 Improved refrigeration techniques and a demanding global market saw global SBT catch plummet from 80,000 tonnes a year during the 1960s to 40,000 tonnes a year by 1980.Australian catch peaked in 1982 at 21,500 tonnes, and the total population of SBT has since declined by about 92 percent.There was a pressing obligation to reduce harvesting pressure southern bluefin tuna populations in the mid-1980s.