Tasmanian Octopus Fishery Assessment 2014/15

Total Page:16

File Type:pdf, Size:1020Kb

Tasmanian Octopus Fishery Assessment 2014/15 TASMANIAN OCTOPUS FISHERY ASSESSMENT 2014/15 Timothy Emery and Klaas Hartmann February 2016 TASMANIAN OCTOPUS FISHERY ASSESSMENT 2014/15 Timothy Emery and Klaas Hartmann February 2016 This assessment of the Tasmanian Octopus Fishery is produced by the Institute for Marine and Antarctic Studies (IMAS). ISBN: 9781862958142 IMAS Fisheries Aquaculture and Coasts Private Bag 49 Hobart TAS 7001 Australia Email timothy.emery@utas.edu.au Ph: 03 6227 7284, +61 3 6227 7284 (international) Fax: 03 6227 8035 The authors do not warrant that the information in this document is free from errors or omissions. The authors do not accept any form of liability, be it contractual, tortious, or otherwise, for the contents of this document or for any consequences arising from its use or any reliance placed upon it. The information, opinions and advice contained in this document may not relate, or be relevant, to a reader’s particular circumstance. Opinions expressed by the authors are the individual opinions expressed by those persons and are not necessarily those of the Institute for Marine and Antarctic Studies (IMAS) or the University of Tasmania (UTAS). © Institute for Marine and Antarctic Studies, University of Tasmania 2016 Copyright protects this publication. Except for purposes permitted by the Copyright Act, reproduction by whatever means is prohibited without the prior written permission of the Institute for Marine and Antarctic Studies. Contents Executive Summary ................................................................................ 5 1. Introduction ...................................................................................... 7 The fishery ................................................................................................................. 7 Assessment of stock status ................................................................................... 10 Stock status definitions ................................................................................................. 10 Proposed performance indicators and reference points............................................. 10 Data sources and analysis ..................................................................................... 11 Commercial data ............................................................................................................ 11 Recreational fishery ....................................................................................................... 11 Data analysis .................................................................................................................. 11 Species biological summaries ...................................................................................... 12 2. State catch, effort and catch rates ................................................ 15 Commercial catch from octopus pots ................................................................... 15 Influence of soak time .................................................................................................... 15 Catch and effort .............................................................................................................. 15 CPUE ............................................................................................................................... 17 Commercial catch from other fishing methods .................................................... 19 Recreational catch .................................................................................................. 20 3. Fine-scale catch, effort and catch rates ....................................... 21 4. Stock status ................................................................................... 24 5. Bycatch and protected species interaction ................................. 25 Acknowledgements ............................................................................... 26 References ............................................................................................. 26 IMAS Fishery Assessment Report Page 4 Executive Summary STOCK STATUS TRANSITIONAL-DEPLETING There has been an ongoing decrease in Octopus pallidus CPUE from 2005/06 to the lowest level in 2011/12 where it remained in 2012/13 and 2013/14. This long term trend indicates that the associated level of effort is likely to ultimately result in overfishing. In 2014/15 CPUE increased, however the associated level of effort was at or above that historically linked with depleting the stock. It is possible that this increase is at least partly due to the highly stochastic nature of Octopus pallidus and a shift in effort to areas with higher CPUE. Octopus pallidus is therefore classified as transitional depleting. STOCK Tasmanian Octopus Fishery INDICATORS Catch, effort and CPUE trends The Tasmanian Octopus Fishery is a multi-species fishery in the Bass Strait primarily targeting Octopus pallidus and the less abundant Octopus tetricus (Table 1). The Scalefish Fishery Management Plan (revised in 2009) provides the