by the relevant Government agencies, would indicate that a high percentage of incidents are unreported.
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Figure 6.5: Humpback whale showing evidence of propeller marks. Source: R. Butt.
Figure 6.6: Humpback whale showing evidence of ship strike. Source: D. Paton.
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Whale watching The continued growth of the whale watching industry worldwide has also been seen in Australia with a reported increase of participants from 735,000 in 1998 to 1,635,372 in 2008 (SEWPAC 2011). The Australian whale watching industry is generally focused on the seasonal presence (between June and November) of humpback whales on the east and west coast of Australia. Although each State has adopted the Australian National Guidelines for Whale and Dolphin Watching 2005 (Australian Government 2008b), there is a considerable variation in the range of management arrangements and considerations between each State jurisdiction. For example, commercial whale watching in some States can only occur in Marine Parks or designated areas, while in others it can occur in any area providing the operators obtain a permit. Other States only regulate whale watching activities if they occur within a Marine Park, whereas outside of Marine Parks, whale watching is unregulated.
While there is evidence to demonstrate that whale watching has conservation benefits through education and raising awareness from observation of animals in their natural habitat, there is increasing concern about the number of whale watch operators in some areas (for example on the NSW coast). Of main concern are direct impacts on whales resulting from harassment and disturbance in critical habitats (particularly breeding or resting areas). There are also concerns associated with the potential pressure on vessel masters from unreasonable public expectations regarding acceptable approach limits to whales. Studies have demonstrated that whales can exhibit a number of behavioural responses in the presence of whale watching vessels including longer dive times and avoidance response (Bejder et al. 2006; Stamation et al. 2007; Schaffar et al. 2009). In May 2013 the IWC held a meeting in Brisbane, Qld, to review their five-year strategic plan to support the development of a sustainable and responsible whale watching industry. The plan was developed in order to address growing concern about the potential impacts from this industry.
Increased shipping activities Disturbance and displacement of humpback whales from key habitats is also a potential impact especially given the significant increase in the numbers of commercial, industrial and recreations vessels in coastal waters. Disturbance occurs when a whale modifies its behaviour in response to the noise and/or presence of a vessel. Persistent interruptions of important behaviours such as feeding, resting, courtship and mating can be energetically costly and affect the reproductive success of individuals. When compounded, the potential impacts of disturbance from vessels and the direct risk of boat strike may outweigh the
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benefits of whales using an area, and may result in the displacement of individuals or populations.
Displacement may not necessarily be a significant impact if there are enough resources elsewhere to which whales can move and exploit. Conversely, if the resource is spatially restricted or limited, then the impacts of displacement can be significant. If whales can move to alternative suitable habitat they may be less affected than animals forced to remain and tolerate the effects of disturbance (Gill et al. 2001). Both the reduction of habitat availability and the cost of disturbance can affect the survival of individual whales and, if of sufficient magnitude, entire populations.
6.4.3 Anthropogenic noise The impacts of anthropogenic noise sources on marine mammals is an area that has been attracting an increasing amount of attention in recent years and is of growing concern. There are a wide range of anthropogenic noise sources that have the potential to impact on cetaceans. These include: seismic exploration, shipping noise, military sonar systems, noise associated with coastal developments (such as dredging, blasting and pile driving) and acoustic deterrent devices. A wide range of behavioural changes may occur in response to anthropogenic noise, including:
Changes in dive time/dive profile; Changes in respiration rate; Changes in direction of travel (for example, migration); Disorientation (including the potential for strandings); Reduction in foraging; Reduction or stopping of calling/communicating; and Displacement.
Additional impacts include masking of calls, communications, echolocation or other important natural sounds, temporary or permanent effects on hearing or other organs (physical trauma) and effects on prey species such as krill (Nowacek et al. 2007; Southall et al. 2007). A number of factors may influence the extent to which a behaviour is impacted. These include species, age, gender, health, behavioural state, prior exposure (habituation), and/or distance from the source (Nowacek et al. 2007). The breeding success for impacted individuals may also be reduced and ultimately affect the population (Wright et al. 2007).
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Determining biologically significant impacts on individual animals or at a population level is very difficult and requires long-term data and targeted research projects. In the absence of documented data to evidence impacts of anthropogenic noise on cetaceans, many management agencies apply the precautionary principle (for example DOC 2013).
Any noise loud enough has the potential to shift hearing thresholds but the extent to which this occurs depends on the nature of the noise and the species in question (Richardson et al. 1995). Impacts on hearing can either be temporary (Temporary Threshold Shifts - TTS) or permanent (Permanent Threshold Shift – PTS). TTS and PTS have been documented to have adverse effects on marine mammals (Southall et al. 2007). The long-term effects of noise exposure are poorly understood, with limited knowledge about the hearing range and the sensitivity of marine mammals. However, humpback whales are considered to be susceptible to TTS given their suspected low frequency hearing sensitivity and the low frequency nature of many of the potential noise sources (Popper and Hawkins 2012).
Australia has had an unprecedented increase in the level of coastal development and shipping activity, particularly due to increasing resource exports and new port developments. These activities will increase anthropogenic noise levels in the marine environment and may have adverse effects on the seasonal usage patterns of humpback whales within Australian waters.
Southall et al. (2007) undertook a major review of the impacts of noise on marine mammals and developed recommendations on marine mammal noise exposure criteria based on behavioural disruption, TTS and PTS. Their work set the benchmark for marine mammal noise exposure assessment. Southall et al. (2007) also found that there were no or limited responses by low-frequency cetaceans (including humpback whales) to continuous (non- pulsed) received sound levels up to 120 dB re 1 µPa but there was an increasing probability of avoidance (and other induced behaviours) in the 120 to 160 dB re 1 µPa range. To provide some context, ambient noise in the ocean, which will vary with sea conditions and other biological noise (such as snapping shrimp, fish chorus and marine mammal calls) can vary from 60 for a calm day to over 100 dB re 1 µPa during storm events (Richardson et al. 1995). A high speed outboard driven vessel typically is in the order of 175 1 µPa-m and ships in the order of 170 to 180 1 µPa (Richardson et al. 1995).
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Seismic surveys The petroleum exploration industry uses high-energy air pressure explosions that are vented underwater at set intervals (such as every 10 seconds) to generate seismic (sound) waves in order to look for petroleum reserves. Typically these sound waves are short, intense, broadband pulses at predominately low frequencies, between 10-300 Hertz (Hz) frequency range and up to 260 dB re 1 µPa @ 1m (Hildebrand 2009). While the bulk of the energy from the sound pressure wave is directed downwards towards the sea floor, there is spherical spreading of the sound pressure wave in all directions. Sound pulses from these surveys are often detectable in the water at some level tens or even hundreds of kilometres from the source especially when sound waves become entrapped within the SOFAR Channel (Hildebrand 2009).
The potential effects of seismic surveys on cetaceans have received considerable attention recently. Many countries now have detailed seismic impact mitigation requirements to minimise the potential impacts of seismic surveys on whales. These focus mainly on whales, and most use ~198 dB re 1 μPa @ 1m as the level at which injury can occur for a single impulse (that is, TTS: Hildebrand 2009). In addition, low frequency noise may mask humpback whale vocalisations, which range between 30-8000 Hz (Payne and Payne 1985; Southall et al. 2007; Hildebrand 2009). A major scientific research project in Australia is currently assessing the behavioural response of humpback whales to seismic surveys (www.brahss.org.au). The results of this project will facilitate the review of Australian seismic guidelines by providing targeted scientific data that can aid development of best practice impact mitigation procedures. Where possible, mitigation procedures based on empirical data will replace those based on a precautionary approach. Presently this is the approach for mitigation procedures in most guidelines worldwide.
Chronic and acute industry noise (including dredging, pile driving, blasting, seabed mining) In recent years there has been a significant increase in the number of coastal developments throughout Australia, mainly associated with the increased demand for resources and petroleum products (Salgado Kent et al. 2009; WADSD 2010). A large number of these projects involve major port developments which require dredging, pile driving and blasting. In addition, there is also growing interest in seabed mining with new technologies being developed to extract a range of resources. Many of these projects result in long-term construction periods lasting over 4 to 5 years.
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Richardson et al. (1995) report on opportunistic observations and a controlled exposure experiment involving dredging impacts on whales. They observed variability in the reactions of individual whales (bowhead whales) to dredging activity. This may reflect variation in individual sensitivities to noise sources but there is potential for habituation to ongoing dredge noise even if whales are initially disturbed by it. Furthermore, individual variation in response in this study may be related to variability in the acoustic characteristics (propagation) of the environment, with individuals receiving differing levels of noise.
Unlike noise from dredging, pile driving (hammering) is a pulse noise source. Hammering occurs as frequently as every few seconds, and noise increases with pile size, ground hardness and hammer energy. Richardson et al. (1995) reports the strongest components of the sound output from piling is in the 30-200 Hz range, and at 1 km from the source were 25 to 35 dB above the ambient sound level with a signal duration of approximately 0.2 seconds. Depending on propagation in the area, this level of sound output could be heard underwater for tens of kilometres from the source.
Explosives are used in a wide range of applications during construction activities as well as decommissioning of offshore structures. Explosions are generally broadband in frequency (including low frequency energy) and the sound pressure level of charges can be up to 304 dB re 1µPa @ 1m (Hildebrand 2009). At these amplitudes, there is potential to cause serious damage to marine mammals depending on proximity to the source (Southall et al. 2007).
Shipping noise Australian coastal waters have seen a significant increase in vessel activity. There is potential for this to increase further, particularly within the breeding grounds for the EAH population (section 6.4.2). Noise from vessel traffic, in particular from large commercial ships, has been identified as an area of concern as it has the potential to mask marine mammal communication, disturb natural behaviour and increase stress levels (Rolland et al. 2012; Hatch et al. 2008; Melcon et al. 2012).
Larger ships tend to produce lower frequency and louder sound with the peak energy output below 150 Hz and amplitudes above 205 dB re 1µPa at 1m, whereas smaller vessels produce higher frequencies generally up to 5 kHz and source levels around 170-180 dB re 1µPa at 1m. In addition to size affecting noise output, vessel speed can also impact on the noise generated by a ship, with faster vessels producing higher source levels (Hildebrand 2009).
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The predicted increase in shipping within Australian waters along with the lack of temporal and spatial regulations reducing shipping traffic in key areas creates potential for shipping noise to have serious implications for humpback whales. This includes the masking of humpback whale communications, disturbance of natural behaviour and increase of stress levels. This would be most important in the breeding grounds.
Scientific and military sonar systems Like seismic surveys, the potential for the impact of sonar on whales has attracted a great deal of attention in recent years. Military sonar has been implicated as the potential cause of a number of stranding events involving odontocetes, particularly beaked whales (Cox et al. 2006).
Sonar has a wide range of applications from commercial sonars used to detect underwater targets such as the seabed, fish and plankton through to low frequency (LF) active sonar, which has military application to scan large distances and detect submarines. LF has a frequency range of 100-500 Hz and source levels of approximately 215 dB re 1µPa at 1m per unit (Hildebrand 2009). In addition to LF, the Australian military also uses mid- frequency sonars (1-10 kHz). These usually have much higher source levels (>235 dB re 1µPa at 1m) and are used to detect submarines at close ranges (Hildebrand 2009). High frequency (HF) active sonar operates between approximately 30-500 kHz. The Royal Australian Navy (RAN) used HF systems for mine hunting, sea floor searches, and hydrographic surveys. This frequency range is similar to that used by commercial sonars and fish finders. The RAN manages the use of sonar through defence environmental assessment procedures, which are developed in consultation with the Australian Federal Government Department of the Environment.
Mid Frequency (MF) and HF sonar generally emit sounds above the vocalisation frequency range of most baleen whales. However, MF sonars are still in the range of some humpback whale vocalisations, which can reach up to 8 kHz (Payne and Payne 1985). These sonars generally emit sounds at lower source levels than the military sonars but still have the potential to have a negative impact on marine mammals if they are used in close proximity. A number of researchers have shown that even though baleen whales produce vocalisations well below the frequency range of MF they still display behavioural disturbance in response to their use (Melcon et al. 2012).
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LF sonar has been shown to have a significant impact on humpback whale song duration. A sound source produced by an Ocean Acoustic Waveguide Remote Sensing Experiment in the Stellwagen Bank National Marine Sanctuary reduced the production of humpback whale song for the duration of the experiment (Miller et al. 2000). A recent study undertaken off Florida found that minke whale vocalisation events were either completely absent or greatly reduced during a military exercise in the area (Dominello et al. 2013). The use of sonar (in particular LF and the systems using the lower frequencies of MF band) within Australian waters has the potential to pose a threat to the normal behaviour of humpback whales, however the severity of the impacts at both an individual or population level is poorly understood. While there may be some instances overseas in recent years where marine mammal strandings have occurred in the same area and at the same time as naval operations, there is no evidence to support that stranding events in Australian waters are associated with any anthropogenic sound sources.
Acoustic deterrent devices To reduce the potential of entanglement in human made structures (particularly shark nets and aquaculture equipment) acoustic deterrent devices or pingers have be used within Australian waters (Erbe and McPherson 2012). These devices are used on fishing and aquaculture equipment and usually emit pulses of sound (e.g. generally <180 dB re 1µPa at 1m for transient structures and >180 dB 1µPa at 1m for permanent structures) within the hearing range of target species (Erbe and McPherson 2012). Systems designed for minimising humpback whale entanglement in shark nets emitted tones at 3 to 10 kHz at source levels of 135 dB 1µPa at 1m and were predicted to be audible up to 100 m from the source (Erbe and McPherson 2012). However, there are mixed reports as to the effectiveness of these devices on different species with potential for habituation and/or animals identifying the sound source with potential food source associated with some fishing operations (the “dinner bell” effect). Therefore long-term monitoring and behavioural studies are required in order to determine their long term effectiveness (Franse 2005).
Aircraft noise Studies carried out by the Defence Science Technology Organisation (DSTO) has demonstrated that aircraft-generated noise has minimal potential to impact on marine mammals in comparison to other anthropogenic noise sources (Zhang et al. 2004). DSTO developed computer models for a range of aircraft including jet fighters, helicopters and
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military transport aircraft flying at less than 300 m (the current legal height over whales for fix winged aircraft, helicopters is 400 m) in both shallow and deep ocean conditions with varying seabed substrates. Sound generated from the aircraft was determined to be localised and transmitted in a narrow cone into the water column below the aircraft. Unless the aircraft was hovering above a whale (such as a helicopter-based whale watch operation), the localised nature of the sound as well as the speed at which the aircraft moves past the whale indicated that there would be very little potential for exposure to marine mammals from normal aircraft operations.
6.4.4 Habitat degradation and modification As humpback whales are a coastal species, they are susceptible to impacts from habitat degradation and modification of coastal regions. Habitat degradation, modification and fragmentation has the potential to result in reduced occupancy or displacement, compromise breeding success and may result in mortality of some individuals. The level of impact from habitat degradation or modification will be dependent on the significance of the area for key biological activities for humpback whales. Developments in a location where key processes are undertaken such as breeding, calving and feeding are likely to have a greater impact than other locations within the migratory corridor. Additionally the cumulative impacts of widespread (even low level) habitat modification could have wide reaching implications for the health and growth of a population. Given that both the migratory population of humpback whales on the east and west coasts of Australia are increasing at or close to the maximum biological rate, this impact does not appear to be a limiting factor for EAH at the present time. However, ongoing monitoring and management are required in order to ensure these considerations do not become a significant limiting factor in the ongoing recovery of EAH.
The installation of offshore infrastructure and coastal development has the potential to degrade important habitat utilised by a range of coastal migratory marine mammal species. Coastal developments may include: dredging, blasting, and pile driving during processes for facilities such as ports, break walls, marinas and aquaculture infrastructure. All of these developments have the potential to alter local currents and may impact in the short term through sedimentation or pollution during construction and in the long term though degradation of habitat suitability or availability.
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Competition from other recovering baleen whale species populations There is potential for humpback whales to be in competition with other populations of whale species that are recovering from whaling activity. At present, however, all other major baleen whale species that may constitute competition are either still highly depleted with limited signs of recovery (for example, blue whales and sei whales) or feed in different locations (such as, fin whales and minke whales).
6.4.5 Whaling
Commercial Whaling The decline of Australian humpback whale populations as a result of commercial whaling was well documented by Dawbin (1997) and Chittleborough (1965). However, the cause of the rapid decline in whale numbers was not confirmed until the late 1990s when the true records of the illegal Soviet whaling activities in the feeding areas south of Australian waters were reported for the first time (Mikhalev 2000; Mikhalev et al. 2009; Ivashchenko et al. 2011). Currently the IWC has imposed a moratorium on commercial whaling. There is potential for commercial whaling to resume, however, any changes to the current moratorium would require IWC members to vote with a three quarter majority in favour. Although many humpback whale populations are showing strong signs of recovery, including western and eastern Australia, the existing membership of the IWC and the current political climate indicate it would be unlikely that a motion of this nature would gain the necessary support through the IWC.
Scientific Whaling Under Article VIII of the International Convention for the Regulation of Whaling of the IWC, a member country can unilaterally issue itself a permit to kill and process whales for scientific research purposes. Since 1986 Iceland and Japan have used this article and issued scientific research permits on a number of whale species. These permits must include specified quota and catches must be reported annually to the IWC. While Japan has a quota that includes an annual catch of 50 humpback whales in the Southern Ocean (under the JARPA II programme), to date they have not exercised this self-issued authority. Such a hunt may include animals that are part of the EAH population.
In 2010 the Australian Government lodged an objection to the validity of Japan’s scientific whaling program before the International Court of Justice (ICJ). The case was heard in 2013
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and in 2014 the ICJ ruled that whaling by Japan in the Southern Ocean/Antarctic had not been undertaken for purposes of scientific research (ICJ 2014). It was, therefore, considered illegal and so Japan was asked to revoke all existing permits for scientific whaling included in the JARPA II programme and refrain from granting any further permit (ICJ 2014). Japan suspended JARPA II whaling operations in the Antarctic for the 2014-2015 season but in December 2015 Japan’s whaling boats returned to the Southern Ocean in order to catch up to 333 Antarctic minke whales annually under their newly designed whaling programme called NEWREP-A (Government of Japan 2014). NEWREP-A does not include lethal sampling of humpback whales though it does propose to investigate non-lethal research methods such as photo-identification and biopsy sampling on humpback and fin whales, “which could potentially complement or replace lethal techniques used in the context of achieving the research objectives [of NEWREP-A]” (Government of Japan 2014). Japan may alter its NEWREP-A programme to include the lethal sampling of humpback whales in future.
6.4.6 Pollution Marine pollution can be discarded debris of terrestrial or marine origin, including fishing and aquaculture equipment. It can also be changes to water quality through chemical pollution, increased nutrient loads and sediments, or acoustic pollution (section 6.4.3). Pollutants may impact marine mammals directly, such as by entanglement in fishing gear, or indirectly via bioaccumulation and biomagnification from ingesting affected prey. As marine mammals are long-lived and typically at a high trophic level, bioaccumulation of toxins is of concern.
The potential effects of chemical pollutants on marine mammals at an individual or population level is poorly understood. However, with increasing levels of herbicides, pesticides, heavy metals and nutrients entering Australian catchments from run-off, industrial and sewage discharge, this issue is of growing concern. In recent years there has been a focus on Persistent Organic Pollutants (POPs) as they are lipophilic compounds (that is, a compound that can dissolve in fats, oils, and lipids) that enter the marine environment but do not degenerate and therefore have a tendency to accumulate in the food chain. Since POPs are highly mobile and can be transported via the atmosphere and ocean currents they are common in the Southern Ocean where they accumulate in primary producers. Recent research undertaken on the east coast population of humpback whales by Waugh et al.
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(2012) confirmed that there is potential for POPs to have negative impacts with increasing levels detected in stranded animals.
Organochlorine contamination has also been found to have negative impacts through immunosuppression and can lead to a greater susceptibility to infections for a number of marine mammal species (Lahvis et al. 1995; Kannan et al. 2007; Sormo et al. 2009). In Australian waters, organochlorine and heavy metal loads (including mercury) in marine mammals were found to be consistent with those associated with health impacts in marine mammals in other locations (Martineau et al. 1994; Lahvis et al. 1995). While the impact of pollutants on marine mammals is still poorly understood, the work by Waugh et al. (2012) on Australian humpback whale populations highlights the potential for POPs to have a greater impact on health during times of stress. This may lead, therefore, to increased impacts if cumulative environmental stressors affect EAH.
6.4.7 Over exploitation of prey The primary food source for humpback whales in the southern hemisphere is krill (mainly Euphausia superba). This species is also the target of the Antarctic krill fishery. The Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) is the international management agency tasked with the management of Antarctic krill stocks. In the Southern Ocean at present, krill are mainly fished in the South West Atlantic region. There is no current krill fishery off the East Antarctic in the Australian Antarctic Territory, however, there is potential for resumption of krill fishing there. CCAMLR have set precautionary catch limits for krill, but localised excessive fishing still has the potential to impact on species that rely on krill, including humpback whales. In addition humpback whales face the cumulative impact of krill fishing and climate change, which could both impact negatively on their primary food source.
EAH generally feed in the Antarctic but they have been recorded feeding off south-eastern NSW between Jervis Bay and Eden, during the southern migration (Stammation et al. 2007). Feeding in this region is seen annually with the prey reported to be schools of small pelagic fish as well as a coastal krill species (Nyctiphanes australis) (Stammation et al. 2007). In addition to feeding off Eden, there are a number of records of humpback whales feeding off the east coast of Tasmania (R. Gales pers. comm.). The importance of this region as a feeding site for EAH is not known, but it may be opportunistic in nature as animals migrate south to
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the traditional feeding grounds in the Antarctic. Local prey depletion around Australia may therefore also be an issue for EAH.
6.4.8 Disease In recent years there has been evidence of increasing levels of disease and skin lesions in humpback whales (Castro et al. 2011), however, it is very difficult to determine if the cause of the diseases are anthropogenic or natural. While there is no documented evidence of large scale mortality events in humpback whales as a result of disease, there are cases from other marine mammal species such as over 18,000 harbour porpoises dying from a morbillivirus infection in 1987-88 (Van Bressem et al. 1999).
