Ranch farming and Japanese sashimi brings Port Lincoln tuna industry back in a big way in the 1990s
Port Lincoln fisher Dinko Lukin introduced tow pontoons (top), allowing the southern bluefin tuna to be purse seined (netted) in larger numbers. Bottom: Japanese sashimi market in the 1990s became the destination for 95% of Australia's tuna.
Southern bluefin tuna ranching became a momentous success story for Port Lincoln on South Australia’s Eyre Peninsula, in response to severe fishing quota cutbacks in the 1980s to save the species.
Japanese interests initially proposed ranching southern bluefin tuna, to grow the smaller fish migrating past Port Lincoln to a marketable size. Many experts said that ranching wild southern bluefin tuna was impossible.
Northern bluefin tuna (Thunnus orientalis) were ranched on a small scale in Japan, but from 400 grams, with more than 90% dying. Other countries tried ranching other tuna species but the fish were easily spooked in closed environments, damaging themselves and the pontoons. Southern bluefin tuna can swim at up to 70km/h and grow to 200 kilograms.
A study into ranching was started in 1991 by the Tuna Boat Owners Association of Australia and the Federation of Japan Tuna Fisheries Co-operative Associations with the Overseas Fishery Cooperation Foundation. The project, supported by the South Australian and Australian governments, was by the industry with the fisheries research and development corporation led by Brian Jeffriess, with Patrick Hone.
Southern bluefin tuna proved more amenable to being ranched than some other species, and the young fish, two to four years old, could be quickly fattened to a size suited to the Japanese sashimi markets. On the basis of the study, the Port Lincoln industry began to capture tuna by poling individual fish into the wells of their vessels, and transporting them to pontoons in Boston Bay.
Port Lincoln fisher Dinko Lukin introduced tow pontoons, allowing the southern bluefin tuna to be purse seined (netted) in larger numbers. The towing pontoons greatly reduced fish mortality compared with previous capture and transfer. The fish are towed from the point of capture, at about one knot, into the ranching pens, over two weeks. The pens were originally in Boston Bay but a major storm in the Port Lincoln area in 1996 wiped out the tuna stocks ranched there and the industry moved to deeper water in the lower part of the Spencer Gulf.
Southern bluefin tune is caught in the Great Australian Bight over summer, feedlotted in tuna pens, and then harvested in July and August mainly for Japan.
Although Australia wasn’t able to effectively tap into the Japanese sashimi market until the 1990s, it became the destination for 95% of Australia's southern bluefin tuna.
The ranching grew to 12 companies having southern bluefin tuna in about 100 pontoons in Lincoln offshore aquaculture zone (inner/outer sectors). The ranching industry steadily expanded to produce up to 9,000 tonnes of gilled and gutted southern bluefin tuna annually, valued between $150 and $300 million.