management framework for the fishery. The (commercial) fishery is effectively a sole operator fishery with the same operator since its commencement in 1980. This arrangement is effective in ensuring profitability in the fishery and stewardship of the resource. In this assessment, the octopus fishery is described in terms of catch, effort and catch rates at the State level. A more detailed analysis of catch, effort and catch rates at the fishing block level is also presented. The commercial catch history for the period 2000/01 to 2014/15 is assessed. Catches have increased over the last decade and have fluctuated at around 85 tonnes since 2005/06. While fishing effort fluctuated around 300,000 potlifts for almost a decade, it increased to over 400,000 potlifts in 2012/13 and 2013/14 before declining to 342,000 potlifts in 2014/15, which was more consistent with the long-term average. Historically there have been strong seasonal patterns in catch per unit effort (CPUE), with CPUE highest during the brooding peak for the species (autumn). While CPUE was higher in the summer months during 2013/14, the 2014/15 season was more reflective of the norm. CPUE has declined since the recent peak in the mid-2000s and prior to the latest season had been at similar levels to those experienced in the early 2000s, which corresponded to a lower level of harvest. In the 2014/15 season, both the 50-pot sample and logbook data indicated an increase in CPUE in both number and weight respectively. The stochastic nature of CPUE over the last decade is reflective of the biology of the species, which is inherently linked to environmental conditions making it difficult to assess the state of the stock and impact of fishing mortality. Relative to the 2013/14 season, catch and effort increased in areas east of King Island (3D3 and 3D4) and within inshore waters off Stanley (4E3) but declined in areas offshore of Stanley (4E1). Fishers continue to respond to changes in CPUE by shifting effort (and therefore catch) from areas with lower CPUE to areas with higher CPUE. Bycatch of octopus from other commercial fisheries (mainly Octopus maorum from the rock lobster fishery) have decreased over time and have been relatively low over the last five years (around 8 tonnes on average). The recreational catch of octopus appears minimal with around IMAS Fishery Assessment Report Page 5 a tonne retained per annum. The impact of the fishery on bycatch and protected species is low due to the nature of the gear used (i.e. unbaited pots). The ongoing decrease in Octopus pallidus CPUE since 2005/06 suggests that the associated level of effort is too high and likely to ultimately result in overfishing. While CPUE increased in 2014/15 it remains below the reference year and fishing effort is still at or above that historically linked with depleting the stock. It is possible that the increase in CPUE is at least partly due to the highly stochastic nature of Octopus pallidus and a shift in effort to areas with higher CPUE. Fishing effort remains concentrated in the most productive areas or those close to port, which given the substantial stock structure within Octopus pallidus increases the potential for recruitment overfishing. A cap or effective limit on spatial fishing effort could improve the probability that CPUE would increase in the future and ensure that the composition and recruitment potential of Octopus pallidus is not impacted by concentrated fishing effort. IMAS Fishery Assessment Report Page 6 1. Introduction The fishery The Tasmanian Octopus Fishery has been operating since 1980. Prior to December 2009 the fishery operated under permit. Historically, access to the commercial fishery was provided to holders of a fishing licence (personal), a vessel licence and a scalefish or rock lobster licence via a trip limit of 100 kg. This limit also applies to recreational fishers. Since December 2009, a specific octopus licence was required to participate in the fishery. Two licenses were issued, belonging to the same operator. Since 1996, under the Offshore Constitutional Settlement (OCS) with the Commonwealth of Australia, Tasmania has assumed management control of the octopus fishery out to 200 nautical miles. The Tasmanian Octopus Fishery primarily targets the pale octopus (Octopus pallidus), with lesser targeted catches of the Gloomy octopus (Octopus tetricus) and the Maori octopus (Octopus maorum) also taken, primarily as byproduct. The main fishing method is unbaited moulded plastic pots (volume
Recommended publications
  • Stylet Elemental Signatures Indicate Population Structure in a Holobenthic Octopus Species, Octopus Pallidus