Two mortality events linked to toxic dinoflagellates were documented for humpback whales in the Atlantic (Van Bressem et al. 1999). In 2009, on the west coast of Australia, 49 humpback whales were found dead or stranded. This figure is ten times the annual average for this population (Holyoake et al. 2011). It was speculated that the cause of these mortalities was either disease or anthropogenic impacts, or a combination of both (Holyoake et al. 2011). In addition, this population may be approaching carrying capacity (K) and such events may reflect a natural increase in mortality as a result of non-human related causes (that is, density dependence). It is very difficult to tease apart what triggers an increase of disease in a population, however anthropogenic causes may increase stress levels resulting in a population being more susceptible to an outbreak of disease.
6.4.9 Increased mortality as a result of reaching carrying capacity
While this is not technically a threat, if EAH population reaches K, then an increased mortality rate within the population may result due to density dependent factors. The east and western Australian humpback whale population growth rates are among the highest recorded for any humpback whale population in the world and are close to or exceed the theoretical reproductive limit of the species (Best 1993; Brandao et al. 1999; Bannister and Hedley 2001; Zerbini et al. 2010). This rapid growth rate cannot continue indefinitely and the population growth will eventually slow or potentially even decline if the population overshoots K. An example of a baleen whale population that overshot K is the North Pacific gray whale. This population, like humpback whales, was depleted by over exploitation and has been recovering over the last 50 years. Punt and Wade (2010) documented the recovery of this population and reported it reached (or overshot) K in approximately 1999. This
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resulted in increased mortality and a drop in whale numbers in 2000 by approximately 29% (Punt and Wade 2010).
As there have been significant environmental and anthropogenic changes since humpback whale populations were at pre-exploitation K, the historical K for these populations may have now changed. The EAH population, like that of the North Pacific gray whale, is one of the few large whale populations where the recovery from the edge of extinction has been well documented. This population is potentially approaching K and represents a good test case on how baleen whale population dynamics change as they reach K.
Density dependent population demographics can also impact on life history and survivorship parameters. A population that is well below K will potentially not have to compete for resources and therefore may have a greater reproductive success rate. The east and western Australian populations have potentially been recovering with limited competition for resources, which may have led to their high recorded recovery rates.
Braithwaite et al. (2012) recently investigated the effects of K on the use of space in the resting grounds of the west Australian humpback whale population. The study found that whale pods do maintain a distance from each other in the resting grounds. While Braithwaite et al. (2012) found that whales would appear to choose to maintain a distance from other pods, it does not mean that this is the minimum distance they will tolerate. However, this factor may determine the number of animals that can occupy an aggregation area where suitable habitat is limited. This issue has important implications for the management and protection of key habitats for humpback whales, particularly given the increasing competition with other anthropogenic activities within the breeding grounds.
While technically not a threat, reaching K is likely to be a source of additional mortality and something that may soon affect the EAH population. An increase in the number of dead humpback whales observed may not be the result of a threat, rather simply the outcome of a successful recovery.
6.4.10 Climate variability and change While there has been increasing attention given to the effects on marine ecosystems of anthropogenic-driven climate change (Doney et al. 2012), it is very difficult to determine the potential impacts of climate change on a given species. This is largely due to uncertainties about the nature and magnitude of changes in any given area. Climate change
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has the potential to result in ocean acidification and changes in salinity, changes to ocean circulations, decreasing sea ice cover, changes to sea surface temperatures, and rising sea levels (Learmonth et al. 2006). As most species have specific environmental requirements, even small changes to the marine environment can have potentially serious implications for species survival. While there is potential for direct impacts on species abundance, migration timing and range, species distribution, changes to prey/predator relationships, prey availability and reproductive timing and success, there is also potential for cumulative effects such as increased disease transmission and host susceptibility. All of these issues have the potential to impact on the health and survivorship of a species (Laist et al. 2001; IPPC 2007; IWC 2011).
Research has shown that a decrease in the pH of sea water (from ocean acidification due to increased absorption of carbon dioxide from higher levels in the atmosphere) can be detrimental to Antarctic krill production (Kawaguchi et al. 2011). Further research is already showing that a number of species, including baleen whales, are showing signs of impact as a result of climate change (Nicol et al. 2008). Nicol et al. (2008) suggest that the distribution of humpback whales on feeding grounds may be influenced by large-scale oceanographic processes, such as sea ice extent, and the abundance and distribution of secondary producers like krill.
Humpback whales are migratory and although well adapted to changing environments, they are still heavily dependent on the timing of key ecosystem features while on migration or at their destination. Therefore, a change in ice melt, sea surface temperature or ocean currents could alter food availability and delay or alter migratory timing. Changes to migration timing may have important implications for the time spent in key habitats and for migratory species.
6.4.11 Cumulative impacts The cumulative impacts of multiple stressors on EAH may have long term implications. The direct and indirect threats outlined above have the potential to significantly impact on Australian humpback whale populations. This is even more evident when considering the uncertainty of the severity of any impacts. The impacts of climate change are likely to exacerbate existing threats such as habitat loss, pollution and noise disturbance by reducing the adaptive capacity and resilience of individuals and populations to cope with change. The potential for cumulative impacts, especially with the increased level of coastal development,
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shipping and other anthropogenic impacts must be considered in the overall context of management of this species.
6.5 THREAT PRIORITISATION
6.5.1 Prioritisation process Each of the threats outlined in the previous section has been assessed using a risk matrix in order to determine their potential impact on the EAH population. This in turn provides guidance for prioritisation of management actions. The risk matrix follows standard risk assessment criteria considering the likelihood of occurrence of a threat and the consequences of that threat or impact considering existing mitigation measures (Pickering and Cowley 2010). The precautionary principle is applied where there is a lack of scientific information on the potential level of risk. While threats acting at an individual level may have major consequences to that animal (such as the death of the individual), population-wide threats are considered to present a higher risk.
The risk matrix uses a qualitative assessment drawing on peer reviewed literature and the expert opinion of the author of this thesis. Levels of risk and the associated priority for action are defined as follows in and Table 6.2. Categories for likelihood are defined as follows:
Almost certain – expected to occur every year; Likely – expected to occur at least once every five years; Possible – might occur at some time; and Unlikely – such events are known to have occurred on a worldwide basis but only a few times.
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Table 6.1: Risk level and actions required.
Risk level Action required Very High Immediate additional mitigation action required Additional mitigation action and an adaptive management plan required, the High precautionary principle should be applied Obtain additional information and develop additional mitigation action if Moderate required Monitor the threat occurrence and reassess threat level if likelihood or Low consequences change
Table 6.2: Risk prioritisation.
Likelihood of Consequences occurrence No long-term (relevant to Minor Moderate Major Catastrophic effect species)
Almost certain Low Moderate Very high Very high Very high
Likely Low Moderate High Very high Very high
Possible Low Moderate High Very high Very high
Unlikely Low Low Moderate High Very high
Rare or unknown Low Low Moderate High Very high
6.5.2 Prioritisation of threats to east Australian humpback whales Table 6.3 provides an assessment of the threats facing EAH, including their likelihood and consequence. Table 6.4 summarises the prioritisation of threats to EAH based on the risk assessment.
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Table 6.3: Residual risk matrix for east Australian humpback whales.
Likelihood of Consequences occurrence No long- (relevant to Minor Moderate Major Catastrophic term effect species)
Almost certain Anthropogenic Vessel noise Likely disturbance Habitat and strike degradation Climate Entanglement Possible variability and Disease change Unlikely Pollution Whaling Over Rare or unknown exploitation of prey
Table 6.4: Summaries and priorities for management actions for east Australian humpback whales.
Priority Action required High Assessing and addressing anthropogenic noise: shipping, industrial and seismic surveys Addressing coastal and offshore development and operational impacts Assessing and addressing climate variability and change Addressing the potential for commercial whaling to recommence Moderate Assessing potential for vessel disturbance and ship strike Reducing entanglements Assessing potential for disease Assessing and addressing potential for pollution Assessing and addressing potential for over exploitation of prey
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6.6 EXISTING MANAGEMENT ACTIONS – INTERNATIONAL CONVENTIONS AND AGREEMENTS
Humpback whales are provided a degree of international protection through their listing in Appendix 1 of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), and also in Appendix 1 ‘Endangered Migratory Species’ of the Convention on the Conservation of Migratory Species of Wild Animals (CMS, Bonn Convention). Australia is a signatory to both CITES and the CMS.
In 2008, the International Union for Conservation of Nature (IUCN) reviewed the status of humpback whales on the Red List of Threatened Species. During this review, reflecting the recovery of humpback whales globally, the IUCN downgraded their global conservation status from a classification of ‘Vulnerable’ to that of ‘Least Concern’ (IUCN Red List - http://www.iucnredlist.org/details/13006/0). Despite the encouraging signs of recovery of most humpback whale populations globally, concerns remain about a number of discrete and small sub-populations for which information on status and trends in recovery are lacking or point to a slow or lack of recovery.
Overall, the current status and understanding of the recovery of humpback whales in Oceania is poor. The Oceania population includes whales from east Australia in the west to French Polynesia in the east. In 2008 the IUCN upgraded the classification of these populations, including east Australia, from Threatened to Endangered in (IUCN 2014). Even though the east Australian population of humpback whales is currently showing strong signs of recovery, they were listed as Endangered because it was not possible to estimate the recovery of EAH separately from the rest of Oceania due a lack of data on the locations of historic catches. By contrast, the western Australian population, which is also showing strong signs of recovery, is classified by IUCN as Least Concern as the recovery of this population could be adequately assessed.
In 2006, the CMS developed and agreed a Memorandum of Understanding (MoU) for the Conservation of Cetaceans and their Habitats in the Pacific Island Region. This MoU is a multilateral environmental agreement concluded under the auspices of the CMS in collaboration with the South Pacific Regional Environment Programme (SPREP). The MoU provides an international framework within the region for coordinated conservation efforts to improve the conservation status of Pacific Island Cetaceans and came into effect on 15 September 2006. The MoU covers 22 Pacific Island Nations. In addition, SPREP endorsed
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the Oceania Humpback Whale Recovery Plan (SPREP 2011) in 2012 as the primary instrument for guiding recovery actions in the South Pacific. Australia is a member and signatory to both SPREP and all their associated policy documents relevant to humpback whales. Australia is also a signatory to the United Nations Convention on Law of the Sea (UNCLOS). This convention affords highly migratory species, such as humpback whales, special protection.
As well as with CMS and UNCLOS, Australia is an active participant in CITES. CITES regulates the international trade in wild animals and plants in order to ensure their survival in the wild is not threatened. Within CITES, humpback whales are listed on Appendix 1, which lists species that are the most endangered. It is illegal to undertake international trade in species of Appendix 1, with the exception of scientific research.
Australia participates in several other international agreements that directly or indirectly relate to the conservation of marine mammals. Specifically, Australia is a founding member of the IWC and supported the introduction of a global moratorium on commercial whaling. Australia is the host country of the CCAMLR and is a key player in the Antarctic Treaty Consultative Meetings (ATCM). In addition Australia is a signatory to the Convention on Biological Diversity (CBD).
Australia is very active in these International Agreements in advocating for the protection and conservation of humpback whales internationally.
All whales, including humpback whales, are protected from commercial whaling through the moratorium on commercial whaling implemented by the IWC. The IWC has also established international sanctuaries in the Indian and Southern Oceans. However, member nations may issue special permits that allow whaling for scientific purposes (that is, scientific whaling), including within sanctuaries. Japan has an ongoing scientific whaling programme in Antarctic waters to the south of Australia and NZ since 1986 (when the moratorium first came into effect). This programme has primarily targeted minke and more recently fin whales. While humpback whales were added to the programme in 2005, none have been killed. In 2014 Australia successfully challenged the legality of the Japanese scientific whaling programme before the International Court of Justice (ICJ 2014). Although halting the Japanese JARPA II research programme that year, Japan recommenced scientific whaling under a revised (NEWREP-A) research programme, which targets 333 minke whales annually (Government of Japan 2014). Humpback and fin whales are not included
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in Japan’s lethal take under the new programme but are subject to non-lethal forms of sampling such as biopsy and photo-identification (Government of Japan 2014). There is potential for Japan to include the lethal take of humpback whales in future iterations of NEWREP-A.
There is a range of other international measures, including those administered by the International Maritime Organisation (for example, the International Convention of the Prevention of Pollution from Ships (MARPOL) 1973) which, while they are not directly related to the protection of whales, are management tools for some of the identified threats to EAH.
6.7 EXISTING MANAGEMENT ACTIONS - NATIONAL LEGISLATION AND MANAGEMENT ARRANGEMENTS
6.7.1 Commonwealth legislation The key environmental legislation of the Australian Commonwealth Government is the EPBC Act (Australian Government 1999). In conjunction with States and Territories, the Commonwealth Government uses this to coordinate a national scheme of environment and heritage protection and biodiversity conservation. The EPBC Act provides high levels of protection for whales and dolphins in Commonwealth waters and the Australian Whale Sanctuary. The Australian Whale Sanctuary starts at the seaward extent of the Australian state and territory waters three nautical miles from the coast and extends to the edge of Australia’s Exclusive Economic Zone (EEZ) at a distance of 200 nautical miles (approximately 370 kilometres) from the Australian coast. It also encompasses from the coast to the edge of the EEZ of the Australian Antarctic Territory and the five external territory islands: the Coral Sea Islands Territory; Heard and McDonald Islands; Norfolk Island; Cocos (Keeling) Islands; and Christmas Island.
The Australian Whale Sanctuary was established to protect all whales and dolphins found in Australian waters. It is illegal to kill, injure or interfere with a cetacean, including trading, taking, keeping, moving, harassing, chasing, herding, tagging, marking or branding of animals. The EPBC Act also makes the above activities an offence for Australians in international waters. Permits may be issued (such as for the purpose of research) by the Commonwealth Minister for the Department of the Environment.
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Humpback whales are currently listed as ‘vulnerable’ under the EPBC Act. The EPBC Act provides for recovery plans to be developed for the purposes of the protection, conservation and management of listed threatened species. Recovery plans must set out the recovery objectives and the actions required in order to achieve those objectives. The EPBC Act also requires that a review of recovery plans be undertaken at intervals of no longer than five years. A humpback whale recovery plan for the years 2005-2010 was previously developed by the Commonwealth and is currently being reviewed and updated.
Several other guidelines and policy statements to manage human interactions with whales are in place under the umbrella of the EPBC Act. These include the EPBC Act Policy Statement 2.1 – Interaction between offshore seismic exploration and whales: Industry guidelines and Australian National Guidelines for Whale and Dolphin Watching 2005 (Australian Government 2008a,b). The whale watching guidelines were developed by Commonwealth, State and Territory governments in order to standardise regulation and management of commercial and recreational whale watching and provide information on best practice. However, each State government manages whale watching in their own waters.
To regulate the impact of fishing on whales, including bycatch and entanglement, Australian, State and Territory governments are working together with the fishing industry and the Australian Fisheries Management Authority to develop methods to minimise these impacts. The Commonwealth Fisheries Management Act 1991 requires that any exploitation of fisheries resources and related activities are ecologically sustainable and that a precautionary principle is exercised. Under this Act, a National Policy on Fisheries Bycatch was endorsed in 1999 due to a concern over the take of non-target species in fishing. The policy aims to ensure that direct and indirect impacts on aquatic systems are considered in the development and implementation of fisheries management regimes.
Marine bioregional plans have been developed and approved under Section 176 of the EPBC Act for all Commonwealth waters around Australia. Each marine bioregional plan describes the marine environment and conservation values of the region, identifies and characterises the pressures affecting these conservation values, identifies regional priorities and outlines strategies to address them. As part of this process, humpback whales have been identified as representing a major conservation value in all bioregional plans.
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6.7.2 State and Territory legislation In addition to their protection under Commonwealth legislation, humpback whales are also protected throughout Australia under State and Territory legislation.
New South Wales legislation Listed as vulnerable under the Threatened Species Conservation Act 1995. Regulations for whale watching are provided in the NSW National Parks and Wildlife Amendment (Marine Mammals) Regulations 2006.
Northern Territory legislation Listed as Least Concern under the Territory Parks and Wildlife Conservation Act 2000.
Queensland legislation Listed as Vulnerable under the Nature Conservation (Wildlife) Regulation 2006. Whale watching is regulated under the Marine Parks Act 2004.
South Australian legislation Listed as Vulnerable under the National Parks and Wildlife Act 1972. Guidelines for whale watching and interacting with cetaceans are given in the National Parks and Wildlife (Protected Animals – Marine Mammals) Regulations 2010 under the National Parks and Wildlife Act 1972.
Tasmanian legislation Listed as Endangered under the Threatened Species Protection Act 1995. The Department of Primary Industries, Parks Water and Environment and the Tasmanian Parks and Wildlife Service provide whale watching guidelines that conform with the Australian National Guidelines for Whale and Dolphin Watching 2005.
Victorian legislation Listed as Threatened under the Flora and Fauna Guarantee Act 1988. Under the Wildlife Act 1975 it is an offence to kill, injure, take or interfere with a whale.
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Western Australian legislation Listed as Rare or likely to become extinct under the Wildlife Conservation Act 1950.
6.8 EXISTING MANAGEMENT ACTIONS – ASSESSMENT OF EFFECTIVENESS
Australia has a long-standing commitment to the conservation and management of cetaceans. Existing management actions are summarised below and critically assessed against the prioritised threats identified in Table 6.3.
Table 6.5 draws upon information from sections 6.6 and 6.7 to identify the ‘management tools’ and ‘main protection mechanisms’ used to protect humpback whales. A critical evaluation of the threats identified in Table 6.3 was undertaken against the current management tools in order to determine their effectiveness in addressing the identified threats. Management tools include international, national and state legislation and agreements, while the main protection mechanisms are the policies and systems implemented under these management tools, the intention of which is to address the identified threats. The ‘Effective?’ column, of Table 6.5 shows an assessment of the effectiveness of the current protection mechanisms in managing the identified threat. The ‘Limitations’ and ‘Potential improvements’ columns identify limitations of, and the potential for improvements in, the management tools and main protection mechanisms used to address and effectively manage the identified threats. This evaluation is the work of the author and was not part of the work commissioned by the Commonwealth Government as part of the preparation of the Conservation Management Plan for Australian humpback whales.
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Table 6.5: Assessment of management actions and their effectiveness for identified threats to east Australian humpback whales including limitations and potential improvements.
Threat Management tool Main protection Effective? Limitations Potential improvements mechanisms
High Priority
Anthropogenic EPBC Act Designated Maybe Current management tools have Potential for new best practice noise – Humpback whale shipping lanes limited ability to manage noise design for all new ships that shipping recovery plan Australian National impacts from shipping and in identify designs for minimising Marine Bioregional Guideline for whale particular the cumulative impacts noise impacts from commercial Planning (MBP) and dolphin of noise from a range of vessel- shipping activities. Maximum National watching based activities. noise output from all commercial shipping operating within high Representative Potential for significant increases conservation areas such as System of Marine in shipping into the future. Unsure breeding grounds during the Protected Areas of ability of current management breeding season (June to October) (NRSMPA) tools to manage increased shipping should be below the behavioural International in key areas (for example, breeding response threshold (120 dB re Marine ground within the Great Barrier 1µPa at 1m (Southall et al. 2007). Organisation Reef - GBR). (IMO) Monitoring required to assess the Recovery plans, which are required Australian potential of increase in noise levels to be developed under the EPBC Maritime Safety associated with the forecast Act for all threatened species, are Authority (AMSA) increase of shipping in the
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Threat Management tool Main protection Effective? Limitations Potential improvements mechanisms
not required to be independently breeding grounds within the Great monitored for their effectiveness. Barrier Reef.
In some States and in An independent panel of experts Commonwealth waters, there is no appointed to assess effectiveness current licencing system for of implementation of recovery commercial vessel-based whale plans. and dolphin watching. If impacts are detected then consideration should be given to seasonal restrictions on vessels using the main north/south shipping lane within the Great Barrier Reef if the ships noise output is above 120 dB re 1µPa at 1m.
Consideration for licencing systems for commercial whale and dolphin watching throughout Australia.
Anthropogenic EPBC Act Referral System Yes Neither EPBC Act nor NOPSEMA While there are requirements for noise - National Offshore Offshore Project deal well with cumulative impacts. sound transmission loss modelling industrial Petroleum Safety Proposal (OPP) (STLM) for some activities
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Threat Management tool Main protection Effective? Limitations Potential improvements mechanisms
and Environmental Policy Statement associated with industrial Management on ‘Offshore operations, the accuracy of these Authority aquaculture’ models can vary based on the (NOPSEMA) Policy Statement quality of the data on which the Humpback whale on ‘Wind farm model is generated. recovery plan industry’ All STLM should be validated by MBP empirical data collected at the start National of the activity. If the empirical data Representative do not support the STLM, then the System of Marine activity should be suspended until Protected Areas the STLM can be reassessed and State and Territory appropriate cetacean impact environmental mitigation measures put in place. legislation Anthropogenic EPBC Act Referral System Yes Based on the precautionary Following publication of results noise – seismic NOPSEMA Policy Statement principle due to lack of scientific from a behavioural response study surveys Offshore Petroleum 2.1 information on impacts. (BRAHSS), Policy Statement 2.1 and Greenhouse Offshore Project should be reviewed and updated Gas Storage Proposal (OPP) based on research results. (Environment) Currently Policy Statement 2.1 Regulations 2009 does not adequately address
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Threat Management tool Main protection Effective? Limitations Potential improvements mechanisms
operations during night time and periods of low visibility.
In 2013 the responsibility for assessing impacts of oil and gas activities was transferred from Department of the Environment (DOE) to NOPSEMA. An independent committee should be established to review the effectiveness of this new mechanism and its outcomes.
