Project A5 - Exploring the status of Australia’s hammerhead sharks Project Leader: Michelle Heupel AIMS (William White CSIRO, Andrew Chin & Colin Simpfendorfer, JCU) Research Plan 1 - 2015 Progress report to 30 December 2015 Enquiries should be addressed to: Michelle Heupel, Australian Institute of Marine Science [email protected] Distribution list Nic Bax Annabel Ozimec Copyright This report is licensed by the University of Tasmania for use under a Creative Commons Attribution 4.0 Australia Licence. For licence conditions, see https://creativecommons.org/licenses/by/4.0/ Acknowledgement This work was undertaken for the Marine Biodiversity Hub, a collaborative partnership supported through funding from the Australian Government’s National Environmental Research Program (NESP). NESP Marine Biodiversity Hub partners include the University of Tasmania; CSIRO, Geoscience Australia, Australian Institute of Marine Science, Museum Victoria, Charles Darwin University, the University of Western Australia, Integrated Marine Observing System, NSW Office of Environment and Heritage, NSW Department of Primary Industries. Important Disclaimer The NESP Marine Biodiversity Hub advises that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, the NESP Marine Biodiversity Hub (including its host organisation, employees, partners and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it. Contents PROJECT SUMMARY ................................................................................................. 1 1. Background ....................................................................................................... 1 2. Aims ................................................................................................................... 2 3. Approach ........................................................................................................... 2 4. Results ............................................................................................................... 3 Fisheries review............................................................................ 3 5. Identification issues .......................................................................................... 7 6. Life history ......................................................................................................... 9 7. Distribution ...................................................................................................... 10 Scalloped and Great Hammerheads ........................................... 10 8. Regional Distributions .................................................................................... 11 Western Australia ....................................................................... 11 Northern Territory ....................................................................... 18 Queensland ................................................................................ 18 Papua New Guinea .................................................................... 25 Indonesia .................................................................................... 25 9. Other data ........................................................................................................ 29 Winghead sharks ........................................................................ 30 10. Stock structure hypotheses for scalloped hammerheads ........................... 36 11. Conclusions ..................................................................................................... 40 ACKNOWLEDGEMENTS .......................................................................................... 42 REFERENCES ........................................................................................................... 43 List of Figures Figure 1. Fishery catch of S. lewini, S. mokarran, and S. zygaena (from top to bottom) extracted from Koopman and Knuckey (2014). Fishery abbreviations: ECIFF = East Coast Inshore Finfish Fishery (Qld), ONLF = Offshore Net and Line Fishery (NT), NSF = Northern Shark Fishery (WA), ETBF = Eastern Tuna and Billfish Fishery (Commonwealth), GoCIFF = Gulf of Carpentaria Inshore Finfish Fishery (Qld), TDGDLF = Temperate Demersal Gillnet and Demersal Longline Fishery (WA), SESSF = Southern and Eastern Scalefish and Shark Fishery (Commonwealth), MSF = Marine Scalefish Fishery (SA). ................................................................................... 5 Figure 2. Ten year time series of shark catch (CPUE) from northwestern Australia, extracted from Heupel and McAuley (2007). Hammerhead catch is shown in panel b. ............... 6 Figure 3. Total catch of CITES listed sharks in Australia indicating S. lewini (scalloped hammerhead) has the largest take. Extracted from Koopman and Knuckey (2014). ... 6 Figure 4. Images of scalloped (S. lewini), great (S. mokarran) and winghead (E. blochii) after fishery capture from top to bottom. Images supplied by W. White. ............................... 8 Figure 5. Dorsal fins from three hammerhead shark species after removal by fishers. Note the similarities in height and fin shape which distinguish these species from other sharks, but make species identification within the group difficult. Images provided by W. White. ............................................................................................................................. 8 Figure 6. Location data used to define the distribution of hammerhead sharks for: a) S. lewini and b) S. mokarran. Map data ©2015 Google ............................................................ 12 Figure 7. Distribution of: a-c) scalloped hammerhed (S. lewini) and d-f) great hammerhed sharks (S. mokarran) for the different sex and size categories: a, d) adult females, b, e) adult males, c, f) immature and neonate individuals of both sexes. Map data ©2015 Google ......................................................................................................................... 13 Figure 8. Size frequency a) S. lewini and b) S. mokarran in Australian waters by sex. Dashed lines represent corresponding size at maturity for each sex and species. .................. 14 Figure 9. Distribution of scalloped hammerhed sharks (S. lewini) in Western Australia where green indicates adult females, blue indicates adult males, yellow and pink indicate immature and neonate individuals of both sexes respectively. Map data ©2015 Google ......................................................................................................................... 15 Figure 10. Distribution of great hammerhed sharks (S. mokarran) in Western Australia where green indicates adult females, blue indicates adult males, yellow indicates immature individuals of both sexes. Map data ©2015 Google .................................................... 16 Figure 11. Size frequency of individuals encountered in Western Australia by sex for a) S. lewini and b) S. mokarran. Dashed lines represent corresponding size at maturity for each sex and species. ................................................................................................. 17 Figure 12. Distribution of scalloped hammerhed sharks (S. lewini) in Northtern Territory where green indicates adult females, blue indicates adult males, yellow and pink indicate immature and neonate individuals of both sexes. Map data ©2015 Google ............... 19 Figure 13. Distribution of great hammerhed sharks (S. mokarran) in Northern Territory where green indicates adult females, blue indicates adult males, yellow indicates immature individuals of both sexes. Map data ©2015 Google ................................................... 20 Figure 14. Size frequency of individuals encountered in Northern Territory by sex for a) S. lewini and b) S. mokarran. Dashed lines represent corresponding size at maturity for each sex and species. ................................................................................................. 21 Figure 15. Distribution of scalloped hammerhed sharks (S. lewini) in Queensland where blue indicates adult males, yellow and pink indicate immature and neonate individuals of both sexes. Note no adult females were present in the data set. Map data ©2015 Google ......................................................................................................................... 22 Figure 16. Distribution of great hammerhed sharks (S. mokarran) in Queensland where green indicates adult females, blue indicates adult males, yellow indicates immature individuals of both sexes. Map data ©2015 Google .................................................... 23 Figure 17. Size frequency of individuals encountered in Queensland by sex for a) S. lewini and b) S. mokarran. Dashed lines represent corresponding size at maturity for each sex and species. ................................................................................................................. 24 Figure 18. Distribution