    Vol. 371: 1–10, 2008 MARINE ECOLOGY PROGRESS SERIES Published November 19 doi: 10.3354/meps07722 Mar Ecol Prog Ser OPENPEN ACCESSCCESS FEATURE ARTICLE Stylet elemental signatures indicate population structure in a holobenthic octopus species, Octopus pallidus Zoë A. Doubleday1,*, Gretta T. Pecl1, Jayson M. Semmens1, Leonid Danyushevsky2 1Marine Research Laboratories, Tasmanian Aquaculture & Fisheries Institute, University of Tasmania, Private Bag 49, Hobart, Tasmania 7001, Australia 2Centre for Ore Deposit Research, University of Tasmania, Private Bag 79, Hobart, Tasmania 7001, Australia ABSTRACT: Targeted trace elemental analysis was used to investigate the population structure and disper- sal patterns of the holobenthic octopus species Octopus pallidus (Hoyle, 1885). Multi-elemental signatures within the pre-hatch region of the stylet (an internal ‘shell’) were used to determine the common origins and levels of connectivity of individuals collected from 5 locations in Tasmania. To determine whether hatchling elemental signatures could be used as tags for natal ori- gin, hatchling stylets from 3 of the 5 locations were also analysed. We analyzed 12 elements using laser ablation inductively-coupled plasma-mass spectrometry (LA- ICPMS). Of the 12 elements, 7 were excellent spatial discriminators. There was evidence of high-level struc- turing with distinct groupings between all sites (the 2 closest being 85 km apart) within the adult O. pallidus Octopus pallidus, a holobenthic species found in south-east population, suggesting that all adults had hatched in or Australia near their respective collection sites. The hatchling sig- Photo: Stephen Leporati natures showed significant spatial variation, and a high percentage of individuals could successfully be traced back to their collection locations.
    [Show full text]
  • Octopus Consciousness: the Role of Perceptual Richness
    Review Octopus Consciousness: The Role of Perceptual Richness Jennifer Mather Department of Psychology, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada; mather@uleth.ca Abstract: It is always difficult to even advance possible dimensions of consciousness, but Birch et al., 2020 have suggested four possible dimensions and this review discusses the first, perceptual richness, with relation to octopuses. They advance acuity, bandwidth, and categorization power as possible components. It is first necessary to realize that sensory richness does not automatically lead to perceptual richness and this capacity may not be accessed by consciousness. Octopuses do not discriminate light wavelength frequency (color) but rather its plane of polarization, a dimension that we do not understand. Their eyes are laterally placed on the head, leading to monocular vision and head movements that give a sequential rather than simultaneous view of items, possibly consciously planned. Details of control of the rich sensorimotor system of the arms, with 3/5 of the neurons of the nervous system, may normally not be accessed to the brain and thus to consciousness. The chromatophore-based skin appearance system is likely open loop, and not available to the octopus’ vision. Conversely, in a laboratory situation that is not ecologically valid for the octopus, learning about shapes and extents of visual figures was extensive and flexible, likely consciously planned. Similarly, octopuses’ local place in and navigation around space can be guided by light polarization plane and visual landmark location and is learned and monitored. The complex array of chemical cues delivered by water and on surfaces does not fit neatly into the components above and has barely been tested but might easily be described as perceptually rich.
    [Show full text]
  • Comparison of Population Structuring in Sympatric Octopus Species with and Without a Pelagic Larval Stage
    Vol. 486: 203–212, 2013 MARINE ECOLOGY PROGRESS SERIES Published July 12 doi: 10.3354/meps10330 Mar Ecol Prog Ser Comparison of population structuring in sympatric octopus species with and without a pelagic larval stage Kaitlyn L. Higgins1,*, Jayson M. Semmens2, Zoë A. Doubleday3, Christopher P. Burridge1 1School of Zoology, University of Tasmania, Private Bag 5, Hobart, Tasmania 7001, Australia 2Fisheries, Aquaculture and Coasts Centre, Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 49, Hobart, Tasmania 7001, Australia 3Southern Seas Ecology Laboratories, School of Earth and Environmental Sciences, University of Adelaide, DX650 418, South Australia 5005, Australia ABSTRACT: An understanding of the influence of life history on dispersal capability is central to a range of disciplines within ecology and evolution. While studies have investigated this question by contrasting spatial population structuring in taxa that differ in life history, in the vast majority such comparisons differ in space and time, and therefore environmental factors may have con- tributed. Here, population structure of a holobenthic (i.e. direct developing) octopus, Octopus pal- lidus, was investigated genetically. This was compared to existing genetic data for a co-occurring merobenthic (i.e. planktonic larvae) species, Macroctopus maorum. Greater spatial genetic struc- turing was evident in O. pallidus than M. maorum. Patterns were consistent with isolation by dis- tance in O. pallidus, but appeared related to oceanographic circulation systems in M. maorum, suggesting distance-dependent adult dispersal and current-mediated larval dispersal, respec- tively. Genetic population structuring in O. pallidus also largely corroborated inferences based on stylet microchemistry, indicating the utility of these environmental signatures.