Coastal and EPBC Act Referral System Yes – currently, Neither system deals well with Monitor recent changes to offshore NOPSEMA Offshore Project however, effects of cumulative impacts. mechanisms of implementation – development recent changes to that is, an independent committee Humpback whale Proposal (OPP) for Present Australian Government is and mechanisms need to be established to review the recovery plan oil and gas pro-development and is currently operational be determined (for transfer of assessment of impacts MBP activities streamlining the approvals process impacts example, Referrals of development activities from NRSMPA MBPs focus on (including removing approvals will not be required DOE to State Government. State and Territory improving under EPBC Act from for offshore oil and environmental conservation and Commonwealth and delegating this gas activities and OPP legislation. sustainable use of activity to State authorities). marine resources, will replace them). and management of
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Threat Management tool Main protection Effective? Limitations Potential improvements mechanisms
human and industry This has the potential to result in interactions with inconstancies in the way marine assessment is undertaken and has environments the potential for increased impacts NRSMPA are from coastal and offshore managed primarily developments on humpback for biodiversity whales. conservation
Climate United Nations Australian No Uncertainty regarding the level of Government has just announced variability and Framework Domestic impact. that it will abolish the Carbon Tax. change Convention on Greenhouse Alternative strategies required to Climate Change legislation manage potential impacts. (UNFCCC) Kyoto Protocol Inter-governmental Panel on Climate Change (IPCC) Department of Climate Change and Energy Efficiency Whaling IWC IWC Moratorium Yes With the increase in whale Current vote buying tactics by EPBC Act on whaling numbers in some regions there has some countries at the IWC should
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Threat Management tool Main protection Effective? Limitations Potential improvements mechanisms
Action plan for Southern Ocean been growing interest to resume be addressed. Scientific whaling Australian Whale Sanctuary whaling on a sustainable basis. removed as a legitimate and legal Cetaceans Australian Whale Revision to IWC moratorium form of whaling. would be required to allow this. Sanctuary Further studies (using genetics) of Australia’s action Potential for unilateral scientific whale meat sold commercially to against Japan for whaling and illegal whaling (such determine species and scientific whaling as the activities of the Soviets region/population where whale in the International following the ban on taking came from. Court of Justice, humpback whales in the Southern although Japan has Hemisphere). resumed whaling Limited, if any policing of the via a revised Southern Ocean to ensure there are scientific no illegal whaling activities. programme
Moderate Priority
Vessel EPBC Act Development of Maybe Research required to quantify Research needs to be conducted disturbance Humpback whale guidelines for current level of, and potential for, into current level of, and potential and ship strike recovery plan reducing ship ship strike within Australian for, ship strike within Australian MBP collisions waters. waters. A review of current NRSMPA management practices would IMO follow and incorporate recommendations from research
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Threat Management tool Main protection Effective? Limitations Potential improvements mechanisms
AMSA National Ship (that is, go slow zones within Strike Strategy breeding areas during breeding under development season, consideration for early warning systems as used of Cape Cod USA).
Consideration for density of shipping to be reduced in key biological area (that is, Great Barrier Reef) during breeding season (June to October).
Entanglements Fisheries Code of Best Practise Maybe A high percentage of Research needs to be conducted Conduct guidelines and entanglements are unreported. into current level of entanglement taught rope policies within Australian waters. A review EPBC Act Research is required to quantify of current management practices Humpback whale Referrals the level of entanglement within would follow and incorporate recovery plan Policy Statement Australian waters. MBP on Offshore recommendations from research. NRSMPA Aquaculture Mandatory change to different lobster pot devices developed in USA.
Consideration given to a system whereby the surface line from lobster pots are not floating on the
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Threat Management tool Main protection Effective? Limitations Potential improvements mechanisms
surface all the time but contained on the seafloor and released using an acoustic release or other mechanism to retrieve the pot.
Disease CITES Wildlife Exotic No Australia currently has an existing The issue of appropriate Biosecurity Disease structure to deal with wildlife management tools to detect and Preparedness health issues, however, it is very manage disease needs to be further Program fragile. investigated.
Australian Wildlife Limited or no work currently being Australia needs a national body to Health Network undertaken to assess the level of ensure wildlife health is addressed. Australia has a impact within Australian waters. policy of not Also current management tools not releasing Antarctic really designed to address this species back into issue. wild after they have been in captivity in order to minimise disease transmission
Pollution EPBC Act Oil spill response Maybe Limited work currently being Further work needs to be MARPOL plans undertaken to assess the level of undertaken in order to identify impact within Australian waters. appropriate management tools to
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Threat Management tool Main protection Effective? Limitations Potential improvements mechanisms
State Government assess and manage the impacts of Legislation pollution on the EAH.
Over CCAMLR The application of Yes Ongoing monitoring of krill exploitation of the precautionary populations in the southern Ocean prey principle in the needs to be undertaken. The setting of quotas in potential for cumulative impacts the Southern including climate change and over Ocean. exploitation needs to be monitored.
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6.9 STATUS OF THE EAST AUSTRALIAN HUMPBACK WHALE POPULATION
6.9.1 General overview of listing criteria The EPBC Act is the Australian Government’s principal legislation for environmental protection. The EPBC Act protects Australia’s native species and ecological communities by providing for:
Identification and listing of species and ecological communities as threatened; Development of conservation advice and recovery plans for listed species and ecological communities; Development of a register of critical habitat; Recognition of key threatening processes; and Where appropriate, reducing the impacts of these processes through threat abatement plans.
Section 179 of the EPBC Act provides scope for a native species to be added to the list of threatened species. Species are nominated to the Department of Environment (DOE) and assessed by the Threatened Species Scientific Committee (the Committee) against specific criteria. Assessments of the conservation status of native species under the EPBC Act are made against statutory criteria, which are established under the EPBC Regulations 2000 (see Division 7.1 of the Regulations). These criteria are based on the IUCN threatened species criteria. Once assessed, the Committee makes a recommendation to the Minister for a native species to be listed as critically endangered, endangered or vulnerable if it meets any of the criteria.
A nomination to list or delist any native species can be made by any member of the public. At present, under the EPBC Act there is no formal review process for the assessment of the status of a species once it has been listed. A change in the listing status (including up or down listing) is only triggered by a nomination for a change or, at times, following a review of the Recovery Plan for the species. Garnett et al. (2011) have demonstrated that the current listing system under the EPBC Act, is not working effectively. They undertook a review of the current status of all native Australian bird species and subspecies according to IUCN (Red List) criteria. That assessment identified 54 bird species and subspecies that met the IUCN criteria for listing as threatened but were not listed as threatened under the EPC Act
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(Garnett et al. 2011). A further 22 species were identified as being listed under the EPBC Act but they no longer met the criteria. This issue needs to be addressed with a regular (for example, minimum of five-yearly) review of the threatened species status of all species listed under the EPBC Act.
If a listed species no longer meets the criteria, a nomination to remove it from the list can be submitted to DOE. The nomination is reviewed by the Committee in order to determine if the species should be removed from the list of threatened species under the EPBC Act. The nomination must provide evidence to demonstrate that the species no longer meets any of the five criteria for listing and, therefore, should not be considered threatened. In addition, a nomination to delist a species must provide evidence to demonstrate that the removal of conservation management programs for the species as a result of it being removed from the list of threatened species would not result in it becoming eligible for listing in the foreseeable future.
Typically an application for listing or delisting a species as a Threatened Species is assessed on a species level and individual populations are not assessed. However, the definition of a species under the EPBC Act includes sub-species and distinct populations that the Minister has determined to be species for the purposes of the Act. Therefore, the Minister has the discretion to assess individual, distinct populations for listing or delisting as Threatened Species. The Minister has assessed species at a population rather than species level on a number of occasions. For example, Koalas in Qld, NSW and the Australian Capital Territory are listed as Vulnerable, whereas significant populations in Victoria and South Australia are not listed as threatened (EPBC Threatened Species list – DOE Species Profile and Threats Database7).
Australian humpback whales were last assessed as Vulnerable under Section 178, and were a Listed Migratory Species under Section 209 of the EPBC Act in 2000. Sixteen years have passed since this review and there now exists increased scientific knowledge of Australian humpback whales. It is prudent and timely, therefore, to review this current knowledge and undertake a preliminary assessment of Australian humpback whales against the Threatened Species criteria in order to determine their current status. Since the focus of this thesis is the
7 http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=85104 accessed 8 March 2014
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EAH population (Breeding Stock E1), an assessment has been undertaken for this population only, with a justification for this individual population provided below.
DOE provides on their website a nomination form for the delisting of native species under the EPBC Act8. These criteria have been used in order to review the status of the EAH population under the EPBC Act. The following Sections include a full review of the current status of the EAH population against the EPBC Act criteria for Threatened Species.
6.9.2 Justification for individual listing of east Australian humpback whales Typically an application for listing or delisting a species as a Threatened Species is assessed on a species level nationally and individual populations (“part range”) are not assessed. However, there is a precedent for the Minister to assess a species at an individual population level (refer section 6.9.1).
Based on this precedent and for the following reasons, the Threatened Species status of the EAH has been assessed in this thesis at a population level:
The EAH population (Breeding Stock E1) is independent of the west Australian population (Breeding Stock D) and the population migrating past Norfolk Island (Breeding Stock E2); Humpback whales within Australian waters form relatively discrete breeding stocks with a relatively low incidence of migratory interchange between them. Garrigue et al. (2011a,b) documented a low level of interchange between Oceania and the east coast of Australia based on an extensive photo-identification analysis. This result is further supported by genetic analysis by Olavarría et al. (2006), which compared genetic samples from eastern Australia (E1) with those of Breeding Stocks D, E, F and G. They confirmed that there were significant differences at haplotype and nucleotide levels between eastern Australia and all other breeding stocks (including E2 New Caledonia, and E3 Tonga). Steel et al. (2011) also supports this finding following further genetic analysis of samples from the region. The low level of movement of whales between Oceania and eastern Australia based on Discovery mark data provides further evidence of this low level of migratory interchange (see Chapter 3);
8 http://www.environment.gov.au/biodiversity/threatened/nominations/forms-and-guidelines
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Populations within Australian waters are showing inconsistent recovery rates, with east and west Australian populations growing strongly but the Norfolk Island population appearing to grow slowly or not at all.
The argument exists that a joint assessment of the east and west Australian populations is appropriate since they both show strong signs of recovery in recent years. However, while both are growing strongly, the data sets are of differing quality and are not directly comparable. The trend data and population estimate for EAH is remarkably consistent over time with a very tight correlation between counts and year. By contrast, the current data available on the recovery of Breeding Stock D shows considerably more variation. The most recent (2008) population estimate for Breeding Stock D is 36,600 (95% CI: 30,310-50,190) with a trend estimate of 12.7% (CV 0.19). In addition, uncertainties associated with some assumptions of this study result in significantly less precision and confidence in current data (Hedley et al. 2009).
The population of humpback whales that migrates past Norfolk Island (reported to be part of Breeding Stock E2) is showing very limited, if any, signs of recovery from whaling (Paton et al. 2006). It appears to have a different recovery trajectory to both the EAH and Western Australian populations. This and the following evidence support the theory that the EAH and Breeding Stock E2 are different populations:
Chittleborough (1960) reported a decline in the mean length of humpback whales taken at whaling stations on the east coast of Australia in the late 1950s and early 1960s. Although he reports a reduction in the mean length of humpback whales taken at Norfolk during this period, he reports a higher mean length and age of humpback whales taken at Norfolk Island in comparison to those recorded for whaling activities on the east coast of Australia. While the size variation of humpback whales observed by Chittleborough (1960, 1965) could be a result of different whaling selectivity by the gunners for larger whales, Chittleborough attributes this difference in size to a possible indication of a real difference in the stock of the humpback whales migrating along the east coast of Australia and those passing Norfolk Island; A total of 135 humpback whales were marked at Norfolk Island with Discovery marks (Dawbin 1964; see Chapter 3). Of these, six marks were recovered. Five of the six marks were recovered at Norfolk Island, the last one was recovered in NZ
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(Cook Strait). An additional two marks originating from the feeding grounds (63° S, 139° E and 63° S, 149° E) in Area V were also recovered at Norfolk Island (Paton and Clapham 2006). This movement between Norfolk Island and NZ is supported by the report of a harpoon lost at Norfolk Island in the early 1900s and later recovered from a whale taken at the former whaling station at Whangamumu in Northern NZ (Dawbin 1956a). Discovery marking coordinated by Dawbin on humpback whales at New Caledonia (n=44) and Vanuatu (n=24) did not result in recovery of any Discovery marks from either region (Paton and Clapham 2006); Sighting surveys undertaken by Oosterman and Wicker from 2003 to 2006 resulted in very low numbers of whales sighted in comparison to historical sighting surveys coordinated by Dawbin in 1956 (Paton et al. 2006; Oosterman and Whicker 2013). It is difficult to make a direct comparison between recent and historical surveys, due to the fact that the methodology for the 1956 survey is not clear, and that the recent surveys are not a direct replication of the 1956 surveys. However, with those caveats in mind, the results indicate that humpback whales observed at Norfolk Island between 2003 and 2006 are well below the number observed during sighting surveys coordinated by Dawbin in 1956, and even below the catch per hour data (which will be an underestimate of the actual density of whales sighted) for the whaling operations between 1956-1962 reported by Chittleborough (1965). Given the maximum growth rate being observed in EAH, it makes it highly unlikely that these two populations share the same population growth rate and therefore are most likely separate; and A 2006 fluke photo-identification resight between New Caledonia and Norfolk Island strengthens the theory that Norfolk humpback whales could be related to the stock migrating past NZ as recent genetic and demographic evidence suggest a close relationship between NZ and New Caledonia humpback whales (Olavarria et al. 2006; Garrigue et al. 2000, 2002).
Based on the information provided, it is clear that the EAH population is distinct from both the west Australian and Norfolk Island populations and, therefore, should be assessed independently of the other two.
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6.9.3 Evaluation of east Australian humpback whales against listing criteria
Name of nominated species (or subspecies)
Scientific name: Megaptera novaeangliae
Common name: Humpback whale
Population: east Australian humpback whale population (Breeding Stock E1)
Category in which the species is currently listed
What category is the species currently Vulnerable listed in under the EPBC Act?
Is the species listed as threatened in any States or Territories?
Extinct: N/A
Extinct in the wild: N/A
Critically Endangered: N/A
Endangered: TAS
Vulnerable: NSW, Qld, SA, ACT
Conservation dependent: N/A
Rare/Least Concern: NT
Not listed: N/A
Other: Vic (Threatened); WA (Rare or likely to become extinct); Also listed as a Migratory Species under the EPBC Act
Eligibility against the criteria The EPBC Act and Regulations outline criteria for the assessment of a species for listing and delisting. These are based on the IUCN Red List Categories and Criteria, which are intended to be an easily and widely understood system for classifying species at high risk of global extinction. The general aim of the IUCN system is to provide an explicit, objective framework for the classification of the broadest range of species according to their extinction risk (IUCN 2012). The IUCN system uses five Criteria (A –E) to assess a species. The EPBC Act has largely adopted this system, using five criteria (1-5) in order to assess the current risk of extinction. To be considered eligible for listing, a species must be found to meet at
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least one of the five criteria. Conversely, to be considered for removal from the list, a species must be found to not meet any of the five.
While the Threatened Species Criteria under the EPBC Act and Regulations are adapted from the IUCN Red List Categories and Criteria (Version 3.1, 2001), the Committee appointed to assess nominations under the EPBC Act can be informed, but are not bound by, the indicative thresholds and requirements under the IUCN system. When assessing a species’ eligibility against the criteria, the Committee can exercise its judgement to give a practical meaning to the subjective terms of the criteria. The Committee does this by considering the information provided to it via the nomination form in the context of the species’ biology and relevant ecological factors, and having regard to the degree of complexity and uncertainty associated with that context and the information provided (DOE 2014).
A review of the status of EAH against the EPBC Act criteria was undertaken in order to assess whether or not they met any of them. This review and assessment is presented below.
EPBC Act – CRITERION 1: Reduction in numbers (based on any of A1 – A4)
A1. An observed, estimated, inferred or suspected population very severe (90%), severe (70%), or substantial (50%) size reduction over the last 10 years or three generations, whichever is the longer, where the causes of the reduction are clearly reversible AND understood AND ceased, based on (and specifying) any of the following:
(a) direct observation
(b) an index of abundance appropriate to the taxon
(c) a decline in area of occupancy, extent of occurrence and/or quality of habitat
(d) actual or potential levels of exploitation
(e) the effects of introduced taxa, hybridization, pathogens, pollutants, competitors or parasites.
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Taylor et al. (2007) estimates the generation period for humpback whales is 21.5 years. Therefore the last three generations equals approximately 64.5 years (that is, since 1949). There was a significant decline in the EAH population during the last three generations with the population estimated to reach as low as <1% of pre-exploitation size (for example, minimum population size of between 190 and 205 individuals in 1968 from a pre- exploitation size of 22,000 – 25,700; Jackson et al. 2009). This decline was largely due to illegal Soviet whaling activities in Antarctic waters in the late 1950s and early 1960s (Clapham et al. 2009).
Humpback whales are now internationally protected from whaling and are not the current focus of any whaling activities in the SH. Jackson et al. (2009) modelled estimated population trajectories for Oceania and EAH populations. The EAH population was assessed as recovering to estimated pre-exploitation size within the next ten years (or half of one generation) (Figure 6.7). The cause of the decline in humpback whale numbers is now well understood as the result of commercial whaling and, now that commercial whaling has ceased, the population should be, and is, recovering.
The absolute abundance of EAH was most recently estimated in 2010 and was reported as 14,522 whales (95% CI 12,777-16,504; Noad et al. 2011a). Extrapolating forward using the assumed population growth rate of 10.9% per annum (95% CI 10.5-11.3%: that is, the long- term growth rate for this population: Noad et al. 2006; 2008; 2011b), the population estimate for 2013 is 19,800. This figure is between 77% to 90% of the estimated pre-exploitation size for this population.
Criterion 1-A1 can be interpreted two ways relating to the application of “size reduction over the last 10 years or three generations, whichever is the longer”.
i) There has been a reduction in the size of the population at any time over the last ten years or three generations; and
ii) The population has declined based on a point estimate at ten years or three generations ago in comparison with the current point estimate.
The IUCN uses interpretation ii) (P. Harrison pers. comm. 14 March 2014). To do this, an abundance estimate three generations ago (64.5 years prior to 2013 = 1949) is directly compared with the current estimate of abundance. In 1949, there was very little whaling of humpback whales. The EAH population would have been close to the pre-exploitation
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estimate of 22,000 to 25,700 whales. The estimate for 2013 is approximately 19,800 whales (note this estimate is for population prior to the 2013 calving season). Applying this interpretation would result in an estimated decline between the two point estimates of 10% to 23%. The EAH population would, therefore, not be eligible for Criterion 1-A1.
However, while Criterion 1-A1 is based on an IUCN criterion, how to apply it is unclear. Application of interpretation i) of Criterion 1-A1 (that is the EAH population experienced a decline in numbers during the last 64.5 years), provides the following, very different, result. The EAH population has been through a severe decline >90% in the last three generations, it is presently recovering strongly and is estimated to reach pre-exploitation size within the next ten years (sometime in the 2020s). Furthermore, the causes of the reduction are clearly reversible AND understood AND have ceased. Despite its strong recovery, the EAH population has sustained a documented decline greater than 90% of pre-exploitation size in the last three generations. Following this argument, it is eligible for Criterion 1-A1 and should not be delisted.
The major collapse in whale numbers as a result of over exploitation occurred in the early 1960s (Figure 6.7). Population modelling by Jackson et al. (2009) indicates that the lowest estimated population size occurred in 1968. Given that Criterion 1-A1 relates to a ‘reduction over the last 10 years or three generations’, with the latter being 64.5 years for humpback whales, then applying interpretation ii) indicates that the EAH population will continue to meet Criterion 1-A1 until at least the year 2032 (1968 plus 64.5 years), irrespective of the actual number of whales in the population or its rate and level of recovery.
The two applications of Criterion 1-A1 provide opposite results. For the purposes of this assessment interpretation ii) has been applied, based on the following rationale:
The population has recovered so strongly (currently estimated to be at between 77% to 90% of pre-exploitation size; Jackson et al. 2009) and is continuing to do so; The population is expected to reach pre-exploitation size within the next ten years (Jackson et al. 2009); There is no evidence that the population will decline in the next 100 years;
The IUCN’s application of this interpretation for this criterion (P. Harrison pers. comm. 14 March 2014); and
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The ability for the Committee to exercise its judgement to give a practical meaning to the subjective terms of the criteria when assessing a species’ eligibility against the criterion.
It is the conclusion of this thesis, therefore, that Criterion 1-A1 is not met.
Figure 6.7: Population trajectories for Oceania and east Australia humpback whales showing changes in population abundance over time. Median trajectory (solid line) and 95% posterior probability intervals (dashed lines) are shown in blue for Oceania and red for east Australia. (Source: Jackson et al. 2009).
CRITERION 1-A2
An observed, estimated, inferred or suspected population very severe 80%, severe, 50% substantial, 30% size reduction over the last 10 years or three generations, whichever is the longer, where the reduction or its causes may not have ceased OR may not be understood OR may not be reversible, based on (and specifying) any of (a) to (e) under A1.
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Most of the comments provided for Criterion 1-A1 also apply to Criterion 1-A2. However, since the causes for the decline (commercial whaling) have ceased AND are clearly understood and well documented AND are considered to be reversible (as demonstrated by the strong recovery of the EAH population in recent years), it is the conclusion of this thesis that Criterion 1-A2 is not met.
CRITERION 1-A3
A population size reduction very severe 80%, severe 50%, substantial 30%, projected or suspected to be met within the next 10 years or three generations, whichever is the longer (up to a maximum of 100 years), based on (and specifying) any of (b) to (e) under A1.
The key element of criterion 1-A3 is whether or not a large decline in the EAH population is projected or suspected within the next three generations or 64.5 years.
Based on direct and reliable monitoring over the last 20 or so years, the EAH population is estimated to be increasing at a rate of over 10% (Bryden et al. 1996; Paterson et al. 2004; Noad et al. 2006, 2008, 2011b; Paton and Kniest 2011; see Chapter 1 and Chapter 4 for more detail). The most recent survey in 2010 (Noad et al. 2011a,b) confirms this trend and provides no evidence that the rate of growth is slowing. Furthermore, Jackson et al. (2009) modelled population trajectories for Oceania (comprising Breeding stocks E1, E2 and E3) and the EAH (Breeding stock E1). This work reported that the EAH population was currently estimated to be at between 77% and 90% of pre-exploitation size; is expected to reach pre-exploitation size within the next ten years; and there was no evidence of any level of population decline.
Given these findings, there is no indication of a projected OR suspected decline of the EAH population in the next ten years or three generations, and therefore it is the conclusion of this thesis that Criterion 1-A3 is not met.
