I & I NSW Wild research Program Cobia (Rachycentron canadum)

Exploitation Status UNDEFINED A minor in NSW waters, but significant to recreational fishers. The stock is shared with Queensland where some biological research is underway. Very little useful information currently available from NSW catches. Scientific name Standard name comment

Rachycentron canadum cobia Also known as black kingfish.

Rachycentron canadum Image © Bernard Yau

Background Cobia (Rachycentron canadum) has an almost Cobia grow extremely quickly and can reach world-wide distribution in tropical and sub- more than 75 cm after 3 years, and attain a tropical waters, except in the eastern Pacific maximum length of 1.8 m fork length (FL) and Ocean. In Australian waters, cobia are common weight of about 60 kg, at about 13 years of around the tropical north of the country and age. In Queensland, cobia have a protracted south to south-western Western Australia and spawning season between September and June central NSW. They are a large, wide-ranging but with a peak around October to December. species generally observed as solitary fish; The length at 50% maturity for females is around however they occasionally form small schools 78 cm FL. that associate with floating objects, fixed Cobia are only a minor commercial species; structures and large oceanic animals including however their large size and excellent table sharks, rays, turtles and whales. Cobia are qualities make them a prime recreational often referred to as a pelagic species, although sport and table fish. Their rapid growth rate dietary studies reveal that a large portion of also makes cobia an attractive species for their diet is comprised of benthic and demersal . In NSW, cobia have no minimum prey including crabs, stingrays, flatfishes and legal length and no specific bag limit, but they stomatopods. In Australia, cobia populations are included in the ‘general’ bag limit of 20. In make seasonal migrations over large distances; Queensland cobia have a minimum legal length moving north with migrating whales in winter of 75 cm total length and a bag limit of 2. and returning south in summer.

status of fisheries resources in nsw, 2008/09 COBIA | p 69 research program

Additional Notes Landings by Commercial Fishery of Cobia • A northern species which occurs seasonally off Ocean Trap and Line NSW - the annual commercial catch is less than Ocean Prawn Trawl 10 t and fluctuates from year to year. 6 • Cobia are mainly taken by line , but there is also a small by-catch from prawn trawling. 4 Landings (t) • Queensland commercial fishery is estimated to be 20 to 40 t - the recreational fishery is 2 significant but is not well estimated. 0

97/98 99/00 01/02 03/04 05/06 07/08

Catch Financial Year Recreational Catch of Cobia Reported landings of cobia by NSW commercial fisheries from 1997/98. Fisheries which contribute less than 2.5% The annual recreational harvest of cobia in NSW of the landings are excluded for clarity and privacy. is likely to be less than 20 tonnes. This estimate is based upon the results of the offshore recreational trailer boat survey (Steffeet al. Growth Curve of Cobia 1996) and onsite surveys undertaken by

I & I NSW. 120 100 Historical Landings of Cobia 7 80 6 60 TL (cm) 5 4 40 3 Landings (t) 20 2

0 5 10 15 1 Age (years)

0 Growth curve of cobia using parameters from Fry and

90/91 92/93 94/95 96/97 98/99 00/01 02/03 04/05 06/07 08/09 Griffiths (2010). Lengths are presented as total length Financial Year (TL).

Commercial landings (including available historical records) of cobia for NSW from 1990/91 to 2008/09 for all fishing methods. Further Reading

Franks, J.S., J.R. Warren and M.V. Buchanan (1999). Age and growth of cobia, Rachyc