    [Show full text]
  • Life History, Mating Behavior, and Multiple Paternity in Octopus
    LIFE HISTORY, MATING BEHAVIOR, AND MULTIPLE PATERNITY IN OCTOPUS OLIVERI (BERRY, 1914) (CEPHALOPODA: OCTOPODIDAE) A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI´I AT MĀNOA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN ZOOLOGY DECEMBER 2014 By Heather Anne Ylitalo-Ward Dissertation Committee: Les Watling, Chairperson Rob Toonen James Wood Tom Oliver Jeff Drazen Chuck Birkeland Keywords: Cephalopod, Octopus, Sexual Selection, Multiple Paternity, Mating DEDICATION To my family, I would not have been able to do this without your unending support and love. Thank you for always believing in me. ii ACKNOWLEDGMENTS I would like to thank all of the people who helped me collect the specimens for this study, braving the rocks and the waves in the middle of the night: Leigh Ann Boswell, Shannon Evers, and Steffiny Nelson, you were the hard core tako hunters. I am eternally grateful that you sacrificed your evenings to the octopus gods. Also, thank you to David Harrington (best bucket boy), Bert Tanigutchi, Melanie Hutchinson, Christine Ambrosino, Mark Royer, Chelsea Szydlowski, Ily Iglesias, Katherine Livins, James Wood, Seth Ylitalo-Ward, Jessica Watts, and Steven Zubler. This dissertation would not have happened without the support of my wonderful advisor, Dr. Les Watling. Even though I know he wanted me to study a different kind of “octo” (octocoral), I am so thankful he let me follow my foolish passion for cephalopod sexual selection. Also, he provided me with the opportunity to ride in a submersible, which was one of the most magical moments of my graduate career.
    [Show full text]
  • Environmental Effects on Cephalopod Population Dynamics: Implications for Management of Fisheries
    Advances in Cephalopod Science:Biology, Ecology, Cultivation and Fisheries,Vol 67 (2014) Provided for non-commercial research and educational use only. Not for reproduction, distribution or commercial use. This chapter was originally published in the book Advances in Marine Biology, Vol. 67 published by Elsevier, and the attached copy is provided by Elsevier for the author's benefit and for the benefit of the author's institution, for non-commercial research and educational use including without limitation use in instruction at your institution, sending it to specific colleagues who know you, and providing a copy to your institution’s administrator. All other uses, reproduction and distribution, including without limitation commercial reprints, selling or licensing copies or access, or posting on open internet sites, your personal or institution’s website or repository, are prohibited. For exceptions, permission may be sought for such use through Elsevier's permissions site at: http://www.elsevier.com/locate/permissionusematerial From: Paul G.K. Rodhouse, Graham J. Pierce, Owen C. Nichols, Warwick H.H. Sauer, Alexander I. Arkhipkin, Vladimir V. Laptikhovsky, Marek R. Lipiński, Jorge E. Ramos, Michaël Gras, Hideaki Kidokoro, Kazuhiro Sadayasu, João Pereira, Evgenia Lefkaditou, Cristina Pita, Maria Gasalla, Manuel Haimovici, Mitsuo Sakai and Nicola Downey. Environmental Effects on Cephalopod Population Dynamics: Implications for Management of Fisheries. In Erica A.G. Vidal, editor: Advances in Marine Biology, Vol. 67, Oxford: United Kingdom, 2014, pp. 99-233. ISBN: 978-0-12-800287-2 © Copyright 2014 Elsevier Ltd. Academic Press Advances in CephalopodAuthor's Science:Biology, personal Ecology, copy Cultivation and Fisheries,Vol 67 (2014) CHAPTER TWO Environmental Effects on Cephalopod Population Dynamics: Implications for Management of Fisheries Paul G.K.