Relating to Criterion 1-A3, an issue not considered by Jackson et al. (2009) was negative feedback on the population once it nears or reaches carrying capacity (K), which could be within the next ten years. In this instance, K is assumed to be at or around the estimated pre- exploitation size. If this occurs, then there is potential for the population to overshoot K,
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mortality rates to increase, and reproductive rates to decrease until the number of whales is approximately around K.
This phenomenon has been documented in Eastern North Pacific gray whales where the population reached K in the late 1990s (Punt and Wade 2010). This coincided with significantly increased mortality rates in 1999 and 2000 with an overall 29% estimated decline in numbers recorded before the population was observed to start increasing again (Figure 6.8) It is possible that the sequence of overshoot, followed by catastrophic mortality and then gradual increase may continue over a number of cycles before reaching equilibrium around K (Ouellet et al. 1994). While this issue could occur for the EAH population, it is premature and inappropriate to make an assessment about this and, therefore, it should not affect the failure of EAH to meet Criterion 1-A3.
Figure 6.8: Eastern North Pacific gray whale population size relative to carrying capacity (K). Source: Punt and Wade 2010.
CRITERION 1-A4
An observed, estimated, inferred, projected or suspected population size reduction very severe 80%, severe 50%, substantial 30% over any 10 year or three generation period, whichever is longer (up to a maximum of 100 years in the future), where the time period must include both the past and the future,
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and where the reduction or its causes may not have ceased OR may not be understood OR may not be reversible, based on (and specifying) any of (a) to (e) under A1.
Issues relevant to Criterion 1-A4 have been discussed under Criteria 1-A1 and 1-A3. Of specific relevance to Criterion 1-A4 is: there is no evidence of any projected or suspected decline into the future or since 1968; and the cause for the decline (commercial whaling) has ceased AND is clearly understood and well documented AND is considered to be reversible as demonstrated by the strong recovery in recent years. While a possible overshoot of K could lead to a decline once the EAH population approaches K, there is no evidence of this. It is the conclusion of this thesis, therefore, that Criterion 1-A4 is not met.
CRITERION 2: Geographic distribution (based on either of B1 or B2)
B1. Extent of occurrence estimated to be very restricted <100 km2, restricted <5000 km2 or limited < 20 000 km2
B2. Area of occupancy estimated to be very restricted <10 km2, restricted <500 km2 or limited <2000 km2
AND
Geographic distribution is precarious for the survival of the species, (based on at least two of a–c)
(a) Severely fragmented or known to exist at a limited location.
(b) Continuing decline, observed, inferred or projected, in any of the following:
(i) extent of occurrence
(ii) area of occupancy
(iii) area, extent and/or quality of habitat
(iv) number of locations or subpopulations
(v) number of mature individuals.
(c) Extreme fluctuations in any of the following:
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(i) extent of occurrence
(ii) area of occupancy
(iii) number of locations or subpopulations
(iv) number of mature individuals.
Figure 6.9 and Figure 6.10 provide an overview of the present distribution and range of humpback whales around mainland Australia and Antarctica. EAH only occupy the region indicated on the east coast of Australia and the region between 100⁰E and 160⁰W in Antarctica. The cumulative extent of these areas is at least an order of magnitude above 20,000 km2 and so the EAH population does not meet the conditions for Criteria 2-B1 or 2- B2. It is the conclusion of this thesis, therefore, that Criterion 2 is not met.
Figure 6.9: Known and inferred distribution of humpback whales around mainland Australia. Source: Childerhouse et al. (2013).
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Figure 6.10: Known and inferred distribution of humpback whales around Antarctica. Source: Childerhouse et al. (2013).
CRITERION 3: The estimated total number of mature individuals is very low <250, low <2500 or limited<10 000;
and either of (A) or (B) is true
(A) evidence suggests that the number will continue to decline at a very high (25% in 3 years or 1 generation (up to 100 years), whichever is longer), high (20% in 5 years or 2 generations (up to 100 years), whichever is longer) or substantial (10% in 10 years or 3 generations years), whichever is longer (up to 100 years) rate; or
(B) the number is likely to continue to decline and its geographic distribution is precarious for its survival (based on at least two of a – c):
(a) Severely fragmented or known to exist at a limited location.
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(b) Continuing decline, observed, inferred or projected, in any of the following:
(i) extent of occurrence
(ii) area of occupancy
(iii) area, extent and/or quality of habitat
(iv) number of locations or subpopulations
(v) number of mature individuals.
(c) Extreme fluctuations in any of the following:
(i) extent of occurrence
(ii) area of occupancy
(iii) number of locations or subpopulations
(iv) number of mature individuals
In answering this question include data and information on how the species meets the criteria, including the estimated total number of mature individuals if known.
Note: If the estimated total number of mature individuals is unknown but presumed to be likely to be >10 000 you are not required to provide an answer to either A or B as the species would be ineligible under this criteria.
If you are answering (B) as part of this criteria and have provided an answer to the second part of the criteria in Criterion 2 above you are not required to repeat the information provided in Criterion 2, just refer to it and add any additional information that may be relevant to this criterion.”
The key element of Criterion 3 is the ability to estimate the proportion of mature individuals within the EAH population.
Taylor et al. (2007) investigated for the IUCN the demographics of cetacean populations including the proportion of mature animals. They reviewed 58 cetacean species, including
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humpback whales and used an estimated rate of population growth of 5% for humpback whales, which is the rate documented for some Northern Hemisphere populations (Calambokidis et al. 2008). At this rate, the estimated proportion of mature animals within a population would be approximately 0.62. However, as the EAH population is increasing at close to 11% (rather than 5%) this proportion of mature animals is likely to be an overestimate. This is because a recovering population is expected to have far fewer mature animals than a stable population (Taylor et al. 2007). This is particularly relevant for long- lived species such as whales.
Given this potential overestimate, it is useful to explore other scenarios closer to the 11% population growth rate recorded for EAH. For example, Taylor et al. (2007) report an estimated 0.50 proportion of mature individuals for Harbour porpoise (Phocoena phocoena), which has a population growth rate of 11%, similar to that for EAH. While this is a useful exercise for illustrative purposes, given the huge variation in life history between humpback whales and harbour porpoises, the utility of this approach is limited. It does, perhaps, provide a lower bound on what might be expected from a rapidly growing population.
The most recent estimate of absolute abundance for EAH is from 2010: 14,522 whales (95% CI 12,777-16,504; Noad et al. 2011b). Assuming a population growth rate of 10.9% per annum, which is the long-term growth rate for this population and does not appear to be slowing, then extrapolating forward to 2013 using this rate of increase provides a current mean population estimate of 19,800.
Using Taylor et al.’s (2007) estimate of 0.62 to represent the proportion of mature humpback whales, leads to an estimate of 12,280 mature animals within the EAH population. However, using the lower estimate of 0.50 from harbour porpoises, yields an estimate of 9,900 mature animals. The very different life history parameters of humpback whales and harbour porpoises suggest that the number of mature animals indicated using the harbour porpoise proportion would likely be an underestimate for humpback whales. There is considerable uncertainty about where EAH are likely to lie within the range of the 0.50-0.62 proportions, however the range of these values will encapsulate the true value and even when using the most conservative value of 0.50 the estimated number of mature humpback whales is well above this EPBC Act criterion.
Based on the data available and applying a conservative approach, the EAH population is unlikely to be eligible for listing under Criterion 3 as of 2013. However, assuming:
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The current rate of population growth continues; The EAH population estimate is 21,970 (extrapolated to 2014 from the 2010 estimate); and Using the conservative value of 0.50 proportion of mature individuals.
Then there will be approximately 10,985 mature individuals, which is in excess of the 10,000 identified under Criterion 3 for listing.
Whether 0.50 or 0.62 is used as the estimate of proportion of mature individuals, Criterion 3-B relates to a requirement for a documented decline. This was discussed previously under Criterion 1-A3, and concluded that there is no indication of a projected OR suspected decline of EAH in the next ten years or three generations. Therefore, irrespective of whether or not the EAH population meets the threshold regarding the number of mature individuals (Criterion 3-A), it will not meet Criterion 3-B. It is the conclusion of this thesis, therefore, that Criterion 3 is not met.
CRITERION 4: Estimated total number of mature individuals
(a) Extremely low 50
(b) Very low <250
(c) Low <1000
In answering this question provide details on how the figure derived.
As outlined previously under Criterion 3, the number of mature individuals in the EAH population is most likely between 9,900 and 12,280 individuals. It is the conclusion of this thesis, therefore, that Criterion 4 is not met.
CRITERION 5: Probability of extinction in the wild based on quantitative analysis is at least:
(a) 50% in the immediate future, 10 years or three generations (whichever is longer); or
(b) 20% in the near future, 20 year or five generations (whichever is longer); or
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(c) 10% in the medium-term future, within 100 years.
In answering this question include data and information on how the species meets the criteria.
As outlined previously under Criterion 1-A3 and 1-A4, there is no evidence of any projected or suspected decline into the future or since 1968. While a possible overshoot of K could lead to a decline once the EAH population approaches K, there is no evidence for this. The only quantitative analysis undertaken for EAH was by Jackson et al. (2009), which showed strong growth for the next few decades and no evidence of a decline nor even a remote risk of extinction. It is the conclusion of this thesis, therefore, that Criterion 5 is not met.
CHANGES IN SITUATION
With regard for the listing criteria, how have circumstances changed since the species was listed that now makes it eligible for removal from the list?
Humpback whales in Australia were originally listed as Endangered under the Threatened Species Protection Act prior to 1995. It is unclear upon what this original assessment was based, however, many original listings were based on limited scientific data (I. Lawler pers. comm. 2013). In 1999, the EPBC Act was introduced and a review of the status of humpback whales was undertaken. At this stage, humpback whales were listed as Vulnerable, though, again, the information on which this determination was based is unclear and unavailable.
Since these assessments a considerable body of research has documented the recovery of the EAH population and demonstrates that it no longer meets any of the criteria for its current listing under the EPBC Act. Specifically, the population has recovered strongly (currently estimated to be between 77% and 90% of pre-exploitation size; Jackson et al. 2009) and is continuing to recover. Furthermore, the population is expected to reach pre-exploitation size within the next ten years and there is no evidence that the population will decline in the next 100 years (Jackson et al. 2009).
Given the positive signs of recovery, and this assessment of the status of the EAH population against the EPBC Act Threatened Species criteria, the Committee and the Environment Minister should give serious consideration to the delisting of this population.
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While there are some potential political sensitivities associated with delisting the EAH population, it will still be a listed Migratory Species and a Protected Species under the EPBC Act. As such, it will still be afforded complete protection. This recovery is good news and the Australian Government should promote it as a success story. Humpback whales are one of a few species, let alone an iconic one, to recover while so many others are in decline or facing extinction due to anthropogenic impacts.
Retaining the current threatened species listing of this population, despite its strong recovery, undermines the significance of listings for other truly threatened species that genuinely deserve listing and the added conservation measures associated with it.
6.10 RECOMMENDATIONS FOR FURTHER RESEARCH
This thesis investigates the population status, structure and migratory interchange of SHH with a specific focus on EAH. This research further contributes to the growing body of data documenting the recovery of this population. While this thesis addresses some of the outstanding management questions for EAH, other research topics would further support the improved conservation and management of this population. The research outlined below has been prioritised based on the likely benefits of the outcomes to the Comprehensive Assessment of Southern Hemisphere Humpback Whales (CASH), which the IWC is currently conducting. All the Very High Priority research activities have the potential to contribute to the CASH outcomes.
6.10.1 Very high priority research A stumbling block in the completion of the CASH is the complexity of the stock structure and the interchange between Breeding Stocks E and F. The IWC has delayed completing the formal assessment of these breeding stocks pending further information to assist with their assessment (Gales et al. 2011). The IUCN’s listing of the EAH population as Endangered results from a review of the Oceania population undertaken in 2008 (Childerhouse et al. 2008). Based on the information available at the time, the IUCN determined it was not possible to assess the Oceania population independently of the EAH. This was due to uncertainties of stock structure and migratory interchange between these populations.
It follows that the highest priority research would be to provide further information that assists the IWC in completing the CASH, especially in determining the stock structure of
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Breeding Stocks E and F, and the current level of connectivity between the E1 Breeding Stock and that of E2 and E3, as well as F and D.
Investigations of stock structure involving comparison of genetic samples collected on the east Australian migratory corridor with samples collected in the breeding grounds of Oceania (including New Caledonia, Tonga, American Samoa, French Polynesia and the Cook Islands) have been undertaken by Anderson (2013) and Schmitt et al. (2014). These studies tell part of the story, but there are scant samples from the east Australian breeding grounds within the Great Barrier Reef (GBR). It is possible that whales from another Breeding Stock (for example, E2 or E3) may be using the east Australian migratory corridor but not breeding within the GBR. If that is the case then the current population estimate from the east Australian migratory corridor (Stradbroke Island and Cape Byron) for the number of whales migrating along the east coast of Australia will potentially be an over estimate of the true Breeding Stock E1 population. To address this issue the following work should be undertaken:
1) Systematic genetic sampling within the E1 breeding grounds – GBR, as well as the east Australian migratory corridor (including during the northern and southern migration) and analyses to understand stock structure;
2) Detailed genetic comparison between samples collected in the E1 Breeding Grounds and those currently held for Breeding Stocks D, E2, E3 and F;
3) Satellite tagging of animals off northern NSW or South East Qld during the northern migration to determine the migratory destination of animals using the east Australian migratory corridor. Tagging should be undertaken across the migratory season and include a wide range of cohorts and reproductive status; and
4) Following access to the full data set of the Soviet (Discovery) Marking Scheme (SMS), undertake further investigation of Discovery mark and recovery data to assist in further clarifying migratory interchange between Breeding Stocks D, E1, E2, E3 and F.
6.10.2 High priority research The following research priorities also address other management questions:
1) It is important to maintain the land-based surveys from Stradbroke Island in order to monitor the recovery of the EAH population and assess any change in its
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recovery rate as it approaches K. The dataset collected over the last 30 years from Stradbroke Island is one of the best available on the recovery of a great whale species. Surveys should be conducted every three years over a minimum of eight weeks around the peak of the northern migration (see Noad et al. 2011c for justification of survey spacing and period);
2) The potential for non-breeding females not to undertake an annual migration to the breeding grounds, but to remain in the Southern Ocean (or elsewhere) may negatively bias the current population estimates for the breeding stock (Brown et al. 1995). Genetic sampling should be undertaken on the migratory corridor, using a survey design that minimises the potential for sampling bias (such as selecting for more obvious surface active pods, which usually contain a higher percentage of males to females). To address this potential for sampling bias, the research vessel should be directed to pods on a random basis by a land-based spotting team. Pods should be randomly selected independent of pod size and composition. Sampling should be undertaken throughout the migratory season to account for the non- random nature of the migratory patterns. Migration is composed as a sequence of age and reproductive classes with lactating females and yearlings the first to leave the Antarctic feeding grounds for the breeding grounds, followed by immature whales of both sexes, then mature males and resting females and finally pregnant females (Dawbin 1966, 1997). Genetic samples should be collected from all animals in a pod. Sampling should not be undertaken on the breeding grounds since males potentially remain on the breeding grounds for longer periods than females, which may result in an availability bias.
3) Research should be undertaken to further investigate life history parameters including survival rates, age at first calving and birth interval. This would best be done through photo-identification and genetic sampling techniques. These data can be used to further analyse recovery rates and would reduce reliance on Northern Hemisphere data, which may be inaccurate for this population.
4) There is potential for humpback whales to be negatively impacted by anthropogenic noise. The author is a co-investigator in a current major study (The Behavioural Response of Australian Humpback Whales to Seismic Surveys
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(BRAHSS)9. Following the completion of BRAHSS, results of this research should be reviewed and consideration given as to whether the EPBC Act ‘Policy Statement 2.1 Interaction between offshore seismic exploration and whales’ should be updated in order to ensure it reflects the new research findings. In addition to assessing the effects of seismic surveys on humpback whales, the effects of ship noise and other anthropogenic activities need to be understood. As a priority, shipping noise levels should be monitored within the shipping corridors off central Qld, in particular the region of the junction of Hydrographs Channel and the main north/south shipping channel (east of Hay Point) within the GBR. This area coincides with the highest density of the identified humpback whale calving grounds (Smith et al. 2012) and should be monitored as part of a long-term study to assess the potential for displacement of at risk cohorts (mother and calves) within the breeding grounds.
5) Another threat facing humpback whales is the potential for ship strikes. This is one of the main causes of anthropogenic mortality of baleen whales worldwide. Conservative estimates of the projected increase in vessels transiting the GBR have it at least doubling by 2020. Thus, the threat of ship strikes to whales may also increase. Humpback whales are one of the most frequently reported victims of vessel strikes worldwide, however, there has been little focus on the impacts of vessel strikes on whales in Australian waters. The primary objectives of research to address this management issue are to:
a. Review the modeling framework developed by Peel et al. (2015) to conduct a quantitative assessment of the risk of ship strikes to humpback whales in the GBR using current distribution data from the peak times of the breeding season; and
b. Determine the coastal distribution of humpback whales around major coastal and port areas in the GBR to assess temporal changes in whale distribution and assess the risk of ship strike in inshore areas.
9 www.brahss.org.au
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6.11 SYNTHESIS AND GENERAL CONCLUSIONS
This chapter reviewed and prioritised the current threats facing EAH and also undertook an assessment of the management issues associated with their long-term recovery. A key component of this was a review of the current status of this population under the EPBC Act Threatened Species listing criteria. This chapter:
1) Identified a long-term management objective for the recovery of the EAH population;
2) Reviewed current threats to the EAH population including a critical evaluation of risk;
3) Identified existing conservation and management measures in place in order to protect humpback whales with a focus on the EAH population;
4) Reviewed the current status of the EAH population against the EPBC Act criteria and made recommendations for listing or delisting; and
5) Made recommendations for further research to address gaps in the current knowledge of EAH.
6.11.1 Primary management objective Before being able to review and assess the conservation status of EAH it is important to determine a primary long-term management objective. A primary long-term management objective was developed based on the requirements of the EPBC Act and other national and international legislation and agreements to which Australia is signatory.
The primary long-term management objective for Australian humpback whales is:
Humpback whales within Australian waters recover to their pre‐exploitation levels of distribution and abundance, and they can be removed from the Threatened Species list under the EPBC Act.
Data presented here and in Chapter 3, Chapter 4, and Chapter 5, along with other supporting data, have successfully documented the recovery of the EAH population from the edge of extinction. This population is showing strong signs of recovery (currently estimated to be at between 77% and 90% of pre-exploitation size; Jackson et al. 2009) and is continuing to recover at a long-term population growth rate of over 10%. Furthermore, EAH are expected
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to reach pre-exploitation abundance within the next ten years and there is no evidence that the population will decline in the next 100 years (Jackson et al. 2009).
Based on the assessment undertaken here against the Threatened Species criteria under the EPBC Act, the EAH population no longer meets the criteria and should be delisted (see further discussion on this issue below). However, in relation to the primary long-term objective, while EAH no longer meet the Threatened Species criteria and should be removed from the EPBC Threatened Species list, they will still retain complete protection in Australian waters.
A detailed literature review regarding the potential anthropogenic threats to humpback whales and the expert opinion of the author were used to inform a risk matrix and risk prioritisation system, and to provide a qualitative assessment of anthropogenic threats faced by humpback whales. The critical review of anthropogenic threats identified that the key issues facing EAH are:
High priority Anthropogenic noise; Coastal and offshore developments and operation impacts; Climate change and variability; and Commercial whaling. Moderate priority Entanglement; Disease; Pollution; and Over-exploitation of prey (especially krill fisheries in Antarctica).
Threats were considered in isolation and cumulative effects were not taken into account although they are known to be potentially very important when investigating overall risk. Further work is required in order to fully understand the potential cumulative impacts of threats on EAH. While it could be argued that there is no evidence of an impact at the population level from anthropogenic activities (as the population is currently growing at or near to the maximum biological rate), it is important to fully understand and quantify threats in order to ensure the ongoing recovery of this population. If any threat does start impacting
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on population growth, then this work should assist in identifying it in a timely manner and developing an appropriate management response.
A critical review of the current management tools (national and international) was undertaken in order to identify gaps and shortcomings in the long-term management of this population. The significant legislation, agreements and other management tools that are available for managing the recovery of the EAH population include:
International IWC (International Convention for the Regulation of Whaling 1946); IUCN; CMS; and CCAMLR. National EPBC Act 1999 (including the EPBC Act Referral process); EPBC Act Policy statement 2.1 Interaction between offshore seismic exploration and whales; Australian National Guidelines for whale and dolphin watching 2005; and Threatened Species Recovery plans.
The management tool that has had the single biggest influence on the recovery of the EAH population is the ban on killing humpback whales in commercial whaling operations, which was implemented by the IWC. This single management tool has allowed this population to recover from the edge of extinction in a relatively short time period for a species that is long- lived and has a low reproductive rate. Other legislation such as the EPBC Act provides a complementary framework to manage a number of the potential threats within Australian waters. However, it appears that none of the identified threats are having a significant influence on the recovery of the population as it is continuing to recover at or near the maximum biological rate for the species.
There appear to be shortcomings in the current level of protection from effects (disease, pollution, anthropogenic noise and ship strike) resulting from shipping, climate variability and change, and entanglements. Current management tools appear to have limited capability to detect and manage the potential impacts of some of these factors. The EPBC Act requires recovery plans (or in the case of threatened cetacean species DOE has now adopted the
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framework of Conservation Management Plans (CMPs) used by the IWC) to be prepared for all threatened species. However, a major shortcoming of this process is the lack of independent monitoring of the effectiveness of plans resulting in resources being committed to drafting plans and actions that have never been implemented. Recovery plans and CMPs are necessary and can be very effective when implemented fully. They are also much more effective when the implementation is coordinated though a recovery team that includes relevant experts and independent members (see Martin et al. 2012). Further work is needed to identify appropriate management tools to assess and manage the identified potential impacts stated above on the EAH.
Humpback whales are currently listed as ‘Vulnerable’ under the EPBC Act threatened species listing. While typically an application for listing or delisting is assessed on a species level and individual populations are not assessed, the definition of a species under the EPBC Act includes sub-species and distinct populations that the Minister has determined to be species for the purposes of the Act. Therefore, the Minister has the discretion to assess individual distinct populations for listing or delisting as Threatened Species. A precedent has been set with the listing of koalas at a local population level.
