I & I NSW Wild research Program ( robusta)

Exploitation Status Moderately fished

A small, fast growing caught by in waters. The stock is shared with and the status has been adopted from the Queensland assessment.

Scientific name Standard name comment

Sillago robusta stout whiting

Sillago robusta Image © Bernard Yau

Background Stout whiting (Sillago robusta) is a sub-tropical recently increased from this level. It is likely that species that occurs in ocean waters to a depth trawlers targeting have continued to of 70 m around northern from WA discard significant quantities of stout whiting to northern NSW. Stout whiting off southern throughout this period. Queensland and northern NSW are thought to Stout whiting are not taken in significant belong to a single ‘eastern’ Australian stock. quantities by any other commercial or Both (S. flindersi) and recreational fisheries in NSW. A targeted stout whiting are taken by trawling in inshore trawl for stout whiting off southern ocean waters, and the two species may occur Queensland has seen declining effort and in the same trawl catch off northern NSW. catch since the mid 1990s. Recent landings Historically both species were reported by have been around 500 - 1000 t annually, from fishers as ‘school whiting’ and catches of each a maximum of 5 vessels participating in the species were estimated according to latitude fishery. Stout whiting are also taken as a by- were the catch was taken. Since July 2009, catch of trawling off Queensland, but fishers have been required to report the two the bulk of these catches are discarded at sea. species separately. The annual discarded catch was estimated to be around 4000 t during the 1990s, however NSW trawlers generally discarded stout whiting annual discards are estimated to have declined until an export market developed in the 1970s. to around 1500 t recently. Landings increased to around 300 t in the mid-late 1980s, declined to very low levels There has been considerable research into in the mid 1990s, and rose again to around the biology of stout whiting off southern 500 t in the late 1990s. The decline in landings Queensland. The species reaches a maximum around 2000 was apparently associated with age of eight years and length of 23 cm fork the introduction of reduction devices length (FL), although the bulk of catches is into the prawn trawl fishery, but catches have comprised of from 1 – 2 years of age and 14 to 18 cm FL. Sexual maturity is reached

status of fisheries resources in nsw, 2008/09 stout whiting | p 323 wild fisheries research program

at about 2 years of age, at about 15 cm FL. Landings by Commercial Fishery of Stout Whiting Information on the distribution and size composition of stout whiting off NSW is Ocean Prawn Trawl (Primary Species) available from research trawls conducted by

Fisheries Research Vessel Kapala. 500 400

Additional Notes 300

• This is a short-lived species with no significant Landings (t) 200 recreational fishery.

• The stock is shared with Queensland, whose 100

few operators are managed with catch quotas 0 (currently 1250 t). 97/98 99/00 01/02 03/04 05/06 07/08 Financial Year • Recent research has provided growth rate and size at maturity estimates for the NSW area. Reported landings of stout whiting by NSW commercial fisheries from 1997/98. Fisheries which contribute less • Some limited information is available on than 2.5% of the landings are excluded for clarity and the size composition of NSW commercial privacy. landings, and a recent research project at I & I NSW studied growth and reproductive Catch Per Unit Effort Information of Stout Whiting biology of stout whiting from northern NSW. Harvested by Ocean Prawn Trawling in NSW • There is no minimum legal length for stout 1.0 whiting which are included in a combined recreational bag limit of 20 for all whiting. 0.8

Catch 0.6 Recreational Catch of Stout Whiting 0.4

The annual recreational harvest of stout whiting Relative Catch Rate in NSW is likely to be less than one tonne. 0.2 0.0 Historical Landings of Stout Whiting 98/99 00/01 02/03 04/05 06/07 08/09 Financial Year Catch rates of stout whiting harvested using ocean prawn

500 trawling for NSW. Two indicators are provided: (1) median catch rate (lower solid line); and (2) 90th percentile of the catch rate (upper dashed line). Note that catch rates 400 are not a robust indicator of abundance in many cases. Caution should be applied when interpreting these

300 results. Landings (t) 200 Growth Curve of Stout Whiting

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100 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 20 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 0 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 88/89 93/94 98/99 03/04 08/09 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 15 ● ● ● Financial Year ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● Commercial landings (including available historical ● ● ● ● FL (cm) ● ● ● ● 10 ● ● ● ● records) of stout whiting for NSW from 1984/85 to ● ● ● ● ● ● ● ● ● ● ● ● ● ● 2008/09 for all fishing methods. ● ● 5

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● 0

0 2 4 6 8 10 Age (years)

Age-length data with fitted growth curve of stout whiting (internal data). Lengths are presented as fork length (FL). p 324 | Stout Whiting status of fisheries resources in nsw, 2008/09

Length Frequency of Stout Whiting Further Reading 1989/90−1991/92

0.15 n = 10 226 Broadhurst, M.K., D.J. Young, C.A. Gray and M.E.L. Wooden (2005). Improving selection in south eastern Australian whiting (Sillago spp.) trawls: effects of modifying the body, extension and 0.10 codend, Scientia Marina 69: 301-311.

Proportion Broadhurst, M.K., K.K.P. Dijkstra, D.D. Reid and C.A.

0.05 Gray (2006). Utility of morphological data for key fish species in southeastern Australian -seine and otter-trawl fisheries: predicting mesh size and

0.00 configuration.New Zealand Journal of Marine and 0 10 20 30 40 Freshwater Research 40 (2): 259-272. Butcher, A. and I. Brown (1995). Age-structure, growth and of stout whiting Sillago robusta 1994/95−1995/96

0.15 n = 4922 and Japanese market trials. Final Report to the Fisheries Research and Development Corporation. FRDC 92/101. Deception Bay, Queensland

0.10 Department of Primary Industries. Hyndes, G.A. and I.C. Potter (1996). Comparisons Proportion between the age structures, growth and 0.05 reproductive biology of two co-occurring sillaginids, Sillago robusta and S. bassensis, in temperate coastal waters of Australia. Journal of Fish Biology 49 (1): 0.00 14-32. 0 10 20 30 40 FL (cm) Hyndes, G.A., M.E. Platell and I.C. Potter (1997). Relationships between diet and body size, mouth The length distribution of stout whiting caught during morphology, habitat and movements of six trawl surveys by the Fisheries Research Vessel Kapala was sillaginid species in coastal waters: Implications for comprised mainly of fish between 10 and 20 cm FL. resource partitioning. 128 (4): 585- 598. Queensland Fisheries. (2010). Stock status of Queensland’s fisheries resources 2009-10. Queensland, Department of Employment, Economic 2000/01 Development and Innovation: 65 pp. 0.15 n = 2780

Please visit the CSIRO website, 0.10 http://www.marine.csiro.au/caab/ and search for the species code (CAAB) 37 330005, common name or Proportion scientific name to find further information. 0.05 0.00

5 10 15 20 25 FL (cm)

The length distribution of stout whiting from NSW commercial landings in 2000/01 was comprised mainly of fish between 10 and 20 cm fork length (FL). There is no minimum legal length for stout whiting in NSW.

© State of New South Wales through Industry and Investment NSW 2010. You may copy, distribute and otherwise freely deal with this publication for any purpose, provided that you attribute Industry and Investment NSW as the owner.

Disclaimer: The information contained in this publication is based on knowledge and understanding at the time of writing (April 2010). However, because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check currency of the information with the appropriate officer of Industry and Investment NSW or the user’s independent adviser.

Stout Whiting | p 325 wild fisheries research program

p 326 | Stout Whiting