    [Show full text]
  • Targeted Review of Biological and Ecological Information from Fisheries Research in the South East Marine Region
    TARGETED REVIEW OF BIOLOGICAL AND ECOLOGICAL INFORMATION FROM FISHERIES RESEARCH IN THE SOUTH EAST MARINE REGION FINAL REPORT B. D. Bruce, R. Bradford, R. Daley, M. Green and K. Phillips December 2002 Client: National Oceans Office Targeted review of biological and ecological information from fisheries research in the South East Marine Region Final Report B. D. Bruce, R. Bradford, R. Daley M. Green and K. Phillips* CSIRO Marine Research, Hobart * National Oceans Office December 2002 2 Table of Contents: Table of Contents:...................................................................................................................................3 Introduction.............................................................................................................................................5 Objective of review.............................................................................................................................5 Structure of review..............................................................................................................................5 Format.................................................................................................................................................6 General ecological/biological issues and uncertainties for the South East Marine Region ....................9 Specific fishery and key species accounts ............................................................................................10 South East Fishery (SEF) including the South East Trawl
    [Show full text]
  • Stock Assessment of Targeted Invertebrates at Ningaloo Reef
    Western Australian Marine Science Institution (WAMSI) Node 3 Project 3.1.3 Stock assessment of targeted invertebrates at Ningaloo Reef y Martial Depczynski y Andrew Heyward y Ben Radford y Rebecca O’Leary (AIMS) y Russ Babcock y Mick Haywood y Damian Thomson (CSIRO) Final Report by AIMS/CSIRO to WAMSI as contribution to deliverables for WAMSI project 3.1.3 November 2009 Australian Institute of Marine Science PMB No 3 PO Box 41775 The UWA Oceans Institute (M096) Townsville MC Qld 4810 Casuarina NT 0811 Crawley WA 6009 This report should be cited as: Depczynski M, Heyward A, Radford B, O'Leary R, Babcock R, Haywood M, Thomson D (2009) Stock assessment of targeted invertebrates at Ningaloo Reef. WAMSI Node 3 Project 3.1.3. Final Report to the Western Australian Marine Science Institution, Perth. 108 p. DISCLAIMER While reasonable efforts have been made to ensure that the contents of this document are factually correct, AIMS does not make any representation or give any warranty regarding the accuracy, completeness, currency or suitability for any particular purpose of the information or statements contained in this document. To the extent permitted by law AIMS shall not be liable for any loss, damage, cost or expense that may be occasioned directly or indirectly through the use of or reliance on the contents of this document. WAMSI Project 3.1.3: Invertebrate stock assessment at Ningaloo Reef Table of Contents List of Figures.................................................................................................................
    [Show full text]
  • Rapid Assessment of Sustainability for Ecological Risk of Shark and Other
    Rapid assessment of sustainability for ecological risk of shark and other chondrichthyan bycatch species taken in the Southern and Eastern Scalefish and Shark Fishery Terence I. Walker, John D. Stevens, J. Matias Braccini, Ross K. Daley, Charlie Huveneers, Sarah B. Irvine, Justin D. Bell, Javier Tovar‐Ávila, Fabian I. Trinnie, David T. Phillips, Michelle A. Treloar, Cynthia A. Awruck, Anne S. Gason, John Salini, and William C. Hamlett Project No. 2002/033 Rapid assessment of sustainability for ecological risk of shark and other chondrichthyan bycatch species taken in the Southern and Eastern Scalefish and Shark Fishery Terence I. Walker, John D. Stevens, J. Matias Braccini, Ross K. Daley, Charlie Huveneers, Sarah B. Irvine, Justin D. Bell, Javier Tovar‐ Ávila, Fabian I. Trinnie, David T. Phillips, Michelle A. Treloar, Cynthia A. Awruck, Anne S. Gason, John Salini, and William C. Hamlett July 2008 Project Number 2002/033 Rapid assessment of sustainability for ecological risk of shark and other chondrichthyan bycatch species taken in the Southern and Eastern Scalefish and Shark Fishery FRDC Report 2002/033 Terence I. Walker, John D. Stevens, J. Matias Braccini, Ross J. Daley, Charlie Huveneers, Sarah B. Irvine, Justin D. Bell, Javier Tovar‐ Ávila, Fabian I. Trinnie, David T. Phillips, Michelle A. Treloar, Cynthia A. Awruck, Anne S. Gason, John Salini, and Hamlett, W. C. Published by Department of Primary Industries, Fisheries Research Brand, Queenscliff, Victoria, 3225. © Fisheries Research and Development Corporation, and Fisheries Victoria. 2008 This work is copyright. Except as permitted under the Copyright Act 1968 (Cth), no part of this publication may be reproduced by any process, electronic or otherwise, without the specific written permission of the copyright owners.