Genetic, photo-identification and population growth rate data indicate that the EAH population is separate from others found in Australian waters. For the purposes of this thesis, a review of the status of the EAH population on its own was undertaken against the EPBC Act Threatened Species criteria. A review of the EAH population against the EPBC Act Threatened Species criteria indicated that the species does not meet any of the five criteria. This indicates that it should be delisted. Of the five criteria, it clearly did not meet four. There is, however, potential for more than one interpretation of the fifth, Criterion (1-A1). For this criterion, the author believes the correct interpretation is that consistent with the application of the IUCN system whereas the alternate interpretation was less credible and robust.
In this thesis, Criterion 1-A1 was taken to mean a specific decline of sufficient magnitude since three generations ago (that is, a direct comparison between the population size 64.5 years ago with the current population size). However, Criterion 1-A1 could also be interpreted to mean a decline of sufficient magnitude recorded at any time over the last three generations (any time over the last 64.5 years). These interpretations lead to opposite outcomes. The former leads to delisting while the latter to listing. In addition, and of
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importance to the criterion, the cause of this decline (commercial whaling) is understood, has ceased and is clearly reversible, which is true for both interpretations.
Given their positive signs of recovery and the finding herein regarding the EPBC Act Threatened Species criteria, the Committee and the Environment Minister should give serious consideration to the delisting of the EAH population.
While there are some potential political and societal sensitivities associated with delisting, the EAH population will still be a listed Migratory Species and a protected species under the EPBC Act and, therefore, will still be afforded complete protection. This recovery of the EAH population is good news. The Australian Government should promote this recovery as a success story since it is one of the few species (and an iconic one), to recover while so many others are in decline or facing extinction due to anthropogenic impacts. Retaining the current threatened species listing of this population, despite its strong recovery, undermines the significance of listings for other truly threatened species that genuinely deserve listing and the added conservation measures associated with it. It also means that potentially limited resources for threatened species are allocated to species that genuinely require them rather than EAH which appear not to be in such need.
This thesis makes clear recommendations for further research that address outstanding management questions. The proposed research focusses on issues of stock structure and migratory interchange associated with Breeding Stocks E and F. This information will assist the IWC in completing the assessment of humpback whales in the Southern Hemisphere. In addition, the resulting data will assist managers (within Australian Government and the IWC) in making informed decisions to ensure the long-term conservation and protection of EAH.
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CHAPTER 7 GENERAL DISCUSSION, SYNTHESIS AND CONCLUSIONS
7.1 GENERAL DISCUSSION
This thesis investigates the population status, structure and migratory interchange of Southern Hemisphere humpback whales (SHH) with a specific focus on the east Australian humpback whale population (EAH). The aims of this thesis are to:
1) Document the movement patterns of EAH based on existing and previously unpublished Discovery mark data with a view to developing more robust models of stock structure to improve management and conservation of SHH stocks;
2) Estimate the recovery rate of EAH from systematic land-based counts;
3) Estimate abundance of EAH using multi-year capture-recapture analysis, and single-year, multi-point capture-recapture analysis; and
4) Undertake a review and assessment of management actions and their influence on recovery of EAH including a review of the threats and the current status of this population under the Environment Protection and Biodiversity Conservation Act (1999) (EPBC Act) and Threatened Species Listing under this Act.
Key data and analyses used in this thesis include:
Deployment and recovery information from Discovery mark tags (Chapter 3); Estimates of the population growth rate of EAH from systematic land-based counts at Cape Byron (Chapter 4); Abundance estimates of EAH in 2005 using a single year multi-point and multi- year photo-identification capture-recapture analysis (Chapter 5); and An assessment of threats, management tools and the status of EAH including a review of the current listing under the Threatened Species criteria of the EPBC Act (Chapter 6). This thesis reports and summarises an extensive body of research undertaken by the author and documents the movement patterns, recovery and management of humpback whales on the east coast of Australia. This research contributes to the growing body of data
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documenting the positive recovery of this population. In this chapter the key findings of this thesis, and their implications for management, are discussed. Further research to build on the findings of this thesis is also outlined. This research will contribute to addressing some remaining stock structure uncertainties and will assist the International Whaling Commission (IWC) in completing the Comprehensive Assessment of Southern Hemisphere Humpback Whales (CASH).
7.2 MIGRATORY INTERCHANGE AND STOCK STRUCTURE
The relationship and connections between breeding and feeding grounds for most SHH populations is not well understood. This presents a challenge for the accurate assessment of stock structure and, perhaps most importantly, makes it difficult to estimate accurately the pre-exploitation size of these populations. An understanding of pre-exploitation population size is an essential element in understanding and assessing present population status (that is, the level of recovery). Not having this information limits the effectiveness of ongoing management to ensure the recovery of these depleted populations. Discovery marks are the only source of historical information that can be used to elucidate the historic stock structure of SHH. While Discovery marks have some limitations, (for example, unequal deployment and recovery effort, non-reporting of recoveries by illegal Soviet whaling), they also provide a useful dataset that can improve our understanding of SHH in a way that few other data can.
Discovery marks have confirmed links between Breeding Stocks C, D and E and their putative feeding grounds in the Antarctic to the south of them. Discovery mark data indicates that SHH do form relatively discrete groups through strong linkages between breeding grounds within the longitudinal boundaries of the feeding areas. There is a relatively low incidence of large-scale movement between feeding areas, perhaps with the exception of Breeding Stock E, which appears to have a more broadly dispersed system of interchange between multiple breeding and several feeding areas.
The dispersal of whales from Breeding Stock E has a wide distribution beyond what was originally thought to be their putative feeding areas in Area V. That is, extending from Antarctic Area IV to Area I covering a range of approximately 175⁰ of longitude (nearly half the globe). Discovery mark data have documented a much wider distribution of whales from Breeding Stock E than was previously known. Additional recent research (including genetic data (Steel et al. 2008; Anderson 2013; Constantine et al. 2014), photo-identification data
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(Garrigue et al. 2004, 2011a,b; Franklin et al. 2008; Robbins et al. 2011; Constantine et al. 2014) and satellite tag data (Gales et al. 2010) shows a similar pattern of interchange that is consistent with the historical movements reported from Discovery marks. Overall, data from all of these sources consistently point to a low level of interchange. The data from this thesis were presented by the author to the IWC CASH process and were a critical source of information in that forum. Specifically, they were used to reduce the number of plausible stock structure hypotheses, to develop scenarios for the allocation of historic catch from feeding grounds to Breeding Stocks and were a significant component used to define SHH stock structure.
These data, combined with other data now available (including genetic, photo-identification and satellite tag data), indicate that revisions are potentially required to the IWC stock boundaries in the Antarctic in order to allow for the improved and more realistic allocation of historical catch data to breeding stocks. In addition to these data, recent genetic data have indicated the potential for significant genetic structure among humpback whales migrating northward along the east coast of Australia. This suggests a more complex structure than previously thought, which may support the Valsecchi et al. (2010) theory of mixing of animals from neighbouring populations during the northern migration (Anderson 2013; Schmitt et al. 2014). This information is important as it has implications for the assessment of population recovery based on land-based counts and also for the completion of the CASH stocks.
7.3 POPULATION GROWTH RATE
The CASH process undertaken by the IWC involves an in-depth evaluation of the status of whale stocks. It includes the examination of issues such as current stock size, recent population trends, carrying capacity and productivity. This thesis provides valuable information on the recent population trend for EAH during their northward migration between 1998 and 2004. The annual rate of increase observed for humpback whales migrating north past Cape Byron between 1998 and 2004 is calculated to be 11.0% (95% CI 2.3–20.5). This estimate has a large CI, most likely due to the short survey period (two weeks). Given that there is considerable inter-annual variation in the timing of migration, and that the survey does not cover the total migration period, the survey may not have always coincided with the peak of migration. In addition Chapter 4 has demonstrated that in some years (1999 and 2003) the main migratory corridor was further offshore than usual, thus
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reducing sightability of humpback whales. One other factor that may contribute to inter- annual variation is the potential for genuine variation in the number of whales that may migrate from year-to-year. This is supported by the theory of Brown et al. (1995), that non- breeding females may not migrate every year. Notwithstanding the large CIs, this estimate is consistent with results recorded at Point Lookout, North Stradbroke Island (134 km north of Cape Byron) by two independent but comparable land-based surveys.
These population growth rates approach or exceed the theoretical maximum for this species (Best 1993; Brandao et al. 1999; Bannister and Hedley 2001; Clapham and Zerbini 2006; IWC 2008). The data used to derive these maxima, however, are based on life history estimates for Northern Hemisphere humpback whales (NHH). These Northern Hemisphere (NH) stocks have lower observed population growth rates than those recorded for SH (IWC 2008), and therefore it is not surprising that EAH estimates are higher than the maximum rates reported for NHH. Interestingly, these SH estimates are remarkably consistent over time (Noad et al. 2011a,b).
Recent analysis of genetic data has indicated the potential for significant genetic structure among northward migrating humpback whales on the east coast of Australia. This suggests a more complex structure than previously thought (Anderson 2013; Schmitt et al. 2014). This conclusion provides some support for the theory proposed by Valsecchi et al. (2010) of the mixing of individuals from neighbouring populations during the northern migration. Consistent with this, is the suggestion by Clapham and Zerbini (2006) that the rapid growth rate of EAH (Breeding Stock E1) may be a result of immigration from other populations. While this latter theory is possible, the South Pacific Whale Research Consortium (SPWRC) recently tested it by undertaking an assessment of fluke identification photographs collected throughout Oceania (Breeding Stocks E1, E2, E3 and F). This analysis, coupled with the recovery of Discovery marks from this region (see Chapter 3) and genetic data (Olavarría et al. 2006; Steel et al. 2008), indicates a very low level of interchange between eastern Australia and the Oceania region. These data, therefore, do not support the theory of Clapham and Zerbini (2006) (Paton and Clapham 2006; Garrigue et al. 2011a,b).
Brown et al. (1995) reported a significant bias in the sex ratio of humpback whales sampled off the east coast of Australia during northward migration. They suggest that not all animals migrate every year as there is little reason for females who are not calving or mating to make the long migration. This may mean that, depending on environmental conditions, there may
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be inter-annual variation in the proportion of females undertaking migration, which in turn may lead to variation in survey counts. This issue remains unresolved with respect to EAH but has the potential to bias survey results between years. Further research (such as a structured un-biased genetic sampling design of all cohorts on the east Australian migratory corridor to assess the potential sex imbalance) is required in order to address this issue and the issue of stock structure for north migrating humpback whales on the east coast of Australia.
Differences in apparent population recovery rates across the South Pacific provides further evidence for isolation between breeding populations. Comparisons from recent sighting surveys in Fiji, New Zealand and Norfolk Island (Gibbs et al. 2003; Childerhouse and Gibbs 2006; Paton et al. 2006) with historical sighting data and whaling records (Dawbin 1956a,b, 1959, 1964) indicate that there is a lack or very slow rate of recovery in these regions of the South Pacific. By contrast, the EAH population is increasing at the rate of 10-11% per annum (see Chapter 4; Noad et al. 2008).
7.4 CURRENT POPULATION ESTIMATE
In addition to current data on trend, a current population estimate is important information required for the CASH process undertaken by the IWC. The research undertaken in this thesis provides two population estimates based on photo-identification capture recapture methods. The first estimate is a multi-point single year (2005) population estimate using photo-identification data collected at Byron Bay, Hervey Bay and Ballina. The second estimate is a multi-year population estimate using photo-identification data collected at Byron Bay between 1999 and 2005.
The two studies produced very similar population estimates of 7,041 (95% CI: 4,075- 10,008) for the multi-point capture-recapture estimate for 2005 and 7,390 (95% CI: 4,040- 10,739) humpback whales for the multi-year single-point estimate for 2005. These results are also consistent with Noad et al.’s (2008) land-based distance sampling estimate of 9,683 whales (95% CI: 8,556-10,959) for 2007 for this same population. The Noad et al. (2008) estimate, when extrapolated backwards using an annual increase rate of 10.9%, would give an estimate for 2005 of 7,873 (95% CI: 6,597-8,911).
The two estimates reported in this thesis have different assumptions and are potentially subject to different bias to those of the land-based distance sampling estimate. The fact that
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all three studies obtained comparable results provides considerable confidence in the estimates. However, a number of factors (such as, the possibility of a mixed stock being present within the northern migration; and the potential for a percentage of the females within the population not undertaking a migration every year) should be considered in determining the current status of the EAH.
Further research is required in order to determine if there is a sex bias (such as 2.39 males to 1 female) as Brown et al. (1995) has suggested. They speculated that the bias was a result of the non-migration of non-breeding females but another possible explanation is that their result could be due to a sampling bias associated with their methodology (social pods, which typically contain a higher number of males than females, are much easier to detect than single animals or small pods). The apparent sex bias could also be associated with males being more available for sampling as a result of having a longer residence time in the breeding grounds. Brown et al.’s (1995) theory is supported by Chittleborough (1965) who found that the sex ratio from commercial whaling at east coast whaling stations was similar (2.1 males to 1 female). In this instance, there was potential for a considerable sex bias as whalers selected against obviously pregnant females and females with calves. If there is a true male sex bias on the migratory corridor, then the estimates from Point Lookout at Stradbroke Island (Noad et al. 2011a,b) and the mark recapture estimate for 2005 (Chapter 5) would potentially provide an underestimate of the EAH population.
The other major factor that may bias population estimates is the possibility of a mixed stock migrating north along the east coast of Australia with some whales splitting off north of the study sites and heading east to other breeding grounds in the South Pacific. While satellite tag and photo-identification data do not support this theory, the genetic data are consistent with it. If there are individuals from other Breeding Stocks utilising the east Australian migratory corridor, then all three of the estimates for the EAH population will be an overestimate of the true number of EAH.
Another issue worthy of discussion is that of the current carrying capacity (K) in comparison to the historical K. This understanding is central because recovery is measured against pre- exploitation population size, which is assumed to be the historical K. If K is presumed to be dynamic, then the pre-exploitation population size could be different (higher or lower) and the present K may be completely unrelated to the historic values.
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While we have an approximation of historical K for EAH (Jackson et al. 2009), this figure may not be very accurate. The models from which this figure was derived are very sensitive to the allocation of historical catch data between the breeding stocks (Jackson et al. 2009). As there are a number of uncertainties in relation to the allocation of catches within the region (including over 7,000 illegal Soviet catches that remain impossible to allocate), this figure should only be considered an indicative K for this population. In addition, the environment in which humpback whales now live has substantially changed from that likely to be present prior to the modern whaling era. In the last century, there have been significant changes to the habitat and ecosystem of EAH including:
During the 20th Century, a total of 2,019,000 whales (inducing humpback whales) were reported taken from the Southern Ocean ecosystem; Krill are now being commercially harvested; Impacts of global warming are being felt; Increased anthropogenic development on the migratory corridors and breeding grounds; Increases in ocean noise and shipping activity; Increased offshore infrastructure and fishing activities; and The potential cumulative impacts of some or all of these factors.
These factors have the potential, both individually and collectively, to positively and/or negatively influence K for SHH populations. Therefore current K may be significantly different to what it was. Ongoing monitoring of the recovery of the EAH population is essential to assess their long-term rate of recovery and any potential change in this rate as EAH reach the estimated historical K in the near future. Consistent and ongoing data collection is critical to understand if and when EAH reach K. The time at which the EAH population reaches K will only be determined a considerable time after the fact. Regardless, it will be a challenge to determine the cause of any decline in population growth rate. A major question will be: is the population reaching current K or are other negative anthropogenic or natural factors starting to impact on EAH and, thus, slow growth? Research that works towards answering this question would be useful.
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7.5 THREATS AND STAUS OF EAST AUSTRALIAN HUMPBACK WHALES
This thesis critically reviewed and prioritised the current threats facing EAH and also undertook an assessment of the management issues associated with their long term recovery. A key component of this was to review the current status of this population under the EPBC Act Threatened Species listing criteria. A major aim of this work was to integrate all the research undertaken in this thesis with existing knowledge and to develop applied recommendations and observations about EAH that can be used to better conserve and manage their protection.
The review of anthropogenic threats identified that the key ones facing EAH are:
High priority Anthropogenic noise; Coastal and offshore developments and operation impacts; Climate change and variability; and Commercial whaling. Moderate priority Entanglement; Disease; Pollution; and Over-exploitation of prey.
These threats were only considered in isolation, cumulative effects were not taken into account. Further work is required in order to fully understand the potential cumulative impacts of these anthropogenic threats. While it could be argued that there is no evidence of an impact at the population level from anthropogenic activities (as the population is currently growing at or near to the maximum biological rate), it is important to fully understand and quantify threats in order to assure the ongoing recovery of this population. If any threat does start impacting on population growth, then this should assist in identifying it in a timely manner and developing an appropriate management response.
A critical review of the current management tools (national and international) was undertaken to identify gaps and shortcomings in the long-term management of this population. There appears to be shortcomings in the current level of protection associated
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with disease and pollution. Current management tools appear to have limited capability to detect and manage the potential impacts of these factors. Further work is needed in order to identify appropriate management tools to assess and manage these impacts on the EAH.
Humpback whales are currently listed as “Vulnerable” under the EPBC Act threatened species listing. A review of the status of the EAH population against the EPBC Act threatened species criteria (the criteria) has confirmed that they are recovering strongly, at or near the maximum biological rate for the species (currently estimated to be at between 77% to 90% of pre-exploitation size; Jackson et al. 2009), and are expected to reach their estimated pre-exploitation within the next ten years.
While there is some question as to the correct interpretation of criterion 1-A1, it has been interpreted here to be a specific decline of sufficient magnitude since three generations ago (a direct comparison between the population size 64.5 years ago with the current population size). However criterion 1-A1 could also be interpreted to mean a decline of sufficient magnitude recorded at any time over the last three generations (64.5 years). These interpretations will lead to opposite outcomes under this criterion in that the latter interpretation leads to a listing and the former leads to a delisting. For the purposes of this assessment the former interpretation has been applied in this thesis, based on the following considerations:
The population has recovered so strongly (currently estimated to be at between 77 to 90% of pre-exploitation size; Jackson et al. 2009) and is continuing to do so; The population is expected to reach pre-exploitation size within the next ten years (Jackson et al. 2009); There is no evidence that the population will decline in the next 100 years; The International Union for Conservation of Nature’s use of this interpretation for criterion 1-A1 (P. Harrison pers. comms. 14 March 2014); and The ability for the Threatened Species Scientific Committee to exercise its judgement to give a practical meaning to the subjective terms of the criteria when assessing a species’ eligibility against the criterion.
Therefore EAH do not meet criterion 1-A1 through a direct comparison between the population size 64.5 years ago (the last three generations) with the current population size and the cause of this decline (commercial whaling) is understood, has ceased and is clearly reversible.
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Given the positive signs of recovery and the finding herein regarding criterion 1-A1, the Threatened Species Scientific Committee and the Environment Minister should give serious consideration to the delisting of this population.
While there are some potential political and societal sensitivities associated with delisting, the EAH population will still be a listed Migratory Species and a protected species under the EPBC Act and, therefore, will still be afforded complete protection. The recovery of the EAH population is good news. The Australian Government should promote this recovery as a success story since it is one of the few species (and an iconic one), to recover while so many others are in decline or facing extinction due to anthropogenic impacts. Retaining the current threatened species listing of this population, despite its strong recovery, undermines the significance of listings for other truly threatened species that genuinely deserve listing and the added conservation measures associated with it.
This thesis identifies recommendations for further research that address outstanding management questions. The resulting data will assist managers (within Australian Government and the IWC) in making informed decisions to ensure the long-term conservation and protection of EAH.
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REFERENCES
Acevado A, Smultea MA (1995). First records of humpback whales including calves at Golfo Dulce and Isla del Coco, Costa Rica, suggesting geographical overlap of northern and southern hemisphere populations. Marine Mammal Science 11: 554-560.
Adobe Systems Incorporated (2005). Optimum strategies for using Adobe Photoshop CS2 in scientific and medical imaging. Adobe Systems Incorporated, San Jose, CA.
Anderson M (2013). Genetic connectivity within eastern Australian humpback whales and their relationship to adjacent South Pacific and Indian Ocean stocks. PhD thesis, Southern Cross University.
Anderson M, Steel D, Franklin W, Franklin T, Paton D, Burns D, Harrison P, Baverstock PR, Garrigue C, Olavarria C, Poole MM, Hauser N, Constantine R, Thiele D, Clapham P, Donoghue M, Baker CS (2010). Microsatellite genotype matches of eastern Australian humpback whales to Area V feeding and breeding grounds. Paper to the Scientific Committee of the International Whaling Commission, Agadir, Morocco, June 2010. SC/62/SH7.
Anonymous (undated). Report of the International Whaling Commission, Annex J, SC/25/1.
Anonymous (2003a). Appendix 7 to the IWC Report - Report of the Intersessional Group - Work required to complete assessment of Southern Hemisphere humpback whales.
Australian Government (1999). Commonwealth Environment Protection and Biodiversity Conservation Act 1999. Canberra, Australia.
Australian Government (2008a). EPBC Act Policy Statement 2.1 – Interaction between offshore seismic exploration and whales. Canberra, Australia. 14pp.
Australian Government (2008b). Australian National Guidelines for whale and dolphin watching 2005. Canberra, Australia, 20pp.
Baker CS (2000). Migrating Molecules-genetic diversity and difference among humpback whales worldwide. In 'Humpback Whale Conference 2000'. Brisbane, Queensland Museum.
Baker CS, Flórez-González L, Abernethy B, Rosenbaum HC, Slade RW, Capella J, Bannister JL (1998). Mitochondrial DNA variation and maternal gene flow among humpback whales of the Southern Hemisphere. Marine Mammal Science: 14(4) 721-737.
Baker CS, Gilbert DA, Weinrich MT, Lambertsen R, Calambokidis J, McArdle B, Chambers GK, O’Brien SJ (1993). Population characteristics of DNA fingerprints in humpback whales (Megaptera novaeangliae). Journal of Heredity 84: 281-290.
Baker CS, Herman LM (1984) Seasonal contrasts in the social behavior of the humpback whale. Cetus 5: 14- 16.
Page 202
Baker CS, Lento GM, Cipriano F, Palumbi SR (2000). Predicted decline of protected whales based on molecular genetic monitoring of Japanese and Korean markets. In Proceedings of the Royal Society. London. 1191-1199.
