Common Jack Mackerel (Trachurus Declivis) Exploitation Status Uncertain
I & I NSW Wild Fisheries research Program Common Jack Mackerel (Trachurus declivis) Exploitation Status uncertain
Predominantly a Commonwealth fishery with very few operators - Commonwealth status has been adopted.
Scientific name Standard name comment Trachurus declivis common jack mackerel Also known as cowanyoung.
Trachurus declivis Image © Bernard Yau
The common jack mackerel feeds during the Background day primarily on planktonic crustaceans. Jack The common jack mackerel or cowanyoung mackerel in deeper offshore waters include (Trachurus declivis) is found in coastal waters of light fish (Sternoptychidae) and lantern fish southern Australia from Wide Bay, Queensland (Myctophidae) in their diet. The jack mackerel is, to Shark Bay, WA, including Tasmania. It is a in turn, preyed upon by large fish such as tuna, member of the trevally family (Carangidae) barracouta and gemfish. as opposed to most mackerels which belong Individuals grow to at least 64 cm in length with the tunas in the family Scombridae. It is (1.6 kg in weight) and 25 years of age. The very similar and closely related to the common common jack mackerel matures between yellowtail scad (T. novaezelandiae) and the larger 3 and 4 years old at a length of about 27 cm Peruvian jack mackerel (T. murphyi) which is and a weight of 250 g. Spawning in NSW occurs occasionally found among jack mackerel catches between October and January in waters above off southern Australia. the thermocline. After spawning, the eggs and There are three jack mackerel subpopulations larvae travel on currents into inshore waters in Australian waters: one in the Great Australian where most juveniles remain during early Bight, another in NSW waters, and the third off growth. Tasmania. They are pelagic, forming schools Despite its schooling behaviour, the common over the continental shelf and outer shelf jack mackerel is seldom targeted in NSW margin. Individuals have been found in depths by commercial fishers as it has poor market of 460 m but this species is more commonly acceptance. The bulk of the catch is caught by found between 20 m and 300 m. The common purse-seine (Ocean Hauling fishery) with small jack mackerel shows a preference for water quantities landed by trawlers; most is sold for temperatures less than 17°C and entire schools aquaculture feed or bait. will move to stay below this temperature. Large schools of jack mackerel regularly appear during This species was the subject of a large fishery off winter-spring in surface waters off southern Tasmania in the 1980s, but recent catches have NSW. been very small. A lack of assessment data has led to the status of the jack mackerel stock being classified as ‘uncertain’.
status of fisheries resources in nsw, 2008/09 Common jack mackerel | p 77 wild fisheries research program
Additional Notes Further Reading
• Not the basis for a significant fishery in NSW. Gomon, M.F., J.C.M. Glover and R.H. Kuiter (1994). The Fishes of Australia’s South Coast. Adelaide, State • There is only a small incidental purse-seine Print. catch in winter off Wollongong. Kailola, P.J., M.J. Williams, P.C. Stewart, R.E. Reichelt, A. McNee and C. Grieve, Eds. (1993). Australian • After very significant landings (up to Fisheries Resources. Canberra, Australia, Bureau 42,000 t in the late 1980s) this is now a very of Resource Sciences, Department of Primary small fishery within the Commonwealth Industries and Energy, and the Fisheries Research ‘Small Pelagics’ fishery (jack mackerel and Development Corporation. landings were around 400 t in 2008/09 (Wilson et al. 2009). Pullen, G. (1994). Fishery status report: purse seine (the Tasmanian jack mackerel fishery). Internal Report No. 13. Hobart, Tasmanian Department of Primary Catch Industries and Fisheries. Recreational Catch of Common Jack Mackerel Webb, B.F. and C.J. Grant (1979). Age and growth The annual recreational harvest of common jack of jack mackerel, Trachurus declivis (Jenyns), from mackerel in NSW is likely to be less than 10 t. south-eastern Australian waters. Australian Journal of Marine and Freshwater Research 30: 1-9. Wilson, D., R. Curtotti, G. Begg and K. Phillips, Eds. (2009). Fishery Status Reports 2008: status of fish stocks and fisheries managed by the Australian Historical Landings of Common Jack Mackerel Government. Canberra, Bureau of Rural Sciences & Australian Bureau of Agricultural and Resource Economics. 800 Yearsley, G.K., P.R. Last and R.D. Ward (1999). Australian Seafood Handbook. Hobart, CSIRO Marine Research. 600
400 Please visit the CSIRO website,
Landings (t) http://www.marine.csiro.au/caab/ and search for the species code (CAAB) 37 337002, common name or 200 scientific name to find further information. 0
88/89 93/94 98/99 03/04 08/09 Financial Year
Commercial landings (including available historical records) of common jack mackerel for NSW from 1984/85 to 2008/09 for all fishing methods.
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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. p 78 | Common jack mackerel