    [Show full text]
  • Seasonal Occurrence of Japanese Pygmy Octopus Octopus Parvus in the Intertidal
    bioRxiv preprint doi: https://doi.org/10.1101/2021.03.14.435358; this version posted March 15, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 Seasonal occurrence of Japanese pygmy octopus Octopus parvus in the intertidal 2 zone 3 4 Yuta Yamate¹, Takumi Ohya2, Toshifumi Wada3,4, and Takeshi Takegaki¹ 5 6 1. Graduate School of Fisheries and Environmental Sciences, Nagasaki University, 1- 7 14 Bunkyo-machi, Nagasaki, Nagasaki 852-8521, Japan 8 2. Faculty of Fisheries, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, Nagasaki 9 852-8521, Japan 10 3. Institute of Natural and Environmental Sciences, University of Hyogo, 6 11 Yayoigaoka, Sanda, Hyogo 669-1546, Japan 12 4. Museum of Nature and Human Activities, Hyogo, 6 Yayoigaoka, Sanda, Hyogo 669- 13 1546, Japan 14 15 Corresponding author: 16 Yuta Yamate (Tell: +81-80-4556-5830) 17 Takeshi Takegaki (Tell & Fax: +81-95-819-2819) 18 19 E-mail address 20 Yuta Yamate: taketakeyake@gmail.com 21 Takumi Ohya: bb45116022@ms.nagasaki-u.ac.jp 22 Toshifumi Wada (deceased): wada@hitohaku.jp 23 Takeshi Takegaki: takegaki@nagasaki-u.ac.jp 24 1 bioRxiv preprint doi: https://doi.org/10.1101/2021.03.14.435358; this version posted March 15, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 25 Abstract 26 The Japanese pygmy octopus Octopus parvus is a small octopus that occurs commonly 27 along the coast of southern Japan, and is caught using traditional fishing methods.
    [Show full text]
  • Population Biology and Ecology of the North Pacific Giant Octopus in the Eastern Bering Sea
    Population biology and ecology of the North Pacific giant octopus in the eastern Bering Sea Item Type Thesis Authors Brewer, Reid Download date 10/10/2021 20:56:08 Link to Item http://hdl.handle.net/11122/6804 POPULATION BIOLOGY AND ECOLOGY OF THE NORTH PACIFIC GIANT OCTOPUS IN THE EASTERN BERING SEA By Reid S. Brewer, B.S., M.S. A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Marine Biology University of Alaska Fairbanks August 2016 APPROVED: Brenda L. Norcross, Committee Chair Andrew C. Seitz, Committee Member Arny L. Blanchard, Committee Member Olav A. Ormseth, Committee Member Sherry L. Tamone, Committee Member Sarah M. Hardy, Chair Department of Marine Biology Bradley S. Moran, Dean School of Fisheries and Ocean Sciences TBD, Graduate School Dean Abstract The North Pacific giant octopus (Enteroctopus dofleini) is an important member of pan-Pacific coastal ecosystems and represents a large incidental catch in Alaska; however little is known about the biology and ecology of this species, which hinders management. To improve our understanding of E. dofleini biology, I conducted a multiyear tagging study in a 25 km2 study area in the eastern Bering Sea (EBS). I used Visible Implant Elastomers to determine growth and movement patterns for E. dofleini and sacrificed octopus were examined to determine seasonal and sex-specific reproductive characteristics. Using tagging data and Cormack-Jolly- Seber models, I estimated survival and study-area abundance for E. dofleini and expanded the abundance estimates to neighboring areas where most of the incidental catch of octopus occurs.