Baker CS, Palumbi SR, Lambertsen RH, Weinrich MT, Calambokidis J, O'Brien SJ (1990). Influence of seasonal migration on geographic distribution of mitochondrial DNA haplotypes in humpback whales. Nature 344: 238-240.
Baker CS, Slade RW et al. (1994). Hierarchical structure of mitochondrial DNA gene flow among humpback whales Megaptera novaeangliae, world-wide. Molecular Ecology 3(4): 313-327.
Bannister JL (2005). Intersessional Working Group on Southern Hemisphere humpback whales: revised tables by breeding stock (as at 1 May 2005). Paper SC/57/SH11 presented to the IWC Scientific Committee, June 2005, Ulsan, Korea (unpublished). 15pp.
Bannister JL, Hedley SL (2001). Southern Hemisphere group IV humpback whales: their status from recent aerial survey. Memoirs of the Queensland Museum 47(2): 587-598.
Baraff LS, Weinrich MT (1993). Separation of humpback whale mothers and calves on feeding ground in early autumn. Marine Mammal Science 9: 431-434.
Barlow J, Clapham PJ (1997). A new birth-interval approach to estimating demographic parameters of humpback whales. Ecology 78: 535-546.
Bejder L, Samuels A, Whitehead H, Gales N, Mann J, Connor R, Heithaus M, Watson-Capps J, Flaherty C, Krützen M (2006). Decline in relative abundance of bottlenose dolphins (Tursiops sp) exposed to long- term disturbance. Conservation Biology 20(6): 1791-1798.
Best PB (1993). Increase rates in severely depleted stocks of baleen whales. ICES Journal of Marine Science 50(3): 169-186.
Best PB (2001). A note on the age at sexual maturity of humpback whales. Journal of Cetacean Research and Management (Special Issue) 3: 71-73.
Braithwaite JE, Meeuwig JJ, Jenner CS (2012). Estimating cetacean carrying capacity based on spacing behaviour. PLoS ONE 7(12):e51347.
Brandao A, Butterworth DS, Brown MR (1999). Maximum possible humpback whale increase rates as a function of biological parameter values. Journal of Cetacean Research and Management (Supplement) 2: 192-193.
Brown MR (1996). Population biology and migratory characteristics of east Australian humpback whales Megaptera novaeangliae. Ph.D. thesis, University of Sydney. 322pp.
Brown KE (2009). Fine-scale distribution of humpback whales (Megaptera novaeangliae) on their southern migration past Cape Byron, northern NSW. Honours thesis, Southern Cross University, Lismore, Australia. pp.1-92.
Page 203
Brown MR (1997) Population biology and migratory characteristics of east Australian humpback whales Megaptera novaeangliae. PhD thesis, University of Sydney. 322pp.
Brown MR, Corkeron PJ, Hale PT, Schultz KW, Bryden MM (1995). Evidence for a sex-segregated migration in the humpback whale (Megaptera novaeangliae). Proceedings of the Royal Society of London, Series B 259: 229-234.
Brown MR, Field MS, Brown CE, Bryden MM (2003). Rates of increase for east Australian humpback whales, Megaptera novaengliae, from 1981-2000. Paper SC/55/SH21 presented to the IWC Scientific Committee, May 2003.
Brown SG (1956). Whale Marks Recently Recovered. Norsk Hvalfangst-Tidende 12: 45.
Brown SG (1957). Whale marks recovered during the Antarctic whaling season 1956/57. Norsk Hvalfangst- Tidende 46(10): 555-559.
Brown SG (1977). Whale marking: a shot review. In: A Voyage of Discovery: George Deacon 70th Anniversary Volume (ed. M. Angel). Pergamon Press, Oxford. Pp. 569-581.
Brown SG (1978). Whale marking Techniques. P. 71-80 In: B. Stonehouse (ed) Animal Marking: Recognition Making of Animals in Research. Macmillan Press Ltd, London. 257 pp.
Bryden M (1981). Survey of humpback whales (Megaptera novaeangliae) off eastern Australia, 1981. Australian National Parks and Wildlife Service Research Report.
Bryden M (1985). Studies of humpback whales (Megaptera novaeangliae), Area V. Studies of sea mammals in south latitudes. Proceeding of the 52nd ANZAAS Congress. J. K. Ling and M. M. Bryden. Sydney, Australia: 115-124.
Bryden MM, Brown MR, Field MS, Clarke ED, Butterworth DS (1996). Survey of humpback whales (Megaptera novaeangliae) off eastern Australia, 1996. Report prepared for the Australian Nature Conservation Agency, Canberra (unpublished). 77pp.
Bryden MM, Kirkwood GP, Slade RW (1990). Humpback whales, Area V. An increase in numbers off Australia’s east coast. In Antarctic Ecosystems. Ecological Change and Conservation. (eds. Kerry KR, Hempel G) pp. 277, Springer-Verlag: Berlin, Heidelberg).
Bryden M, Slade R (1987). Survey of humpback whales (Megaptera novaeangliae) off eastern Australia, 1987. Australian National Parks and Wildlife Service Research Report.
Buckland ST (1990). Estimation of survival rates from sightings of individually identifiable whales. Report of the International Whaling Commission (Special Issue) 12: 149-153.
Buckland ST, Breiwick JM (2002). Estimated trends in abundance of eastern Pacific gray whales from shore counts (1967/68 to 1995/96). Journal of Cetacean Research and Management 4(1): 41-48.
Buckland ST, Burnham KP, Augustin NH (1997). Model selection: an integral part of inference. Biometrics 53: 603-618.
Page 204
Buckland ST, Duff EI (1989). Analysis of the Southern Hemisphere minke whale mark-recovery data. Reports of the International Whaling Commission (Special Issue) 11: 121-143.
Burns D (2010). Population characteristics and migratory movements of humpback whales (Megaptera novaeangliae) identified on their southern migration past Ballina, eastern Australia. PhD thesis Southern Cross University.
Burns D, Brooks L, Harrison P, Franklin T, Franklin W, Paton D, Clapham P (2014). Migratory movements of individual humpback whales photographed off the eastern coast of Australia. Marine Mammal Science. 10.1111/mms.12057. 30, 562–578.
Calambokidis J, Barlow J (2004). Abundance of blue and humpback whales in the eastern North Pacific estimated by capture-recapture and line-transect methods. Marine Mammal Science 20(1): 63-85.
Calambokidis J, Cubbage JC, Steiger GH, Balcomb KC, Bloedel P (1990). Population estimates of humpback whales in the Gulf of the Farallones, California. Report of the International Whaling Commission (Special Issue) 12: 325-333.
Calambokidis J, Falcone EA, Quinn TJ, Burdin AM, Clapham PJ, Ford JKB, Gabriele CM, LeDuc R, Mattila D, Rojas-Bracho L, Straley JM, Taylor BL, Urbán JR, Weller D, Witteveen BH, Yamaguchi M, Bendlin A, Camacho D, Flynn K, Havron A, Huggins J, Maloney N, Barlow J, Wade PR (2008). SPLASH: structure of populations, levels of abundance and status of humpback whales in the North Pacific. Final report for Contract AB133F-03-RP-00078. U.S. Dept of Commerce. 57pp.
Calambokidis J, Steiger GH, Straley JM, Herman LM, Cerchio S, Salden DR, Urban JR, Jacobsen JK, Von Ziegasar O, Balcomb KC, Gabriele CM, Dalheim ME, Uchida S, Ellis G, Miyamura Y, De Guevara PLP, Yamaguchi M, Sato F, Mizroch SA, Schlender L, Rasmussen K, Barlow J, Quinn TJ (2001). Movements and population structure of humpback whales in the North Pacific. Marine Mammal Science 17(4): 769-794.
Castro C, Kaufman G, Maldini D (2011). A preliminary review of skin conditions and other body anomalies observed on humpback whales (Megaptera novaeangliae) from Ecuador. Paper SC/63/SH18 presented to the IWC Scientific Committee, May 2011, Tromsø, Norway (unpublished). 7pp.
Cawthorn M (1999). The changing face of New Zealand’s Whaling Policy. In Whaling and Anti-Whaling Movement, ICR.
Ceccarelli DM (2009). Impacts of plastic debris on Australian marine wildlife, report by C&R Consulting to the Australian Government Department of the Environment, Water, Heritage and the Arts, Canberra.
Chaloupka M, Osmond M, Kaufman G (1999). Estimating seasonal abundance and survival rates of humpback whales in Hervey Bay (east coast Australia). Marine Ecology Progress Series 184: 291-301.
Chao A, Huggins R (2005). Classical closed-population capture-recapture models. In: Steven C Amstrup, Trent L McDonald, Bryan FJ Manly (eds) Handbook of Capture-Recapture Analysis. Princeton University Press, NJ.
Page 205
Chao A, Lee SM, Jeng SL (1992). Estimating population size for capture-recapture data when capture probabilities vary by time and individual animal. Biometrics 48: 201-216.
Chapman DG (1974). Status of the Antarctic rorqual stocks. pp. 218-38. In: Schevill WE (eds). The whale problem, a status report. Harvard University Press, Massachusetts. x+419pp.
Childerhouse S, Gibbs N (2006). Preliminary report for Cook Strait humpback whale survey winter 2006. Unpublished report WGNHO-264433 to Department of Conservation, PO Box 10-420, Wellington, New Zealand. 6pp.
Childerhouse S, Jackson J, Baker CS, Gales N, Clapham PJ, Brownell Jr RL (2008). Megaptera novaeangliae (Oceania subpopulation). In: IUCN 2008. 2008 IUCN Red List of Threatened Species.
Childerhouse SJ, Paton D, Rekdahl M (2013) Draft Conservation Management Plan for humpback whales. Prepared for the Department of Sustainability, Environment, Water, Population & Communities. 59pp.
Chittleborough RG (1958a). Australian catches of humpback whales. Commonwealth Scientific and Industrial Research Organization, Division of Fisheries and Oceanography, Commonwealth of Australia, Cronulla, Sydney.
Chittleborough RG (1958b). The breeding cycle of the female humpback whale (Megaptera nodosa). Australian Journal of Marine and Freshwater Research 9: 3-18.
Chittleborough RG (1959a). Australian humpback whales 1958, Part 1. Analysis of Catches; Part 2. Whale Marking and Recoveries. Commonwealth Scientific and Industrial Research Organization, Cronulla, Sydney.
Chittleborough RG (1959b). Australian marking of humpback whales. Norsk Hvalfangst-Tidende 48, 47-55.
Chittleborough RG (1960). Australian catches of humpback whales. Commonwealth Scientific and Industrial Research Organization, Division of Fisheries, Cronulla, Sydney.
Chittleborough RG (1965). Dynamics of two populations of the humpback whale, Megaptera novaeangliae (Borowski). Australian Journal of Marine and Freshwater Research 16(1): 33-128.
Clapham PJ (1992). Age at attainment of sexual maturity in humpback whales, Megaptera novaeangliae. Canadian Journal of Zoology 70: 1470-1472.
Clapham PJ (2000). The humpback whale. In 'Cetacean Societies'. (eds Mann J, Connor R, Tyack P, Whitehead H) pp. 173-196, University of Chicago Press: Chicago.
Clapham PJ, Baker CS (2009). Whaling, Modern. In: Encyclopaedia of marine mammals 2nd Edition. (eds) WR Perrin, B Wursig and JGM Thewissen. Academic Press, pp. 1239-1243.
Clapham P J, Barlow J, Bessinger M, Cole T, Mattila D, Pace R, Palka D, Robbins J, Seton R (2003). Abundance and demographic parameters of humpback whales from the Gulf of Maine, and stock definition relative to the Scotian Shelf. Journal of Cetacean Research and Management 5:13-22.
Page 206
Clapham PJ, Mayo CA (1987). Reproduction and recruitment of individually identified humpback whales, Megaptera novaeangliae, observed in Massachusetts Bay, 1979-1985. Canadian Journal of Zoology 65: 2853-2863.
Clapham P, Mayo C (1990). Reproduction of humpback whales, Megaptera novaeangliae, observed in the Gulf of Maine. In Individual techniques to estimate population parameters: Special Issue 12. (eds H P.S., MS A. and D G.P.), IWC.
Clapham PJ, Mead JG (1999). Mammalian Species, Megaptera novaeangliae. Mammalian Species 604: 1-9.
Clapham P, Mikhalev Y, Franklin W, Paton D, Baker S and Brownell RL Jr. (2005). Catches of humpback whales in the Southern Ocean, 1947-1973. Paper SC/57/SH6 presented to the IWC Scientific Committee, June 2005, Ulsan, Korea (unpublished). 13pp.
Clapham PJ, Mikhalev Y, Franklin W, Paton D, Baker CS, Ivashchenko YV, Brownell RL Jr. (2009). Catches of humpback whales, Megaptera novaeangliae, by the Soviet Union and other nations in the Southern Ocean. 1947-1973. Marine Fisheries Review 71(1): 39-43.
Clapham PL, Wetmore SE, Smith TD, Mead JG (1999). Length at birth and at independence in humpback whales. Journal of Cetacean Research and Management 1: 141-146.
Clapham P, Zerbini A (2006). Is social aggregation driving high rates of increase in some Southern Hemisphere humpback whale populations? Paper SC/58/SH3 presented to the IWC Scientific Committee, May 2006, St Kitts and Nevis, West Indies (unpublished). 12pp.Constantine R, Russell K, Gibbs N, Childerhouse S, Baker CS (2006). Photo-identification of humpback whales in New Zealand waters and their migratory connections to breeding grounds of Oceania. Marine Mammal Science 23(3): 715-720.
Constantine R, Steel D, Allen J, Anderson M, Andrews O, Baker CS, Beeman P, Burns D, Charrassin JB, Childerhouse S, Double M, Ensor P, Franklin T, Franklin W, Gales N, Garrigue C, Gibbs N, Harrison P, Hauser N, Hutsel A, Jenner C, Jenner MN, Kaufman G, Macie A, Mattila D, Olavarría C, Oosterman A, Paton D, Poole M, Robbins J, Schmitt N, Stevick P, Tagarino A, Thompson K, Ward J (2014). Remote Antarctic feeding ground important for east Australian humpback whales. Marine Biology DOI 10.1007/s00227-014-2401-2.
Cox TM, Ragen TJ, Read AJ, Vos E, Baird RW, Balcomb K, Barlow J, Caldwell J, Cranford T, Crum L, D’Amico A, D’Spain G, Fernández A, Finneran J, Gentry R, Gerth W, Gulland F, Hildebrand J, Houserp D, Hullar T, Jepson PD, Ketten D, Macleod CD, Miller P, Moore S, Mountain DC, Palka D, Pongranis P, Rommel S, Rowles T, Taylor B, Tyack P, Wartzok D, Gisiner R, Meads J, Benner L (2006). Understanding the impacts of anthropogenic sound on beaked whales. Journal of Cetacean Research and Management 7(3): 177-187.
Croteau EK (2010). Causes and Consequences of Dispersal in Plants and Animals. Nature Education Knowledge 3(10): 12.
Dawbin B (1959). New Zealand and South Pacific whale marking and recoveries to the end of 1958. The Norwegian Whaling Gazette No 5: 213-238.
Page 207
Dawbin WH (1956a). The migrations of humpback whales which pass the New Zealand coast. Transactions and Proceedings of the Royal Society of New Zealand. 84: 147-196.
Dawbin WH (1956b). Whale marking in the South Pacific waters. Norsk Hvalfangst-Tidende 45: 485-508.
Dawbin WH (1964). Movements of humpback whales marked in the southwest Pacific Ocean 1952 to 1962. Norsk Hvalfangst-Tidende 53(3): 68-78.
Dawbin WH (1966). The seasonal migratory cycle of humpback whales. pp 145-70. In: Norris KS (eds) Whales, Dolphins, and Porpoises. University of California Press, Berkeley and Los Angeles. xv+789pp.
Dawbin WH (1997). Temporal segregation of humpback whales during migration in Southern Hemisphere waters. Memoirs of the Queensland Museum. 42(1):105-138.
DOC (2013). Code of conduct for minimising acoustic disturbance to marine mammals from seismic survey operations. Department of Conservation, NZ. www.doc.govt.nz.
DOE (2014). Guidelines for assessing the Conservation status of Native Specie according to the EPBC Act and Regulations 2000. http://www.environment.gov.au/ system/files/pages/d72dfd1a-f0d8-4699-8d43- 5d95bbb02428/files/guidelines-species.pdf.
Dominello T, Norris T, Yack T, Ferguson E, Oswald J, Hom-Weaver C, Jumar A, Nissen J, Bell J (2013). Vocalisation behaviors of minke whales in relation to sonar in the planned Undersea Warfare Training Range of Jacksonville, FL. 20th Biennial Conference on the Biology of Marine Mammals, Dunedin, NZ. 2pABb5.
Doney SC, Ruckelshaus M, Duffy JE, Barry JP, Chan F, English CA, Galindo HM, Grebmeier JM, Hollowed AB, Knowlton N, Polovina J, Rabalais NN, Sydeman WJ, Talley LD (2012). Climate change impacts on marine ecosystems. Annual Review Marine Science 4: 11−37.
Donovan GP (1989). Preface to the volume The Comprehensive Assessment of Whale Stocks. Report of the International Whaling Commission (Special issue) 11: iii-iiv.
Donovan GP (1991). A review of IWC stock boundaries. Report of the International Whaling Commission (Special Issue) 13: 39-68.
Emmel TC (1976). Population Biology. Harper and Row Publisher, London.
Erbe C, McPherson C (2012). Acoustic characterisation of bycatch mitigation pingers on Queensland Shark Control nets. Endangered Species Research 19: 109-121.
Findlay KP (2001). A review of humpback whale catches by modern whaling operations in the Southern Hemisphere. Memoirs of the Queensland Museum 47(2): 411-420.
Findlay KP, Best PB (1996a). Assessment of heterogeneity in sighting probabilities of humpback whales within viewing range of Cape Vidal, South Africa. Marine Mammal Science 12(3): 335-353.
Page 208
Findlay KP, Best PB (1996b). Estimates of the numbers of humpback whales observed migrating past Cape Vidal, South Africa, 1988-1991. Marine Mammal Science 12(3): 354-370.
Flórez-González L, Capelia AJ, Haase B, Bravo GA, Felix F, Gerrodette T (1998). Changes in winter destinations and the northernmost record of south eastern Pacific humpback whale. Marine Mammal Science 14: 189-196.
Forestell PH, Kaufman GD, Chaloupka M (2003). Migratory characteristics of humpback whales (Megaptera novaeangliae) in Hervey Bay and the Whitsunday Islands, Queensland, Australia: 1993-1999. Final Report to the Environment Protection Agency, Queensland Parks and Wildlife Service, Brisbane, Australia.
Franklin W (2014). Abundance, population dynamics, reproduction, rates of population increase and migration linkages of eastern Australian humpback whales (Megaptera novaeangliae) utilising Hervey Bay, Queensland. PhD thesis: Southern Cross University, Lismore, NSW.
Franklin W, Franklin T, Brooks L, Gibbs N, Childerhouse S, Burns D, Paton D, Donoghue M, Garrigue C, Russell K, Constantine R, Mattila DK, Poole M, Robbins J, Hauser N, Anderson M, Olavarría C, Leaper R, Jackson J, Baker S, Noad M, Harrison P, Baverstock P. Clapham P (2008). Eastern Australia (E1 breeding grounds) may be a wintering destination for Area V Humpback Whales (Megaptera novaeangliae) migrating through New Zealand waters. Report to the IWC: SC/60/SH3.
Franklin W, Franklin T, Brooks L, Gibbs N, Childerhouse S, Smith F, Burns D, Paton D, Garrigue C, Constantine R, Poole M, Hauser N, Donoghue M, Russell K, Mattila DK, Robbins J, Oosterman A, Leaper R, Harrison P, Baker CS, Clapham P (2012). Antarctic waters (Area V) near the Balleny Islands are a summer feeding area for some eastern Australian Breeding Stock E(1) humpback whales (Megaptera novaeangliae). Journal of Cetacean Research and Management 12(3): 321-327.
Franse R (2005). Effectiveness of Acoustic Deterrent devices (pingers). Report to the EUCC 33pp.
Gabriele CM, Straley JM, Mizroch SA, Baker CS, Craig AS, Herman LM, Glockner-Ferrari D, Ferrari MJ, Cerchio S, von Ziegesar O, Darling J, McSweeney D, Quinn TJ, Jacobsen JK (2001). Estimating the mortality rate of humpback whale calves in the central North Pacific Ocean. Canadian Journal of Zoology 79: 589-600.
Gabriele CM, Straley JM, Neilson JL (2007). Age at first calving of female humpback whales in southeastern Alaska. Marine Mammal Science 23(1): 226-239.
Gales N, Bannister JL, Findlay K, Zerbini A, Donovan GP (2011). Humpback Whales: status in the Southern Hemisphere. Journal of Cetacean Research and Management (Special Issue) 3.
Gales N, Double M, Robinson S, Jenner C, Jenner M, King E, Gedamke J, Childerhouse S, Paton D (2010). Satellite tracking of Australian humpback (Megaptera novaeangliae) and pygmy blue whales (Balaenoptera musculus brevicauda). Paper submitted to the Scientific Committee of the IWC SC/62/SH21.
Page 209
Gales N, Double MC, Robinson S, Jenner C, Jenner M, King E, Gedamke J, Paton D and Raymond B (2009). Satellite tracking of southbound East Australian humpback whales (Megaptera novaeangliae): challenging the feast or famine model for migrating whales. Paper submitted for consideration by the IWC Scientific Committee. SC/61/SH17. pp. 7.
Garland EC, Goldizen AW, Rekdahl ML, Constantine R, Garrigue C, Daeschler Hauser N, Poole MM, Robbins J, Noad MJ (2011). Dynamic horizontal cultural transmission of humpback whale song at the ocean basin scale. Current Biology 21: 687-691.
Garnett ST, Szabo JK, Dutson G (2011). The action plan for Australian birds (CSIRO Melbourne).
Garrigue C, Aguayo A, Amante-Helwig VLU, Baker CS, Caballero P, Clapham P, Constantine R, Denkinger J, Donoghue M, Florez- Gonzalez L, Greaves J, Hauser N, Olavarría C, Pairoa C, Peckham H, Poole M (2002). Movements of humpback whales in Oceania South Pacific. Journal of Cetacean Research and Management 4(3): 255-260.
