FRDC FINAL REPORT NATIONAL STRATEGY FOR THE SURVIVAL OF RELEASED LINE CAUGHT FISH: MAXIMISING POST-RELEASE SURVIVAL IN LINE CAUGHT FLATHEAD TAKEN IN SHELTERED COASTAL WATERS J.M. Lyle, I.W. Brown, N.A. Moltschaniwskyj, D. Mayer, and W. Sawynok November 2006 FRDC Project No. 2004/071 National Library of Australia Cataloguing-in-Publication Entry Lyle, Jeremy Martin, 1955 - National strategy for the survival of released line caught fish: maximising post-release survival in line caught flathead taken in sheltered coastal waters Bibliography. Includes index. ISBN 1 86295 369 4. 1. Fishery management - Australia. 2. Fish populations - Australia. 3. Platycephalidae - Effect of stress on - Australia. 4. Platycephalidae - Mortality - Australia. I. Lyle, J. M. II. Tasmanian Aquaculture and Fisheries Institute. 639.2750994 Published by the Marine Research Laboratories – Tasmanian Aquaculture and Fisheries Institute, University of Tasmania, Private Bag 49, Hobart, Tasmania 7001. E-mail: [email protected] Ph. (03) 6227 7277 Fax: (03) 6227 8035 The opinions expressed in this report are those of the author/s and are not necessarily those of the Tasmanian Aquaculture and Fisheries Institute, Queensland Department of Primary Industries and Fisheries or the Fisheries Research and Development Corporation. 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. Neither may information be stored electronically in any form whatsoever without such permission. The Fisheries Research and Development Corporation plans, invests in and manages fisheries research and development throughout Australia. It is a statutory authority within the portfolio of the federal Minister for Agriculture, Fisheries and Forestry, jointly funded by the Australian Government and the fishing industry. © Fisheries Research and Development Corporation and Tasmanian Aquaculture and Fisheries Institute and Queensland Department of Primary Industries and Fisheries 2006 FINAL REPORT NATIONAL STRATEGY FOR THE SURVIVAL OF RELEASED LINE CAUGHT FISH: MAXIMISING POST-RELEASE SURVIVAL IN LINE CAUGHT FLATHEAD TAKEN IN SHELTERED COASTAL WATERS J.M. Lyle, I.W. Brown, N.A. Moltschaniwskyj, D. Mayer, and W. Sawynok, November 2006 FRDC Project No. 2004/071 Tasmanian Aquaculture and Fisheries Institute and Queensland Department of Primary Industries and Fisheries TABLE OF CONTENTS NON TECHNICAL SUMMARY: ...................................................................... 1 ACKNOWLEDGEMENTS .......................................................................................... 5 BACKGROUND ............................................................................................................ 6 NEED .............................................................................................................................. 7 OBJECTIVES ................................................................................................................ 8 CHAPTER 1: EFFECTS OF HOOKING DAMAGE AND POTENTIAL IMPACT OF HOOK TYPE ON POST-RELEASE SURVIVAL OF SAND FLATHEAD (PLATYCEPHALUS BASSENSIS)........................................................ 9 1.1 Introduction........................................................................................................ 9 1.2 Methods............................................................................................................. 10 1.2.1 Post release survival experiments ......................................................................................10 1.2.2 Fishing trials ......................................................................................................................12 1.2.3 Fishing diary ......................................................................................................................13 1.2.4 Data Analysis.....................................................................................................................13 1.3 Results............................................................................................................... 15 1.3.1 Post release survival experiments ......................................................................................15 1.3.2 Hook types – catch rates and deep hooking .......................................................................21 1.4 Discussion ......................................................................................................... 25 CHAPTER 2: EFFECTS OF HOOKING DAMAGE ON POST RELEASE SURVIVAL OF DUSKY FLATHEAD (PLATYCEPHALUS FUSCUS)................ 30 2.1 Introduction...................................................................................................... 30 2.2 Methods............................................................................................................. 31 2.2.1 Study area ..........................................................................................................................32 2.2.2 Angler involvement ...........................................................................................................32 2.2.3 Experimental protocol........................................................................................................33 2.2.4 Data collection ...................................................................................................................35 2.2.5 Data analysis ......................................................................................................................35 2.3 Results............................................................................................................... 36 2.3.1 Catch characteristics ..........................................................................................................37 2.3.2 Post release survival experiment........................................................................................39 2.4 Discussion ......................................................................................................... 53 Page i FRDC Project 2004/071 CHAPTER 3: DEEP HOOKING AND POTENTIAL EFFECTS FISHING WITH BAIT AND LURES ON POST RELEASE SURVIVAL IN FLATHEAD .............58 3.1 Introduction ......................................................................................................58 3.2 Methods.............................................................................................................59 3.2.1 Data sources .......................................................................................................................59 3.2.2 Data analysis ......................................................................................................................60 3.3 Results ...............................................................................................................60 3.3.1 Sand flathead......................................................................................................................60 3.3.2 Dusky Flathead...................................................................................................................63 3.4 Discussion..........................................................................................................66 BENEFITS ....................................................................................................................70 FURTHER DEVELOPMENT....................................................................................70 PLANNED OUTCOMES ............................................................................................71 CONCLUSION.............................................................................................................71 REFERENCES.............................................................................................................75 APPENDIX 1: INTELLECTUAL PROPERTY ......................................................80 APPENDIX 2: STAFF ................................................................................................80 APPENDIX 3: FLATHEAD SURVIVAL BROCHURE.........................................81 FRDC Project 2004/071 Page ii 2004/071 National strategy for the survival of released line caught fish: maximising post-release survival in line caught flathead taken in sheltered coastal waters PRINCIPAL INVESTIGATOR: Dr J.M. Lyle ADDRESS: University of Tasmania Tasmanian Aquaculture and Fisheries Institute Private Bag 49 Hobart TAS 7001 Telephone: 03 6227 7277 Fax: 03 6227 8035 OBJECTIVES: 1. Estimate post-release survival (PRS) rates for key flathead species associated with current hook and line fishing practices. 2. Evaluate the suitability of circle and non-traditional hooks in terms of enhancing PRS and minimising hooking damage. 3. Based on objectives 1 and 2 develop protocols that can be readily applied to maximize PRS in flathead. NON TECHNICAL SUMMARY: Flathead represent the largest catch of any fish group taken by recreational fishers in Australia and, after bream, account for the greatest numbers of fish released by recreational fishers (National Recreational Fishing Survey). Flathead are taken around Australia, with catches concentrated in the eastern states, including Tasmania. Sand flathead (Platycephalus bassensis) is the dominant species taken in estuarine and sheltered inshore waters of Tasmania and Victoria whereas dusky flathead (P. fuscus) is the main species taken from