Australia's catch of the southern bluefin tuna will be cut by 30%, following a major international agreement.
The new levels agreed by fishing nations on South Korea's Jeju Island will represent a cut of 20% internationally, the ABC reports.
Australia had pushed for a 50% cut of the total allowable catch, but it is believed the motion was subject to significant opposition by other member countries.
The agreement is in force immediately.
The reduction follows the findings of a secret scientific report which found that the southern bluefin's spawning stock is now at 5% of what it was in the 1940s.
Tuna fishers at Port Lincoln in South Australia, who catch 90% of Australia's tuna, say they are outraged by the big reduction in catch quotas.
Australian Tuna Association chief executive Brian Jeffries says the cut will cause job losses in the region.
Mr Jeffries said New Zealand actually got a quota increase. The ABC reports New Zealand was believed to have effectively lobbied to increase its quota and then sold its increase to Japan.
It is also believed that Japan increased its quota and was not penalised for overfishing the stock over a 20-year period.
Some scientists say the reduction is too small to save the species while others have welcomed it as a start which will at least halt its decline for the time being.