TUNA, SOUTHERN BLUEFIN
The Southern Bluefin Tuna is similar to the Pacific Bluefin Tuna. At up to 2.5 metres (8.2 ft) and weighing up to 260 kilograms (570 lb), it is among the larger bony fishes. The Southern Bluefin Tuna is a large, streamlined and fast swimming fish. Southern bluefin tuna, like other pelagic tuna species, are part of a group of bony fishes that can maintain their body core temperature up to 10 degrees above the ambient temperature. This advantage enables them to maintain high metabolic output for predation and migrating large distances. The southern bluefin tuna is an opportunistic feeder, preying on a wide variety of fish, crustaceans, cephalopods, salps, and other marine animals. The Southern Bluefin Tuna is a predatory organism with a high metabolic need. These are pelagic animals, but migrate vertically through the water column, up to 2500 m in depth. They also migrate between tropical and cool temperate waters in the search for food.
Much stockier fish than its name sake the "Northern Bluefin Tuna". Quite cylindrical with short fins. Dark Blue to almost blue-green on the top of its back and silver below. Edges of the fins are yellow, but not as bright as the Yellowfin Tuna. Common around the 12-30 kgs but can grow as large as 160 kgs
Mostly taken on trolled lures, including minnow such as Halco Laser Pros, skirted marlin type lures, feathers and jigs. Usually game fisherman troll around the 6-7 knots. Quite a bit has been written about the resurgence of very large Southern Bluefin in the last couple of seasons (2008/2009), and it seems the species has started to recover from over fishing
The Southern Bluefin Tuna is found in the south-west and south-east Atlantic Ocean, eastern and western Indian Ocean and the south-west Pacific Ocean.
Adult Southern Bluefin Tuna in Australian waters, ranges widely from northern Western Australia to the southern region of the continent, including Tasmania, and to northern New South Wales, appearing in eastern Australian waters mainly during winter. Juveniles of one to two years of age inhabit inshore waters in Western Australia and South Australia.