Gummy Shark (Mustelus Antarcticus)

I & I NSW Wild Fisheries research Program Gummy Shark (Mustelus antarcticus)

Exploitation Status Fully fished

Predominantly a Commonwealth fishery, exploitation status from Commonwealth stock assessment was adopted.

Scientific name Standard name comment

Mustelus antarcticus gummy shark

Mustelus antarcticus Image © Bernard Yau

Background Gummy sharks are lecithotrophic viviparous in that the young develop internally from eggs. The gummy shark (Mustelus antarcticus) is Large pregnant females have been found to widely distributed in Australian waters, ranging carry as many as 57 pups but the smaller NSW from northern NSW around the southern females mostly have between 5 and 10 young. coast, (including Tasmania) to Geraldton in The pups are born in early summer at a size of WA. Gummy sharks are demersal and mainly around 30-35 cm and, although gestation lasts found in continental shelf depths between 20 11-12 months, most females breed only once and 150 m; off NSW they have been recorded every two years. as deep as 450 m. Recent genetic and tagging studies determined that the NSW population The main fishery for gummy sharks is by the was distinct from gummy sharks found along Commonwealth Southern and Eastern Scalefish the southern Australian coast, although some and Shark Fishery (SESSF) in Bass Strait and off overlap occurred off southern NSW. SA where there is an annual allowable catch of about 1800 t. The NSW catch is mostly less Female gummy sharks in southern Australian than 50 t per year and is mainly taken on the waters grow to at least 185 cm total length (TL) south coast by the Ocean Trap and Line Fishery; and 25 kg in weight while males reach almost the remainder is byproduct of the Ocean Trawl 150 cm and 15 kg. In contrast, gummy sharks Fishery. Gummy shark production in the SESSF off central and northern NSW rarely exceed is closely monitored but the relatively small 100 cm in length. The difference in the size production off NSW has not warranted targeted structures of the two stocks is shown by their research. sizes at maturity. About 50% of gummy sharks off southern Australia are mature when they are 110-120 cm in length whereas the length at 50% maturity for NSW sharks is 65-70 cm TL.

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Additional Notes Landings by Commercial Fishery of Gummy Shark • The Commonwealth has completed extensive Ocean Trap and Line (Primary Species) and detailed assessments of this species. The Ocean Prawn Trawl species is not considered overfished and there Fish Trawl are no current concerns about the species in Australian waters. 60 • Relatively easily identified by commercial fishers. 50

• NSW commercial landings are relatively stable 40

at 30 to 50 t per annum. Most (~90%) of the 30 Landings (t) NSW catch is harvested south of Jervis Bay. 20 10 Catch 0 Recreational Catch of Gummy Shark 97/98 99/00 01/02 03/04 05/06 07/08 Financial Year The annual recreational harvest of gummy shark in NSW is likely to be less than 10 t. Reported landings of gummy shark by NSW commercial fisheries from 1997/98. Fisheries which contribute less This estimate is based upon the results of the than 2.5% of the landings are excluded for clarity and offshore recreational trailer boat survey privacy. (Steffeet al. 1996) and onsite surveys undertaken by I & I NSW. Catch Per Unit Effort Information of Gummy Shark Harvested by All Line Fishing Methods in NSW 1.0 Historical Landings of Gummy Shark 0.8 70 0.6 60 0.4 50 Relative Catch Rate 40 0.2 30 Landings (t) 0.0 20 98/99 00/01 02/03 04/05 06/07 08/09 Financial Year 10 Catch rates of gummy shark harvested using all line 0 fishing methods for NSW. Two indicators are provided: 90/91 92/93 94/95 96/97 98/99 00/01 02/03 04/05 06/07 08/09 (1) median catch rate (lower solid line); and (2) 90th Financial Year percentile of the catch rate (upper dashed line). Note that catch rates are not a robust indicator of abundance in Commercial landings (including available historical many cases. Caution should be applied when interpreting records) of gummy shark for NSW from 1990/91 to these results. 2008/09 for all fishing methods.

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Further Reading Gardner, M.G. and R.D. Ward (1998). Population Wilson, D., R. Curtotti, G. Begg and K. Phillips, Eds. structure of the Australian gummy shark (Mustelus (2009). Fishery Status Reports 2008: status of fish antarcticus Gunther) inferred from allozymes, stocks and fisheries managed by the Australian mitochondrial DNA and vertebrae counts. Marine Government. Canberra, Bureau of Rural Sciences and Freshwater Research 49 (7): 733-745. & Australian Bureau of Agricultural and Resource Economics. Henry, G.W. and J.M. Lyle (2003). The National Recreational and Indigenous Fishing Survey. Final Xiao, Y.S. and T.I. Walker (2000). Demographic analysis Report to the Fisheries Research & Development of gummy shark (Mustelus antarcticus) and school Corporation and the Fisheries Action Program. FRDC shark (Galeorhinus galeus) off southern Australia by Project 1999/158. NSW Fisheries Final Report Series applying a generalized Lotka equation and its dual 48. Cronulla, NSW Fisheries: 188 pp. equation. Canadian Journal of Fisheries and Aquatic Sciences 57 (1): 214-222. Last, P.R. and J.D. Stevens (2009). Sharks and Rays of Australia 2nd Edition. Melbourne, CSIRO. Lenanton, R.C.J., D.I. Heald, M. Platell, M. Cliff and J. Please visit the CSIRO website, Shaw (1990). Aspects of the reproductive biology http://www.marine.csiro.au/caab/ and search for the of the gummy shark, Mustelus antarcticus Gunther, species code (CAAB) 37 017001, common name or from waters off the south coast of Western Australia. scientific name to find further information. Australian Journal of Marine and Freshwater Research 41 (6): 807-822. Punt, A.E., T.I. Walker and J.D. Prince (2002). Assessing the management-related benefits of fixed-station fishery-independent surveys in Australia’s Southern Shark Fishery. Fisheries Research 55 (1-3): 281-295. Steffe, S., J. Murphy, D. Chapman, B.E. Tarlington, G.N.G. Gordon and A. Grinberg (1996). An assessment of the impact of offshore recreational fishing in New South Wales on the management of commercial fisheries. FRDC Project 94/053. Final report to Fisheries Research and Development Corporation. Sydney, NSW Fisheries Research Institute: 139 pp. Troynikov, V.S. and T.I. Walker (1999). Vertebral size- at-age heterogeneity in gummy shark harvested off southern Australia.Journal of Fish Biology 54 (4): 863-877. Walker, T.I. (1998). Can shark resources be harvested sustainably? A question revisited with a review, of shark fisheries.Marine and Freshwater Research 49 (7): 553-572. Walker, T.I. (2007). Spatial and temporal variation in the reproductive biology of gummy shark Mustelus antarcticus (Chondrichthyes : Triakidae) harvested off southern Australia.Marine and Freshwater Research 58 (1): 67-97.

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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.

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