CORE Metadata, citation and similar papers at core.ac.uk Provided by Research Repository FRDC Project 96/105 STOCK ASSESSMENT OF AUSTRALIAN HERRING S. G. Ayvazian, G. K. Jones, D. Fairclough, I. C. Potter, B. S. Wise and W. F. Dimmlich 2000 Fisheries Western Australia – Research Division PO Box 20, North Beach, Western Australia 6020 South Australian Research and Development Institute (SARDI) PO Box 120, Henley Beach, South Australia 5022 INSTITUTE Murdoch University South St Murdoch, Perth, Western Australia 6150 ISBN 0 7309 8447 8 1 TABLE OF CONTENTS NON-TECHNICAL SUMMARY..........................................................................................................1 BACKGROUND.....................................................................................................................................3 NEED.......................................................................................................................................................4 OBJECTIVES.........................................................................................................................................6 RATIONALE AND APPROACH.........................................................................................................6 CHAPTER 1. A DESCRIPTION OF THE COMMERCIAL AND RECREATIONAL FISHERY FOR AUSTRALIAN HERRING (ARRIPIS GEORGIANA) IN SOUTHERN AUSTRALIAN WATERS – HISTORY OF DEVELOPMENT, METHODS OF CAPTURE AND VALUES ........7 Western Australia...............................................................................................................................7 Description of the commercial fishery and its history of development.............................................7 Methods and areas of capture ......................................................................................................9 Description of the recreational fishery and its history of development ..........................................10 Methods and areas of capture ....................................................................................................11 Recreational catch, effort and CPUE.........................................................................................11 Value of the recreational fishery ................................................................................................13 South Australia .................................................................................................................................13 Description of the commercial fishery and its history of development...........................................13 Methods and areas of capture in 1996-98..................................................................................17 Gross value of production of the commercial fishery.................................................................19 Description of the recreational fishery and its history of development ..........................................20 Current methods and areas of capture .......................................................................................21 Recreational catch, effort and CPUE.........................................................................................22 Expenditure in the recreational fishery ......................................................................................23 Victoria..............................................................................................................................................23 The commercial fishery ..................................................................................................................23 Gross value of production of the fishery.....................................................................................24 The recreational fishery.................................................................................................................. 24 Expenditure in the recreational fishery ......................................................................................24 References .........................................................................................................................................25 CHAPTER 2. REPRODUCTION, AGE AND GROWTH OF AUSTRALIAN HERRING (ARRIPIS GEORGIANA).....................................................................................................................28 Introduction ......................................................................................................................................28 Materials and methods.....................................................................................................................31 Sampling locations and methods ....................................................................................................31 Sea surface temperatures................................................................................................................ 31 Reproduction ..................................................................................................................................32 Gonadal variables .......................................................................................................................32 Length and age at first maturity..................................................................................................33 Fecundity....................................................................................................................................34 Age and growth...............................................................................................................................34 Determination of the appropriate structure for ageing Arripis georgiana...................................34 Analysis of data ..........................................................................................................................35 Results................................................................................................................................................36 Sea surface temperatures................................................................................................................ 36 Reproduction ..................................................................................................................................36 South-western Australia .............................................................................................................36 i Gonadosomatic indices and maturity stages...............................................................................36 Oocyte stages and diameter frequencies.....................................................................................39 Length and age at maturity .........................................................................................................42 Fecundity....................................................................................................................................44 Eastern south coast region of Western Australia and South Australia........................................ 48 Gonadosomatic indices and maturity stages...............................................................................48 Sex ratios for Western Australia and South Australia ................................................................48 Age and growth...............................................................................................................................51 Validation of the ageing technique .............................................................................................51 Length and age composition and growth curves for Arripis georgiana in south-western Australia .................................................................................................................................................... 53 Length and age compositions of Arripis georgiana in the eastern south coast region of Western Australia and the South Australian region..................................................................................57 Patterns of growth in different regions .......................................................................................60 Discussion ..........................................................................................................................................60 Reproduction ..................................................................................................................................60 Spawning location and timing ....................................................................................................60 Relationship between spawning time and water temperature.....................................................62 Spawning frequency and fecundity............................................................................................. 64 Sex ratios ....................................................................................................................................64 Length and age at maturity and management implications......................................................... 64 Age and growth...............................................................................................................................65 Validation of the use of otoliths for ageing Arripis georgiana.................................................... 65 Dispersal of larval and juvenile Arripis georgiana .....................................................................66 Spawning