    [Show full text]
  • Cephalopod Hatchling Growth: the Effects of Initial Size and Seasonal Temperatures
    Mar Biol (2007) 151:1375–1383 DOI 10.1007/s00227-006-0575-y RESEA R CH ARTICL E Cephalopod hatchling growth: the effects of initial size and seasonal temperatures Stephen C. Leporati Æ Gretta T. Pecl Æ Jayson M. Semmens Received: 14 September 2006 / Accepted: 28 November 2006 / Published online: 19 December 2006 © Springer-Verlag 2006 Abstract Temperature is known to have a strong 1.60% bwd–1. Initial size influenced subsequent growth, influence on cephalopod growth during the early however, this was dependent on feeding rate and ap­ exponential growth phase. Most captive growth studies pears to be secondary to the effects of temperature. have used constant temperature regimes and assumed that populations are composed of identically sized individuals at hatching, overlooking the effects of seasonal temperature variation and individual hatch­ Introduction ling size heterogeneity. This study investigated the relative roles of initial hatchling size and simulated Cephalopod growth is highly variable and influenced natural seasonal temperature regimes on the growth of by biotic and abiotic factors such as temperature, diet, 64 captive Octopus pallidus over a 4-month period. age, gender and level of maturity (Forsythe 1984, 1993; Initial weights were recorded, and daily food con­ Forsythe and Van Heukelem 1987; Forsythe and sumption and fortnightly growth monitored. Two Hanlon 1988). Individual growth variation can influ­ temperature treatments were applied replicating local ence many facets of a cephalopod population including seasonal water temperatures: spring/summer (14–18°C) size and age structure, reproductive dynamics, and and summer/autumn (18–14°C). Overall octopuses in survival rate of hatchlings, all of which in turn can af­ the spring/summer treatment grew at a rate of 1.42% fect local abundance levels and therefore fisheries.
    [Show full text]
  • Stock Structure of the English Channel Common Cuttlefish Sepia Officinalis
    Stock structure of the English Channel common cuttlefish Sepia officinalis (Linnaeus, 1758) during the reproduction period Michael Gras, Georges Safi, Hugo Lebredonchel, Jérôme Quinquis, Eric Foucher, Noussithé Kouéta, Jean-Paul Robin To cite this version: Michael Gras, Georges Safi, Hugo Lebredonchel, Jérôme Quinquis, Eric Foucher, et al.. Stock structure of the English Channel common cuttlefish Sepia officinalis (Linnaeus, 1758) during the reproduction period. Journal of the Marine Biological Association of the UK, Cambridge University Press (CUP), 2016, 96 (1), pp.167-176. 10.1017/S0025315415001162. hal-02141747 HAL Id: hal-02141747 https://hal.archives-ouvertes.fr/hal-02141747 Submitted on 28 May 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. TITLE: STOCK STRUCTURE OF THE ENGLISH CHANNEL COMMON CUTTLEFISH (SEPIA OFFICINALIS (LINNAEUS, 1758) DURING THE REPRODUCTION PERIOD; CONSIDERED IN THE CONTEXT OF WARMING AND HIGH FISHING PRESSURE Alternative title: Sepia officinalis (Linnaeus, 1758) life cycle in the English Channel, any modifications between 1980 and 2011 ? Authors names: Michaël, GRAS1, Georges, SAFI, Hugo, LEBREDONCHEL, Jérôme, QUINQUIS, Eric, FOUCHER, Noussithé, KOUETA, Jean-Paul, ROBIN Full postal adresses: 1-Université de Caen Basse-Normandie, UMR BOREA : Biologie des ORganismes et des Ecosystèmes Aquatiques, Esplanade de la paix, CS 14032, 14032 Caen, France.
    [Show full text]