Garrigue C, Constantine R, Poole MM, Hauser N, Clapham P, Donoghue M, Russell K, Paton D, Mattila DK, Robbins J, Baker, CS (2011a). Movement of individual humpback whales between wintering grounds of Oceania (South Pacific), 1999 to 2004. Journal of Cetacean Research and Management (Special Issue) 3: 257-281.
Garrigue C, Dodemont R, Steel D, Baker CS (2004). Organismal and ‘gametic' recapture using microsatellite genotyping confirm low abundance and reproductive autonomy of humpback whales on the wintering grounds of New Caledonia. Marine Ecology Progress Series 274: 251-262.
Garrigue C, Forestell P, Greaves J, Gill P, Naessig P, Patenaude NM, Baker CS (2000). Migratory movement of humpback whales (Megaptera novaeangliae) between New Caledonia, East Australia and New Zealand. Journal of Cetacean Research and Management 2(2): 101-110.
Garrigue C, Franklin T, Constantine R, Russell K, Burns D, Poole MM, Paton D, Hauser N, Oremus M, Childerhouse S, Mattila DK, Gibbs N, Franklin W, Robbins J, Clapham P, Baker CS (2011b). First assessment of interchange of humpback whales between Oceania and the east coast of Australia. Journal of Cetacean Research and Management (Special Issue) 3: 269-274.
Garrigue C, Franklin T, Russell K, Burns D, Poole MM, Paton D, Hauser N, Oremus M, Constantine R, Childerhouse S, Mattila D, Gibbs N, Franklin W, Robbins J, Clapham P, Baker CS (2007). First assessment of interchange of humpback whales between Oceania and the east coast of Australia. Paper SC/59/SH15 presented to the IWC Scientific Committee, May 2007 (unpublished). 9pp.
GBRMPA (2013). Ports and shipping information sheet – May 2013. http://elibrary.gbrmpa.gov.au/jspui/handle/11017/969.
Gibbs N, Childerhouse S (2000). Humpback whales around New Zealand. Conservation Advisory Science Notes 287: 32pp. Department of Conservation. Wellington, NZ.
Page 210
Gibbs N, Childerhouse S (2004). First report of the recovery of humpback whales in New Zealand waters. Unpublished. Available from the Department of Conservation, PO Box 10, 420 Wellington, New Zealand.
Gibbs N, Paton D, Childerhouse S (2006). Assessment of the current abundance of humpback whales in the Lomaiviti Island Group of Fiji and a comparison with historical data. Paper presented to the IWC Scientific Committee SC/A06/HW34.
Gibbs N, Paton DA, Childerhouse S, McConnell H, Oosterman A (2003). Final Report of a survey of whales and dolphins in the Lomaiviti Island Group, Fiji 2003. Final report to the Department of Environment and Heritage, Canberra, Australia (unpublished). Available from the Australian Government, GPO Box 787, Canberra, ACT 2601, Australia.
Gill JA, Norris K, Sutherland WJ (2001). Why behavioural responses may not reflect the population consequences of human disturbance. Biological Conservation 67(2): 265-268.
Glockner D (1983). Determining the sex of humpback whales (Megaptera novaeangliae) in their natural environment. In Communication and Behavior of Whales (ed. Payne R) pp. 447-464 Westview Press: Boulder, CO.
Government of Japan (2014). Research Plan for New Scientific Whale Research Program in the Antarctic Ocean (NEWREP-A). http://www.jfa.maff.go.jp/j/whale/pdf/newrep--a.pdf. Accessed 06/05/2016. 110 pp.
Hammond PS (1986). Estimating the size of naturally marked whale populations using capture-recapture techniques. Report of the International Whaling Commission (Special Issue) 8: 253-282.
Hammond PS, Mizroch SA, Donovan GP (eds) (1990). Individual recognition of cetaceans: use of photo- identification and other techniques to estimate population parameters. Report of the IWC (Special Issue 12), Cambridge, UK. [vi]+440pp.
Hatch L, Clark C, Merrick R, Van Parijs S, Ponirakis D, Schwehr K, Thompson M, Wiley D (2008). Characterizing the relative contributions of large vessels to total ocean noise fields: A case study using the Gerry E. Studds Stellwagen Bank National Marine Sanctuary. Environment Management 42: 735- 752.
Hauser N, Peckham H, Clapham P (2000). Humpback whales in the Southern Cook Islands, South Pacific. Journal of Cetacean Research and Management 2(3): 159–164.
Hedley SL, Bannister JL, Dunlop RA (2009). Group IV humpback whales: abundance estimates from aerial and land-based surveys off Shark Bay, Western Australia, 2008 Paper submitted for consideration by the IWC Scientific Committee. SC/61/SH23.
Hildebrand JA (2009). Anthropogenic and natural sources of ambient noise in the ocean, Marine Ecology Progress Series 395: 5-20.
Page 211
Hjort J, Lien J, Ruud JT (1932). Norwegian pelagic whaling in the Antarctic. 1. Whaling Grounds in 1929- 1930 and 1930-1931. Hvalradets Skrifter 1-37.
Holyoake C, Stephens N, Coughran D, Bejder L, Warren K (2011). Collection of baseline data on humpback whale (Megaptera novaeangliae) health and causes of mortality for long-term monitoring in Western Australia. In: 48th Annual Conference of the Australian Marine Science Association, 3 - 7 July, Fremantle, Western Australia.
ICJ – International Court of Justice (2014). Whaling in the Antarctic (Australia v. Japan: New Zealand intervening) Summary of the Judgement of 31 March 2014. http://www.icj- cij.org/docket/index.php?p1=3&p2=1&case=148&code=aj&p3=5 Accessed 06/05/2016. 35pp.
IPCC (2007). Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. In: ML Parry, OF Canziani, JP Palutikof, PJ van der Linden, CE Hanson (eds.) Climate Change 2007: Impacts, Adaptation and Vulnerability. Cambridge, UK Cambridge University Press.
IUCN (2012). IUCN Red List Categories and Criteria Version 3.1, Second edition.
IUCN (2014). http://www.iucnredlist.org/details/132832/0 – accessed 16 March 2014.
Ivashchenko Y, Clapham P, Brownell R (2011). Soviet Illegal Whaling: the Devil and the details. Marine Fisheries Review 73(3): 1-19.
Ivashin MV (1973). Marking of whales in the Southern Hemisphere (Soviet Materials). Report to the International Whaling Commission Appendix IV Annex Q: 174-191.
IWC (1998). Report of the Sub-Committee on comprehensive assessment of Southern Hemisphere humpback whales. Report of the Scientific Committee. Annex G. Report of the International Whaling Commission 48:170-182.
IWC (2005). Intersessional Working Group on Southern Hemisphere Humpback Whales. Paper SC/58/Rep 5 presented to the IWC Scientific Committee, June 2005, Ulsan, Korea (Unpublished). 14pp. Available from the Office of the Journal of Cetacean Research and Management.
IWC (2006). Report of the Workshop on the Comprehensive Assessment of Southern Hemisphere Humpback Whales. Paper SC/58/Rep5 presented to the IWC Scientific Committee, June 2006, St Kitts and Nevis, West Indes. 77pp. Available from the Office of the Journal of Cetacean Research and Management.
IWC (2008). Report of the Scientific Committee. Annex H. Report of the sub-committee on other Southern Hemisphere whale stocks. Journal of Cetacean Research and Management (Supplement) 10: 207–224.
IWC (2011). Country report on Ship Strikes. Submitted by the Government of Australia to the Conservation Committee. IWC/63/CC12.
Page 212
Jackson J, Zerbini A, Clapham P, Constantine R, Garrigue C, Hauser N, Poole M, Baker CS (2008). Progress on a two-stock allocation model for reconstructing population histories of east Australia and Oceania. Paper submitted to the Scientific Committee of the International Whaling Commission. SC/60/SH14.
Jackson JA, Steel DJ, Beerli P, Congdon BC, Olavarría C, Leslie MS, Pomilla C, Rosenbaum H, Baker CS (2014). Global diversity and oceanic divergence of humpback whales (Megaptera novaeangliae). Proceedings of the Royal Society B 281(1786): 10pp.
Jackson JA, Zerbini A, Clapham P, Constantine R, Garrigue C, Hauser N, Poole MM, Baker CS (2009). Progress on a two-stock catch allocation model for reconstructing population histories of east Australia and Oceania (Updated from Jackson et al. SC/60/SH14.). Paper to the Scientific Committee of the International Whaling Commission. SC/F09/SH8 13pp.
Jackson JA, Zerbini A, Clapham P, Garrigue C, Hauser N, Poole M, Baker CS (2006). A Bayesian assessment of humpback whales on breeding grounds of eastern Australia and Oceania (IWC Stocks E, E1 E2 and F). Paper SC/A06/HW52 presented to the IWC Workshop on Comprehensive Assessment of Southern Hemisphere Humpback Whales, Hobart, Tasmania, 3–7 April 2006 (unpublished). 19pp. Available from the Office of the Journal of Cetacean Research and Management.
Jurasz CM, Jurasz VP (1979). Feeding modes of the humpback whale Megaptera novaeangliae in southeast Alaska. Scientific Report of the Whales Research Institute 31: 69-83.
Kannan K, Perrotta E, Thomas NJ, Aldous KM (2007). A comparative analysis of polybrominated diphenyl ethers and polychlorinated biphenyls in southern sea otters that died of infectious diseases and noninfectious causes. Archives of Environmental Contamination and Toxicology 53: 293-302.
Katona S (1980). Paper presented at humpback whales of the Western North Atlantic Workshop. New England Aquarium, Boston, Massachusetts.
Katona S, Baxter B, Brazier O, Kraus S, Perkins J, Whitehead H (1979). Identification of Humpback whales by fluke photographs. In: Behaviour of marine animals - current perspectives in research (ed. Winn HEO) 3: pp 33-44 Plenum Press: New York.
Katona SK, Beard JA (1990). Population size, migrations, and feeding aggregations of the humpback whale (Megaptera novaeangliae) in the western North Atlantic Ocean. Report to the International Whaling Commission (Special Issue) 12: 295-306.
Katona SK, Whitehead HP (1981). Identifying humpback whales using their natural markings. Polar Records 20: 439-444.
Kaufman G, Coughran D, Allen J, Burns D, Burton C, Castro C, Constantine R, Childerhouse S, Franklin T, Franklin W, Forestell P, Gales R, Garrigue G, Gibbs N, Jenner C, Paton D, Noad M, Robbins J, Slooten E, Smith F, Stevick P (2011). Photographic evidence of interchange between east Australia (BS E-1) and West Australia (BS D) humpback whale breeding populations. Paper SC/63/SH11. IWC, Tromso, Norway.
Page 213
Kaufman GD, Ward A, Forestell PH (1990). Photographic documentation of the migratory movement of a humpback whale (Megaptera novaeangliae) between east Australia and Antarctic Area V. Report of the International Whaling Commission: 265-267.
Kawaguchi S, Kurihara H, King R, Hale L, Berli T, Robinson JP, Ishida A, Wakita M, Virtue P, Nicol1 S, Ishimatsu A (2011). Will krill fare well under Southern Ocean acidification? Biology Letters 7: 288- 291. doi:10.1098/rsbl.2010.0777.
Kellogg AR (1928). A history of whales – their adaptation to life in water. The Quarterly Review of Biology 3(1): 29-76.
Kellogg AR (1929). What is known of the migrations of some of the whalebone whales. Smithsonian Institute.
Kendall WL, Nichols JD (1995). On the use of secondary capture-recapture samples to estimate temporary emigration and breeding proportions. Journal of Applied Statistics 22: 751-762.
Kendall WL, Nichols JD, Hines, JE (1997). Estimating temporary emigration using capture-recapture data with Pollock’s robust design. Ecology 78: 563-578.
Kendall WL, Pollock KH, Brownie C (1995). A likelihood-based approach to capture-recapture estimation of demographic parameters under the robust design. Biometrics 51: 293-308.
Kniest E, Paton D (2000). Abstracts for the humpback whale conference, Queensland Museum 2000.
Kniest E, Paton D (2001a). Real time tracking of humpback whales. Memoirs of the Queensland Museum 47: 538.
Kniest E, Paton D (2001b). Temporal GIS for marine mammal research. Paper presented at the 14th Biennial Conference on the Biology of Marine Mammals, Vancouver, Canada, 28 November – 3 December 2001.
Lahvis GP, Wells RS, Kuehl DW, Stewart JL, Rhinehart HL, Via CS (1995). Decreased lymphocyte responses in free-ranging bottle-nosed dolphins (Tursiops truncatus) are associated with increased concentrations of PCBs and DDT in peripheral blood. Environmental Health Perspectives 103: 67-72.
Laist DW, Knowlton AR, Mead JG, Collet AS, Podesta M (2001). Collisions between ships and whales. Marine Mammal Science 17: 35-75.
Learmonth JA, MacLeod CD, Santos MB, Pierce GJ, Crick HQP, Robinson RA (2006). Potential effects of climate change on marine mammals. Oceanography and Marine Biology: an Annual Review 44: 431– 464.
Lillie DG (1915). Cetacea. British Antarctic (Terra Nova) Expedition 1910. Natural History Report on Zoology 1: 85-124.
Lockyer C (1976). Body weight of some species of large whales. Journal of Conservation CIEM 36(3): 259- 273.
Page 214
Mackintosh NA (1942). The southern stocks of whalebone whales. Discovery Reports 22: 197-300.
Mackintosh NA (1965). The Stock of Whales. Fishing News 232.
Martin TG, Nally S, Burbidge AA, Arnall S, Garnett ST, Hayward MW, Lumsden LF, Menkhorst P, McDonald-Madden E, Possingham HP (2012). Acting fast helps avoid extinction. Conservation Letters 5: 274-280.
Martineau D, Deguise S, Fournier M, Shugart L, Girard C, Lagace A, Beland P (1994). Pathology and toxicology of beluga whales from the St Lawrence Estuary, Quebec, Canada: Past, present and future. Science of the Total Environment 154: 201-215.
Matthews LH (1937). The humpback whale, Megaptera nodosa. Discovery Reports XVII: 7-92.
McGregor P, Peake T (1998). The role of individual identification in conservation biology. In: Behavioural ecology and conservation biology. (ed. Caro TM). Oxford University Press, New York. pp. 31-55.
Medrano-González L, Aguayo-Lobo A, Urbán-Ramírez J, Baker CS (1995). Diversity and distribution of mitochondrial DNA lineages among humpback whales, Megaptera novaeangliae, in Mexican Pacific Ocean. Canadian Journal of Zoology 73: 1735-1743.
Melcon ML, Cummins AJ, Kerosky SM, Roche LK, Wiggins SM, Hildebrand JA (2012). Blue whales respond to anthropogenic noise. PLOS ONE 7(2).
Mikhalev YA (1997). Humpback whales Megaptera novaeangliae in the Arabian Sea. Marine Ecology Progress Series 149: 13-21.
Mikhalev YA (2000). Biological characteristics of humpbacks taken in Antarctic Area V by the whaling fleets Slava and Sovietskaya Ukraina. Submitted to the Scientific Committee of the IWC. IA12.
Mikhalev YA, Savusin VP, Bushuev SG (2009). Falsification of Soviet whaling data after introduction of the International Observer Scheme. International Whaling Commission, the Red House, Sta. Rd., Impington, Cab., U.K. Pap. SC/61.IA 20, 3p.
Miller PJO, Biassoni N, Samuels A, Tyack PL (2000). Humpback whales sing longer songs when exposed to LFA sonar. Nature 405: 903.
Mizroch SA, Herman LM, Straley JM, Glockner-Ferrari DA, Jurasz C, Darling J, Cerchio S, Gabriele CM, Salden DR, von Ziegesar O (2004). Estimating the adult survival rate of central North Pacific humpback whales (Megaptera novaeangliae). Journal Of Mammalogy 85(5): 963-972.
Nicol S, Worby A, Leaper R (2008). Changes in the Antarctic sea ice ecosystem: potential effects on krill and baleen whales. Marine Freshwater Research 59: 361−382.
Nishiwaki M (1959). Humpback whales in Ryukyuan waters. Scientific Reports of the Whales Research Institute, Tokyo 14: 49-87.
Page 215
Noad M, Cato DH, Paton D (2006). Absolute and relative abundance estimates of Australian east coast humpback whales. Paper submitted to the Scientific Committee of the International Whaling Commission. SC/A06/HW27.
Noad M, Dunlop R, Paton D, Kniest H (2011c). Abundance estimates of the east Australian Humpback whale population 2010 survey. Final Report for the Australian Marine Mammal Centre, Australian Antarctic Division. 19 April 2011.
Noad MJ, Cato DH, Bryden MM, Jenner MN, Jenner KCS (2000). Cultural revolution in whale songs. Nature 408: 537.Noad MJ, Dunlop RA (2007). Abundance estimates of the east Australian humpback whale population. Progress report for the Australian Department of the Environment and Water Resources (unpublished). Report available from Australian Department of the Environment and Water, Arts and Heritage, GPO Box 787 Canberra, 2601 ACT Australia.
Noad MJ, Dunlop RA, Paton D, Cato DH (2008). An update of the east Australian humpback whale population (E1) rate of increase. Paper SC/60/SH31 presented to the IWC Scientific Committee, June 2008, Santiago, Chile (unpublished). 13pp. Available from the Office of the Journal of Cetacean Research and Management.
Noad MJ, Dunlop RA, Paton D, Cato DH (2011b). Absolute and relative abundance estimates of Australian east coast humpback whales (Megaptera novaeangliae). Journal of Cetacean Research and Management (Special Issue) 3: 243-252.
Noad MJ, Dunlop RA, Paton D, Kniest E (2011a). Abundance estimates of the east Australian humpback whale population: 2010 survey and update. Paper submitted to the IWC Scientific Committee, Tromsø, Norway, 30 May - 11 June. SC/63/SH22.
Noad MJ, Paton DA, Cato DH, Dunlop RA, Kniest E, Wyn Morris C (2007). Survey of east Australia humpback whales (Megaptera novaeangliae) from Point Lookout, 2004. Unpublished report to the Department of the Environment and Heritage, Canberra, Australia. Report available from Australian Department of the Environment and Water, Arts and Heritage, GPO Box 787 Canberra, 2601 ACT Australia.
Nowacek DP, Thorne LH, Johnston DW, Tyack PL (2007). Responses of cetaceans to anthropogenic noise. Mammalian Review 37(2): 81-115.
Olavarría C, Anderson M, Paton DA, Burns D, Brasseur M, Garrigue C, Hauser N, Poole M, Caballero S, Flórez-Gonzalez L, Baker CS (2006). Eastern Australian humpback whale genetic diversity and their relationship with Breeding Stocks D, E, F and G. Paper SC/58/SH25 presented to the IWC Scientific Committee, May 2006, St Kitts and Nevis, West Indies (unpublished). 6pp. Available from the Office of the Journal of Cetacean Research and Management.
Omura H, Kawakami T (1956). Japanese whale marking in the North Pacific. The Norwegian Whaling Gazette Volume 10: 555-563.
Page 216
Oosterman A, Whicker M (2013). Norfolk Island Whale Survey 2012. (unpublished). Available from PO Box 143 Scarborough, Qld 4020 Australia. 19pp.
Otis DL, Burnham KP, White GC, Anderson DR (1978). Statistical inference from capture data on closed animal populations. Wildlife Monographs 62: 1-135.
Ouellet J, Heard D, Mulders R (1994). Population Ecology of Caribou Populations without Predators: Southampton and Coast Island Herds. Rangifer (Special Issues) No 9: 17--26.
Palsbøll PJ, Clapham PJ, Mattila DK, Larsen F, Sears R, Siegismund HR, Sigurjonsson J, Vasquez O, Arctander P (1995). Distribution of mtDNA haplotypes in North Atlantic humpback whales: the influence of behaviour on population structure. Marine Ecology Progress Series 116: 1-10.
Paterson R (1980). Encouraging sightings of humpback whales off east coast. Australian Fisheries, April 1980: 8-10.
Paterson R (1984) Migration patterns of humpback whales (Megaptera novaeangliae) in the waters adjacent to Moreton and North Stradbroke Islands. In Focus on Stradbroke (eds Coleman RJ, Covacewich J, Davie P) pp. 342-347, Boolarong Publications: Brisbane.
Paterson R (1985). Sightings suggest whale numbers increasing. Australian Fisheries, May 1985: 43-45.
Paterson R (1986). Optimistic outlook for east coast humpback whale stock. Australian Fisheries, April 1986: 25-28.
Paterson R (1987). Recovery in the east Australian humpback whale stock. Australian Fisheries, August 1987: 32-36.
Paterson R, Paterson P (1984). A study of the past and present status of humpback whales in east Australian waters. Biological Conservation 29: 321-343.
Paterson R, Paterson P (1989). The status of the recovering stock of humpback whales Megaptera novaeangliae in east Australian waters. Biological Conservation 47: 33-48.
Paterson R, Paterson P, Cato DH (1994). The status of humpback whales Megaptera novaeangliae in east Australia thirty years after whaling. Biological Conservation 70: 135-142.
Paterson R, Paterson P, Cato DH (2001). Status of humpback whales, Megaptera novaeangliae, in east Australia at the end of the 20th Century. Memoirs of the Queensland Museum 47(2): 579-586.
Paterson R, Paterson P, Cato DH (2004). Continued increase in east Australian humpback whales in 2001, 2002. Memoirs of the Queensland Museum 49(2):712.
Paterson RA (1991). The migration of humpback whales Megaptera novaeangliae in east Australian waters. Memoirs of the Queensland Museum 30(2): 333-341.
Page 217
Paterson RA (2001). Exploitation of humpback whales, Megaptera novaeangliae, in the South West Pacific and adjacent Antarctic waters during the 19th and 20th Centuries. Memoirs of the Queensland Museum 47(2): 421-429.
Paton D (2005). Summary of humpback whale entanglement rates for eastern Australia, 1997-2004. Report for the Department of Environment and Heritage, Canberra, Australia.
Paton D, Brooks L, Burns D, Kniest E, Harrison P, Baverstock P (2009). Abundance estimate of Australian East Coast humpback whales (Group E1) in 2005 using multi-year photo-identification data and capture-recapture analysis, Unpublished IWC paper SC/61/SH10.
