Fisheries Research Report No. 248, 2013 Status of nearshore finfish stocks in south-western Western Australia Part 3: Whiting (Sillaginidae) NRM Project 09003 J. Brown, C. Dowling, A. Hesp, K. Smith and B. Molony Fisheries Research Division Western Australian Fisheries and Marine Research Laboratories PO Box 20 NORTH BEACH, Western Australia 6920 Correct citation: Brown, J., Dowling, C., Hesp, A., Smith, K., and Molony, B. 2013. Status of nearshore finfish stocks in south- western Western Australia. Part 3: Whiting (Sillaginidae). Fisheries Research Report No. 248. Department of Fisheries, Western Australia. 128pp. Enquiries: WA Fisheries and Marine Research Laboratories, PO Box 20, North Beach, WA 6920 Tel: +61 8 9203 0111 Email: [email protected] Website: www.fish.wa.gov.au ABN: 55 689 794 771 A complete list of Fisheries Research Reports is available online at www.fish.wa.gov.au Cover: Whiting. Illustration © R. Swainston/www.anima.net.au © Department of Fisheries, Western Australia. September 2013. ISSN: 1035 - 4549 ISBN: 978-1-921845-68-0 ii Fisheries Research Report [Western Australia] No. 248, 2013 Contents Executive summary .............................................................................................................. 1 1.0 Introduction .................................................................................................................. 5 1.1 Background ............................................................................................................. 5 1.2 Need ........................................................................................................................ 6 1.3 Resource assessment framework – indicator species ............................................. 7 1.4 Weight-of-evidence assessment .............................................................................. 7 1.5 Objectives ............................................................................................................... 7 1.6 Overview of whiting species of Western Australia ................................................ 8 2.0 Methods ......................................................................................................................... 11 2.1 Fishery catch composition ...................................................................................... 11 2.1.1 Species identification ................................................................................... 11 2.1.2 Sample collection ......................................................................................... 11 2.1.3 Catch shares ................................................................................................. 12 2.2 Assessment.............................................................................................................. 12 2.2.1 Biological analysis ....................................................................................... 12 2.2.2 Recruitment dynamics ................................................................................. 17 2.2.3 Recreational fishery catch and effort ........................................................... 18 2.2.4 Commercial fishery catch and effort ........................................................... 21 3.0 Results............................................................................................................................ 23 3.1 Fishery catch composition ...................................................................................... 23 3.1.1 Species identification ................................................................................... 23 3.1.2 Recreational catch composition ................................................................... 24 3.1.3 Commercial catch composition ................................................................... 27 3.1.4 Catch shares ................................................................................................. 27 3.2 Assessment.............................................................................................................. 27 3.2.1 Biological analyses ...................................................................................... 27 3.2.1.1 Southern school whiting ................................................................ 28 3.2.1.2 King George whiting ..................................................................... 31 3.2.1.3 Other whiting species .................................................................... 33 3.2.2 Recruitment dynamics ................................................................................. 34 3.2.2.1 Southern school whiting ................................................................ 34 3.2.2.2 King George whiting ..................................................................... 35 3.2.3 Recreational fishery catch and effort ........................................................... 35 3.2.3.1 Southern school whiting ................................................................ 36 3.2.3.2 King George whiting ..................................................................... 38 3.2.4 Commercial fishery catch and effort ........................................................... 40 3.2.4.1 Southern school whiting ................................................................ 43 3.2.4.2 King George whiting ..................................................................... 43 Fisheries Research Report [Western Australia] No. 248, 2013 iii 4.0 Discussion ...................................................................................................................... 45 4.1 Fishery catch composition ...................................................................................... 45 4.1.1 Species identification ................................................................................... 45 4.1.2 Species compositions of whiting catches .................................................... 45 4.2 Assessment.............................................................................................................. 47 4.2.1 Biological assessment .................................................................................. 47 4.2.1.1 Southern school whiting ................................................................ 47 4.2.1.2 King George whiting ..................................................................... 50 4.2.1.3 Other whiting (Sillago) species ..................................................... 53 4.2.2 Recruitment dynamics ................................................................................. 53 4.2.3 Recreational fishery catch and effort ........................................................... 55 4.2.4 Commercial fishery catch and effort ........................................................... 58 5.0 ‘Weight-of-evidence’ assessment and implications ................................................... 60 5.1 Summary of stock status ......................................................................................... 60 5.1.1 Southern school whiting .............................................................................. 60 5.1.2 King George whiting ................................................................................... 62 6.0 Acknowledgements ....................................................................................................... 65 7.0 References ..................................................................................................................... 66 8.0 Appendices .................................................................................................................... 121 Appendix 1. Whiting identification article published in the Research Angler Program newsletter (April 2011) to assist with improved reporting of individual whiting species of the West Coast Bioregion. ......................................................................................... 121 Appendix 2. Sagittae otoliths of whiting species of south-western Western Australia. .. 122 Appendix 3. Photographs of stout whiting from a) Western Australia and b) New South Wales. ................................................................................................................... 123 iv Fisheries Research Report [Western Australia] No. 248, 2013 Executive summary The whiting family (Sillaginidae) is common in nearshore waters of south-western Western Australia (WA) where it is highly valued by recreational and commercial fishers. The importance of these species to recreational fishers is reflected in this category of fishes being ranked as the most or 2nd most retained finfish species group by boat- and shore-based fishers in several recreational fishing surveys in WA. Whiting are commercially important in a number of fisheries, with total state catches averaging over 200 tonnes per annum since 1980. The composition of the whiting catch, however, is largely unknown, with a number of whiting species potentially contributing substantially to the overall catch of this family. The recreational and commercial fisheries that capture whiting can therefore be considered very data-limited, due to the lack of species-specific data that prohibit a robust assessment of the status of the stocks of the different whiting species. The main purpose of this report is to determine the species composition of whiting landings caught recreationally and commercially in south-western WA. This report then investigates the stock status of the key (most abundant)