I & I NSW WILD FISHERIES RESEARCH PROGRAM Mackerel Tuna (Euthynnus affinis) EXPLOITATION STATUS UNDEFINED Small commercial fishery with low priority for assessment. Possibly more significant in the recreational fishery. Minimal information available. SCIENTIFIC NAME STANDARD NAME COMMENT Euthynnus affinis mackerel tuna Euthynnus affinis Image © Bernard Yau Background The mackerel tuna (Euthynnus affinis), also patterns by the spots and, in the case of frigate known as the little tuna, belongs to the family mackerel, the lack of space between the dorsal Scombridae which includes the mackerels, fins. Mackerel tuna can grow to 100 cm fork tunas and bonitos. It is a widespread pelagic length (FL) and about 20 kg in weight but species found in the tropical waters of the are more commonly around 60 cm and 3 kg. Indo-Pacific. Although also inhabiting ocean They feed on small fish, particularly clupeids waters, mackerel tuna prefer to stay close to the (herrings, pilchards) and silversides, as well as coast and juveniles are even found in bays and on squids, crustaceans and zooplankton. Their harbours. It is a highly migratory species and predators include billfish and sharks. frequently forms large schools which are often In NSW and Queensland, mackerel tuna are mixed with other scombrid species. In Australia, usually caught on lines by fishers targeting mackerel tuna range from Cape Leeuwin, WA, mackerel (Scomberomorus spp.) and larger around northern Australia and Queensland to tunas. Annually, 10-20 t of mackerel tuna are the south coast of NSW. landed for sale in NSW with almost all the catch Mackerel tuna is a small tuna with a distinctive taken by the Ocean Trap and Line Fishery. dark-striped pattern on its back and 2-5 However, it has dark flesh which deteriorates dark spots above the ventral fin. It can be quickly resulting in poor marketability. distinguished from similar species with striped Despite this, mackerel tuna are popular with recreational fishers as a light-tackle gamefish. STATUS OF FISHERIES RESOURCES IN NSW, 2008/09 MacKEREL TUNA | P 195 WILD FISHERIES RESEARCH PROGRAM Additional Notes Landings by Commercial Fishery of Mackerel Tuna • A highly migratory small tuna species that Ocean Trap and Line occurs throughout the Indo-West Pacific region - NSW is at the southern extremity of 30 its range. 25 • There is minimal information available on this species from fisheries in NSW waters. 20 • Commercial landings are low (10 to 20 t 15 recently). Landings (t) 10 • Species may be significant in recreational catches, but accurate catch estimates are not 5 available. 0 97/98 99/00 01/02 03/04 05/06 07/08 Financial Year Catch Reported landings of mackerel tuna by NSW commercial fisheries from 1997/98. Fisheries which contribute less Recreational Catch of Mackerel Tuna than 2.5% of the landings are excluded for clarity and privacy. The annual recreational harvest of mackerel tuna in NSW is likely to be less than 50 t. This estimate is based upon the results of the offsite Further Reading National Recreational and Indigenous Fishing Collette, B.B. and C.E. Nauen (1983). Scombrids of the Survey (Henry and Lyle, 2003) and onsite World. An Annotated and Illustrated Catalogue surveys undertaken by I & I NSW. of Tunas, Mackerels, Bonitos and Related Species Known to Date. Rome, FAO: 137 pp. Griffiths, S.P., P.M. Kuhnert, G.F. Fry and F.J. Manson (2009). Temporal and size-related variation in the Historical Landings of Mackerel Tuna diet, consumption rate, and daily ration of mackerel tuna (Euthynnus affinis) in neritic waters of eastern 40 Australia. Ices Journal of Marine Science 66 (4): 720- 733. Henry, G.W. and J.M. Lyle (2003). The National 30 Recreational and Indigenous Fishing Survey. Final Report to the Fisheries Research & Development 20 Corporation and the Fisheries Action Program Project FRDC 1999/158. NSW Fisheries Final Report Landings (t) Series No. 48. 188 pp. Cronulla, NSW Fisheries. 10 Hutchins, B. and R. Swainston (1999). Sea Fishes of Southern Australia - Complete Field Guide for Anglers and Divers. Smithfield, NSW, Gary Allen Pty 0 Ltd. 90/91 92/93 94/95 96/97 98/99 00/01 02/03 04/05 06/07 08/09 Financial Year Kuiter, R.H. (1993). Coastal Fishes of South-Eastern Australia. Honolulu, University of Hawaii press. Commercial landings (including available historical records) of mackerel tuna for NSW from 1990/91 to Yearsley, G.K., P.R. Last and R.D. Ward (1999). Australian 2008/09 for all fishing methods. Seafood Handbook. Hobart, CSIRO Marine Research. Please visit the CSIRO website, http://www.marine.csiro.au/caab/ and search for the species code (CAAB) 37 441010, common name or scientific name to find further information. © 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. P 196 | MacKEREL TUNA.