Southern Bluefin Tuna
Introduction
Found in the Southern Hemisphere, Southern Bluefin Tuna are a large and fast-swimming pelagic (ocean going) fish. Southern Bluefin Tuna exist largely in the world’s southern oceans and congregate in the costal waters off southern Australia.
They spawn between September and April each year in the only known spawning grounds in the Indian Ocean, between the north-west Coast of Australia and Indonesia. The eggs are estimated to hatch within two to three days.
At approximately 20 days, the Southern Bluefin Tuna larvae become fingerlings, which feast on a wide range of food, including fish larvae and juvenile fish.
Southern Bluefin Tuna usually reach approximately 15 kilograms over the next two years and this size is the principal wild catch of the Australian Southern Bluefin Tuna industry.
Cleanseas believes that Southern Bluefin Tuna become sexually mature between 9 and 12 years of age in the wild.
History of Southern Bluefin Tuna Catch
The population has decreased over the past 50 years due to the increasing demand from overseas markets. Improved refrigeration techniques in the mid 1960’s paved the way for the transportation of fresh Southern Bluefin Tuna across the world.
Until the late 1960’s, the majority of Australian Southern Bluefin Tuna were either caught in the Eden/Ulladulla region of New South Wales or in Port Lincoln, South Australia. During the 1970’s almost all of the Southern Bluefin Tuna fishing companies moved permanently to Port Lincoln.
The world Southern Bluefin Tuna catch was approximately 80,000 tonnes per year in the early 1960’s – and by the mid 1960’s it had plummeted to 60,000 tonnes. During 1980, the catch had declined even further to 40,000 tonnes a year.
This sharp decline was soon recognised by the fishing countries of Japan, Australia and New Zealand, and a voluntary catch quota was enforced.
Despite these protective measures, numbers still continued to decline and in 1989 the three countries reduced the quotas even further to their current levels of 11,750 tonnes between them.
The arrangement between the countries was formalised in 1994, when the Commission for the Conservation of Southern Bluefin Tuna (CCSBT) was formed.
The current quota for CCSBT members are14,030 tonnes per year of Southern Bluefin Tuna.
Current Southern Bluefin Tuna Production
Juvenile Southern Bluefin Tuna fish weigh an average of 15 Kilograms and are caught from December to April each year. The Southern Bluefin Tuna are then “grown-out” in sea pontoon cages for three to eight months, reaching an average of 30 to 40 kilograms. The fish are then exported either fresh or frozen to Japan. With the future propagation of Southern Bluefin Tuna at its Arno Bay hatchery, Cleanseas is poised to capitalise on many lucrative international markets through its specialised aquaculture endeavour. The successful closing of the Southern Bluefin Tuna life cycle by Cleanseas will produce unrestricted additional tonnages of this valuable fish; supplying the growing global demand for Southern Bluefin Tuna and other high quality aquaculture based products.
Australian Supply of Southern Bluefin Tuna
The majority of Australia’s Southern Bluefin Tuna quota is farmed in waters off Port Lincoln. Boasting a farm gate value of $242 million, the total weight of Port Lincoln tuna farmed output increased to 9,290 tonnes of tuna in 2003-2004.
The Hatchery
State-of-the-art, world-class and innovative – Cleanseas’ Arno Bay hatchery impresses all who have passed through its doors. Cleanseas acquired the hatchery in November, 2000 and undertook a $2.5 million upgrade.
During this process Kingfish and Mulloway broodstock facilities were constructed, along with a live-feed production plant. The hatchery is staffed by highly trained technicians all with a great passion to succeed.
What Next?
Cleanseas is confident of the future potential for the aquaculture industry across the world. This view is evident by:
- Global decline in the wild catch supply
- Growth of aquaculture-bred fish throughout the world
- Shift in the value of healthy eating habits and the role fish plays in a balanced diet.