Paton D, Clapham P (2002). Preliminary analysis of humpback whale sighting survey data collected in Fiji, 1956-1958. IWC Scientific Committee: SC/54/H7.
Paton DA, Brooks L, Burns D, Franklin T, Franklin W, Harrison P. Baverstock P (2011). Abundance of East Coast Australian humpback whales (Megaptera novaeangliae) in 2005 estimated using multi-point sampling and capture-recapture analysis. Journal of Cetacean Research and Management (Special Issue) 3: 253-259.
Paton DA, Brooks L, Burns D, Kniest E, Harrison P, Baverstock P (2009). Abundance estimate of Australian East Coast humpback whales (Group E1) in 2005 using multi-year photo-identification data and capture-recapture analysis. Report SC/A06/HW33 submitted to the Scientific Committee of the IWC. 11pp.
Paton DA, Clapham PJ (2006). An assessment of Southern Hemisphere humpback whale population structure and migratory interchange based on Discovery mark data. Paper SC/A06/HW33 presented to the IWC Workshop on Comprehensive Assessment of Southern Hemisphere Humpback Whales, Hobart, Tasmania, 3-7 April 2006 (unpublished). 19pp. Available from the Office of the Journal of Cetacean Research and Management.
Paton DA, Kniest E (2011). Population growth of Australian East Coast humpback whales, observed from Cape Byron, 1998 to 2004. Journal of Cetacean Research and Management (Special Issue) 3: 261-268.
Paton DA, Oosterman A, Whicker M, Kenny I (2006). Preliminary assessment of sighting data of humpback whales, Norfolk Island, Australia. Unpublished paper SC/A06/HW36 presented the IWC Scientific Committee. Available from the Office of the Journal of Cetacean Research and Management.
Paton DA, Oosterman A, Whicker M, Kenny I Christian M, Garrigue C (In review) Assessment of sighting survey data for humpback whales (Megaptera novaeangliae) at Norfolk Island 2003-2006 and a comparison with historical records for the region. Submitted to Journal of Cetacean Research and Management.
Payne, K, Payne R (1985). Large Scale Changes over 19 Years in Song of Humpback Whales in Bermuda. Zeitschrift fur Tierpsychologie 68: 89-114.
Page 218
Peel D, Kelly N, Smith J, Childerhouse S (2015). Quantitative assessment of the risk of ship strike to humpback whales in the Great Barrier Reef. Final Report to the Australian Marine Mammal Centre Grants Programme (Project 13/46), Australian Antarctic Division, Australia.
Pickering A, Cowley S (2010). Risk Matrices: implied accuracy and false assumptions. Journal of Health and Safety Research and Practice 2(10): 9-16.
Pinheiro JC, Bates DM (2000). Mixed effects models in S and S-PLUS. Springer-Verlag, New York.
Popper AN, Hawkins AD (eds) (2012). The effects of noise on aquatic life. New York: Springer Science + Business Media, LLC.
Polanowski AM, Robbins J, Chandler D, Jarman SN (2014). Epigenetic estimation of age in humpback whales. Molecular Ecology Resources 14(5): 976-987.
Punt AE, Wade PR (2010). Population status of the eastern North Pacific stock of gray whales in 2009. U.S. Dep. Commer., NOAA Tech. Memo. NMFS-AFSC-207, 43pp.
R Development Core Team (2006). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, URL: http://www.R-project.org.
Rasmussen K, Calambokidis J, Steiger G, Saborio M, May L, Gerrodette T (2001). Extent of geographic overlap of North Pacific and South Pacific humpback whales on their Central American wintering grounds. (Abstract). In Proceedings of the 14th biennial Conference on the Biology of Marine Mammals. Vancouver, BC p. 175.
Rayner GW (1940). Whale marking progress and results to December 1939. Discovery Report 19: 245-284.
Read AJ (2009). Telemetry. In: Encyclopaedia of Marine Mammals 2nd Edition. (eds) WF Perrin, B Wursig, JGM. Thewissen. pp. 624-628. Elseriver, Canada.
Rekdahl M (2012). Humpback whale vocal communication: Use and stability of social calls and revolutions in the songs of east Australian whales. PhD thesis, the University of Queensland, 191pp.
Rexstad EA, Burnham KP (1992). User’s Guide for Interactive Program CAPTURE. Colorado Coop. Fish and Wildl. Res. Unit, Colorado State University, Fort Collins. 29pp.
Rice DW (1998). Marine mammals of the world: systematics and distribution. The Society for Marine Mammalogy: Lawrence, KS.
Rice M, Carlson C, Chu K, Dolphin W, Whitehead H (1987). Are humpback whale population estimates being biased by sexual differences in fluking behavior? Report of the International Whaling Commission 37: 333-335.
Richardson WJ, Greene CRJ, Malme CI, Thomson DH (1995). Marine Mammals and Noise. Academic Press, New York, NY.
Page 219
Robbins J, Landry S, Mattila D (2009). Estimating entanglement mortality from scar-based studies. Paper SC/61/BC3 presented to the IWC Scientific Committee.
Robbins J, Rosa DL, Allen J, Mattila D, Secchi E, Friedlaender A, Stevick P, Nowacek D, Steel D (2011). Return movement of a humpback whale between the Antarctic Peninsula and American Samoa: a seasonal migration record. Endangered Species Research 13: 117-121.
Rock J, Pastene LA, Kaufman GD, Forestell P, Matsuoka K, Allen J (2006). A note on East Australia Group V Stock humpback whale movement between feeding and breeding areas based on photo-identification. Journal of Cetacean Research and Management 8: 301-305.
Rolland RM, Parks SE, Hunt KE, Castellote M, Corkeron PJ, Nowacek NP, Wasser SK, Kraus SD (2012) Evidence that ship noise increases stress in right whales. Proc. R. Soc. B doi:10.1098/rspb.2011.2429
Ruud JT, Oynes P (1954). International co-operation in whale marking: the second period of the voyage of the Enern to the Ant-arctic 1953, and the trials with whale marks conducted on board floating factories in the season 1954. Norsk Hvalfangsttidende Sandefjord 43: 383-393.
Salgado Kent C, McCauley RD, Duncan AJ, Jenner C, Holley D (2009). Environmental impacts of underwater noise associated with harbor works, Port Hedland, report 2008-50.1. Centre for Marine Science and Technology, Curtin University.
Schaffar A, Madon B, Garrigue C, Constantine R (2009). Avoidance of whale watching boats by humpback whales in their main breeding ground in New Caledonia SC/61/WW6, IWC pp. 9.
Schmitt NT, Double MC, Jarman SN, Gales N, Marthick JR, Polanowski A, Baker CS, Steel D, Jenner KCS, Jenner M-N, Gales R, Paton D, Peakall R (2014). Low levels of genetic differentiation characterize Australian humpback whale (Megaptera novaeangliae) populations. Marine Mammal Science 30(1): 221-241.
Schwarz CJ (2005). Multistate models. In SC Amstrup, TL McDonald, BFJ Manly (eds) Handbook of Capture- Recapture Analysis. Princeton University Press, NJ.
SEWPAC (2011). Whale watching in Commonwealth Waters: Review of management arrangements. Australian Government report pp. 16.
Silber KG, Bettridge S (2012). An assessment of the final rule to implement vessel speed restrictions to reduce the threat of vessel collisions with North Atlantic Right Whales. NOAA Technical Memorandum NMFS-OPR-48. February 2012.
Smith JN, Goldizen AW, Dunlop RA, Noad MJ (2008). Songs of male humpback whales, Megaptera novaeangliae, are involved in intersexual interactions. Animal Behaviour 76: 467-477.
Smith JN, Grantham HS, Gales N, Double MC, Noad MJ, Paton D (2012). Identification of humpback whale breeding and calving habitat in the Great Barrier Reef. Marine Ecology Progress Series 447: 259-272.
Page 220
Smith TD, Allen J, Clapham PJ, Hammond PS, Katona S, Larsen F, Lien J, Mattila D, Palsbøll PJ, Sigurjónsson J, Stevick PT, Øien, N (1999). An ocean-basin-wide mark-recapture study of the North Atlantic humpback whale (Megaptera novaeangliae). Marine Mammal Science 15(1): 1--32.
Smith TD, Reeves RR, (2003). Estimating American 19th Century Catches of Humpback Whales in the West Indies and Cape Verde Islands. Caribbean Journal of Science, 39(3): 286-297.
Sormo EG, Larsen HJS, Johansen GM, Skaare JU, Jenssen BM (2009). Immunotoxicity of polychlorinated biphenyls (PCB) in free-ranging gray seal pups with special emphasis on dioxin-like congeners. Journal of Toxicology and Environmental Health 72: 266-276.
Southall BL, Bowles AE, Ellison WT, Finneran JJ, Gentry RL, Greene Jr CR, Kastak D, Ketten DR, Miller JH, Nachtigall PE, Richardson WJ, Thomas JA, Tyack PL (2007). Marine mammal noise exposure criteria: Initial scientific recommendations. Aquatic Mammals 33: 411-521.
SPREP - Secretariat of the Pacific Regional Environment Programme (2011). The Oceania humpback whales recovery plan. SPREP document number 22SM/WP.8.1.2/Att1. Available at www.sprep.org. 47pp.
SPWRC (2008). Annual Report of the South Pacific Whale Research Consortium to the IWC.
Stamation KA, Croft DB, Shaughnessy PD, Waples KA (2007). Observations of humpback whales (Megaptera novaeangliae) feeding during their southward migration along the coast of southeastern New South Wales, Australia: identification of a possible supplemental feeding ground. Aquatic Mammals 33: 165- 174.
Steel D, Anderson M, Schmitt N, Burns D, Constantine R, Franklin W, Franklin T, Garrigue C, Gibbs N, Hauser N, Olavarría C, Paton D, Poole M, Robbins J, Ward J, Double M, Harrison P, Baverstock P, Baker CS (2011). Genotype matching of humpback whales from the 2010 Australia/New Zealand Antarctic Whale Expedition (Area V) to the South Pacific. Paper SC/63/SH10 presented to the IWC Scientific Committee, 2011.
Steel D, Garrigue C, Poole M, Hauser N, Olavarría C, Flórez-González L, Constantine R, Caballero S, Thiele D, Paton D, Clapham P, Donoghue M, Baker CS (2008). Migratory connections between humpback whales from South Pacific breeding grounds and Antarctic feeding areas demonstrated by genotype. Paper SC/60/SH13 presented to the Scientific Committee of the IWC.
Steiger GH, Calambokidis J, Sears R (1991). Movement of humpback whales between California and Costa Rica. Marine Mammal Science 7: 306-310.
Stevick PT (2005). Stock identity of humpback whales near the Antarctic Peninsula: evidence from movement of naturally marked individuals. Paper SC/57/SH2 presented to the IWC Scientific Committee.
Tomlin AG (1967). Cetacea. Mammals of the U.S.S.R. and Adjacent Countries. Vol. 9. Israel Program for Scientific Translation, Jerusalem. 71 7pp.
Townsend CH (1935). The distribution of certain whales as shown by log book records of American whaleships. Zoologica 19: 1-50.
Page 221
True FW (1904). The whalebone whales of the western North Atlantic compared with those occurring in European waters: with some observations on the species of the North Pacific. Smithsonian Contributions to Knowledge 33: 1-318.
Taylor BL, Chivers SJ, Larese J, Perrin WF (2007). Generation length and percent mature estimates for IUCN assessments of cetaceans. NOAA Administrative Report LJ-07-01. National Marine Fisheries Service, Southwest Fisheries Science Center. 24pp.
UNEP – United Nations Environment Programme (2009). Marine Litter: A Global Challenge. Published UNEP http://www.unep.org/pdf/UNEP_Marine_Litter-A_Global_Challenge.pdf.
Urbán J, Alvarez FC, Salinas ZM, Jacobsen J, Balcomb KC, Jaramillo LA, Ladrón de Guevara PP, Aguayo LA (1999). Population size of the humpback whale, Megaptera novaeangliae, in waters off the Pacific coast of Mexico. Fisheries Bulletin 97: 1107-1024.
Valsecchi E, Corkeron P, Galli P, Sherwin W, Bertorelle G (2010). Genetic evidence for sex-specific migratory behaviour in western South Pacific humpback whales. Marine Ecological Progress Series 398: 275- 286.
Valsecchi E, Palsbøll P, Hale P, Glockner-Ferrari D, Ferrari M, Clapham P, Larsen F, Mattila D, Sears R, Sigurjonsson J, Brown M, Corkeron P, Amos B (1997). Microsatellite genetic distances between oceanic populations of the humpback whale (Megaptera novaeangliae). Molecular Biology and Evolution 14(4): 355-362.
Van Bressem MF, Van Waerebeek K, Raga JA (1999). A review of virus infections of cetaceans and the potential impact of morbilliviruses, poxviruses, and papillomaviruses on host population dynamics. Diseases of Aquatic Organisms 38: 53-65.
Vanderlaan ASM, Taggart CT (2007). Vessel collisions with whales: the probability of lethal injury based on vessel speed. Marine Mammal Science 23: 144-156.
WADSD (Western Australian Government Department of State Development) (2010). Browse LNG precinct strategic assessment report (SAR), Perth, viewed 20 May 2011,
Waugh CA, Schlabach M, Noad M, Bengtson Nash SM (2012). The effect of migration and fasting on organochlorine contaminants burdens in southern hemisphere humpback whales. Organohalogen compounds 74: 919-922.
Williams BK, Nichols JD, Conroy MJ (2002). Analysis and Management of Animal Populations. Academic Press, San Diego, CA. 815pp.
Winn HE, Reichley NE (1985). Humpback whale – Megaptera novaeangliae (Borowski, 1781). In: Handbook of Marine Mammals. Vol. 3. The sirenians and Baleen Whales (ed. SH Ridgway, R Harrison) pp. 241- 73 Academic Press: London and Orlando.
Wright AJ, Soto NA, Baldwin AL, Bateson M, Beale CM, Clark C, Deak T, Edwards EF, Fernández A, Godinho A, Hatch LT, Kakuschke A, Lusseau D, Martineau D, Weilgart LS, Wintle BA, Notarbartolo-
Page 222
di-Sciara G, Martin V (2007). Do marine mammals experience stress related to anthropogenic noise? International Journal of Comparative Psychology, 20: 274-316.
WWF (2010). Collision course: snubfin dolphin injuries in Roebuck Bay. Report prepared by Dr Deborah Thiele for WWF-Australia.
Yablokov AV (1994). Validity of whaling data. Nature 367: 108.
Zhang Z, Cato D, Exelby JR (2004). Australian Defence Science and Technology Organisation 12(1).
Zerbini AN, Clapham PJ, Wade PR (2010). Assessing plausible rates of population growth in humpback whales from life-history data. Marine Biology 157(6): 1225-1236.
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APPENDICES
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APPENDIX I: PUBLISHED PAPER – POPULATION GROWTH OF AUSTRALIAN EAST COAST HUMPBACK WHALES, OBSERVED FROM CAPE BYRON, 1998 TO 2004
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APPENDIX II: GROWTH RATE MODEL IN 10- HOUR SIGHTING RATES IN BYRON BAY 1998-2004
The data analysed were:
Year Rate ln(rate) 1 25.471 3.238 2 23.375 3.152 3 20.518 3.021 4 32.331 3.476 5 32.357 3.477 6 32.118 3.469 7 47.020 3.851
A growth model was fitted by generalised least squares (REML)10 according to the function:
푙푛(푟푎푡푒)푡𝑖푚푒 = 훽0 + 훽1 × 푡𝑖푚푒 + 휀푡𝑖푚푒
In terms of rate:
훽0 훽1 × 푡푖푚푒 휀푡푖푚푒 푟푎푡푒푡𝑖푚푒 = 푒 × 푒 × 푒
The parameter estimates on the log scale with 95% confidence intervals were:
훽0 = [2.598 < 2.965 < 3.332];
훽1 = [0.022 < 0.105 < 0.187]
The growth parameter on the rate scale with 95% confidence interval was (by back- transformation):
10 Using function GLS in package nlme (Pinheiro and Bates, 2000) in program R (R Development Core Team, 2006).
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푒훽1 = [1.02 < 1.11 < 1.21]; i.e. the estimated growth rate with 95% confidence interval was 2.3% < 11.0% < 20.5%.
This cannot be correctly stated as mean ± 95%CI because the interval was not symmetric about the estimate.
RSQ for the model was 0.683.
A plot of the autocorrelation function (ACF) on the residuals indicated little serial correlation structure and a second model which fitted an AR1 structure was found not to be a significantly better fit than the original model by the likelihood ratio test (p = 0.994). The estimate of the AR1 parameter with 95% confidence interval was:
푝ℎ𝑖(퐴푅1) = [−0.864 < 0.006 < 0.868]
The estimated growth rate with 95% confidence interval from the AR1 model was
2.3% < 11.0% < 20.5%.
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APPENDIX III: PUBLISHED PAPER – ABUNDANCE OF EAST COAST AUSTRALIAN HUMPBACK WHALES (MEGAPTERA NOVAEANGLIAE) IN 2005 ESTIMATED MULTI-POINT SAMPLING AND CAPTURE- RECAPTURE ANALYSIS
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APPENDIX IV PUBLISHED AND UNPUBLISHED DOCUMENTS CONTAINING DISCOVERY MARK DATA AND/OR ANALYSES
Number Reference 1 Anon 1952. Whale marks recently recovered. The Norwegian Whaling Gazette Volume 8 pages 433. 2 Anon 1953. Whale marks recently recovered. The Norwegian Whaling Gazette Volume 9 pages 487. 3 Anon (date unknown). Report of the Scientific Committee, Annex G Appendix 5 Humpback mark Recoveries particularly from Areas I, II, III and VI. 4 Brown SG (1956). Whale Marks Recently Recovered. The Norwegian Whaling Gazette Volume 12 pages 661-664. 5 Brown SG (1959). Whale Marks Recovered during the Antarctic Whaling Season 1956/57 The Norwegian Whaling Gazette pages 555- 595. 6 Brown SG (1971). Whale marking – progress report, 1970 IWC Scientific report to the commission PP 51-55. 7 Brown SG (1977). Whale Marking - Progress Report 1976 Rep. Int. Whal. Commn 27 (SC/28/Rep 10) Pages 64-66. 8 Chapman D (1972) Catch and effort data together with further analysis of marking data for Antarctic baleen whale stocks. IWC Report Annex G pages 54-59. 9 Chittleborough RG (1959). Australian Marking of Humpback Whales The Norwegian Whaling Gazette Volume 48 pages 47-55. 10 Chittleborough RG, Godfrey K (1957). A review of whale marking and some trials of a modified whale mark. The Norwegian Whaling Gazette Volume 46 pages 238-248. 11 Clark R (undated). The possibility of injuring small whales with the standard Discovery whale Mark (SC/22/17).
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Number Reference 12 Clarke R (1962). Whale observation and whale marking off the coast of Chile in 1958 and from Ecuador toward and beyond the Galapagos Islands in 1959. The Norwegian Whaling Gazette Volume 7 pages 265-287. 13 Clarke R, Ruud JT (1954). International co-operation in whale marking: The voyage of the Enern to the Antarctic 1953. The Norwegian Whaling Gazette Volume 3 pages 128-146. 14 Dawbin WH (1956). Whale marking in South Pacific waters The Norwegian Whaling Gazette Volume 9 pages 213-238. 15 Dawbin WH (1959). Report on whale marking in New Zealand and south The Norwegian Whaling Gazette Volume 5 pages 429-441. 16 Dawbin WH (1964). Movements of humpback whales marked in the south west Pacific Ocean 1952 to 1962 The Norwegian Whaling Gazette Volume 3 pages 68-78. 17 Dawbin WH (undated). Original Discovery marking logbooks compiled by Dr William Dawbin for marking activities he coordinated in Australia, New Zealand and the Oceania region. These logbooks form part of the Dawbin collection of material now held by the Mitchell Library in Sydney. 18 Ivashin MV (1973). Marking of whales in the southern Hemisphere (Soviet Materials) Report to the International Whaling Commission. Appendix IV Annex Q. 19 Ivashin MV (1962). Marking humpback whale in the south Hemisphere. Zoologichexky Zhurnal, vol XLI, No 12 pages 1848-1858. 20 Ivashin MV (1971). Some results of whale marking carried out from Soviet ships in the South Hemisphere, Zoologichesky zhurnal, vol. L. No 7, pages 1063-1078. 21 Ivashin MV, Rovnin AA (1967). Some results of the Soviet Whale marking in the Waters of the North Pacific. The Norwegian Whaling Gazette Volume 6 pages 1223-135. 22 Mackintosh NA (1952). The marking of whales. The Norwegian Whaling Gazette Volume 5 pages 236-240. 23 Mackintosh NA (1955). Whale marks recently recovered. The Norwegian Whaling Gazette Volume 1 pages 24-26.
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Number Reference 24 Mikhalev et al. (1997). SC/48/SH29 REP. INT. COMMN 47 25 Omura H, Kawakami T (1956). Japanese whale marking in the North Pacific. The Norwegian Whaling Gazette Volume 10 pages 555-563 26 Rayner GW (1940). Whale marking. Progress and result to December 1939. Discovery Reports XIX pages 245-284. 27 Rayner GW (1948). Whale marking II. Distribution of blue, fin and humpback whales marked from 1932 to 1938. Discovery Reports XXV pages 31- 38. Progress and result to December 1939. Discovery Reports XIX pages 245-284. 28 Ravninger R (1955). Report on the whale marking voyage of the Enern to the Antarctic 1954. The Norwegian Whaling Gazette Volume 6 pages 310-315. 29 Rudd J, Oynes P (1954). Trials with whale marks conducted on board floating factories in the season 1954 The Norwegian Whaling Gazette Volume 7 pages 383-393. 30 Ruud Jt, Clarke R, Jonsgard A (1953). Whale marking trials at Steinshamn, Norway. The Norwegian Whaling Gazette Volume 8 pages 429-441. 31 Ruud JT, Oynes P (1957). Report on whale marking carried out by Norwegian catchers in the Antarctic season 1955-56. The Norwegian Whaling Gazette Volume 2 pages 59-63. 32 Ruud JT, Oynes P (1959). Whale marking carried out by Norwegian catchers in the Antarctic, seasons 1956-57 and 1957-58. The Norwegian Whaling Gazette Volume 2 pages 56-62.
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