The Great Australian Bight, off the southern coastline of mainland Australia, is the seasonal home of the Southern Bluefin Tuna.
Prized by Japanese and international restaurants alike, these incredible fish are the cornerstone of one of South Australia’s most famous industries – the Port Lincoln tuna industry.
The sheer volume of Southern Bluefin Tuna in the waters off Port Lincoln became of real interest in the 1940s and 1950s, after the South Australian Government initiated a survey of tuna fish stocks.
Croatian immigrants, who had arrived in Australia post World War 2, understood the economic value of the species and led the expansion of the Port Lincoln tuna industry. Within a decade, nearly 8,000 tonnes of Southern Bluefin Tuna were being caught using the line and pole method.
The next 20 years saw drastic changes to fishing efficiency: line and pole fishing shifted to purse seine methods; chumming boats were introduced; and spotter planes located schools of Southern Bluefin Tuna from the air. By 1982, the levels of Southern Bluefin Tuna catch had reached unprecedented (and unsustainable) levels. Despite warnings from biologists, this overfishing continued and led to disastrous consequences.
A Federal Government inquiry into the tuna industry found that the Southern Bluefin Tuna had been over-exploited and numbers had declined at an alarming rate. In order to protect the species, change was needed… and quickly.
In the hopes of preventing further decline and allowing the Southern Bluefin Tuna time to recover, the Federal Government introduced Individual Transferable Quotas (ITQs) in 1984.
The proceeding years saw drastic reductions in Southern Bluefin Tuna catch and in 1994 the Convention for the Conservation of Southern Bluefin Tuna (CCSBT) was signed.
According to the Australian Southern Bluefin Tuna Industry Association (ASBTIA),
“The introduction of ITQs proved to be very effective in recovering the species biomass. In early September 2014, the CCSBT Scientific Committee confirmed that the latest data indicated a strong recovery of SBT. Today, the spawning biomass has been confirmed to be at a sustainable level, enabling quotas to be increased.”
While the Government restrictions imposed in the 1980s were necessary, they hit the industry hard.
Using the purse seine method, only a select number of fish are transferred to a net, with the remaining fish set free to continue their migration.
The catch is then towed back to Port Lincoln where they are fed a diet of premium, fresh, sustainable sardines. Known as ‘ranching’, this method allows for smaller-sized tuna to grow to a more marketable size, and for fishermen to harvest the fish when they are at their prime.
The method doubled the fishermen’s quota as the limit on their catch was determined by the weight of the fish caught in the wild, with any weight gained in captivity a bonus.
Dinko Lukin’s solution is now the internationally accepted method for Bluefin Tuna farming and has been an incredible success story for the Port Lincoln tuna industry.
The introduction of ranching has allowed the industry to expand significantly, encouraging economic growth and employment opportunities in the region.
“At the time it was first proposed, many experts in the area said that ranching wild SBT would be impossible. However, against all odds and through years of trial and error, Port Lincoln tuna ranching is one of the most successful aquaculture sectors.” ASBTIA