Tuna: Bluefin, Southern

Atun de aleta azul, Horse mackerel

Kuromaguro, Honmaguro, Toro

There are three species of bluefin tuna: Southern, Atlantic, and Pacific.

Atlantic and Pacific bluefin are found in the northern waters of their respective oceans, while southern bluefin tuna are found in the southern waters of the Atlantic and Pacific Oceans, as well as in the Indian Ocean.

Bluefin tuna are highly migratory, crossing international borders along their migrations, and are targeted in various fisheries worldwide with a number of different gear types: purse seines, pelagic longlines, trolls, handlines, pole and line gear, and harpoons. Each of these gear types results in different levels of bycatch and habitat effects. Bycatch of threatened sea turtles, seabirds, sharks and billfish is of particular concern. Overall, bluefin tuna is ranked as moderately vulnerable to fishing pressure. Status of the stocks is also of serious concern for all species.

The combination of high to critical bycatch concerns, poor management and poor stock conditions results in an overall recommendation of “Avoid” for all three species of bluefin tuna.

Southern bluefin tuna have limited distribution (in comparison to other tunas), fidelity to particular spawning grounds, and are slow to mature. These traits make southern bluefin tuna moderately vulnerable to fishing pressure.

The southern bluefin tuna is in recognized decline throughout its range. An outdated stock assessment (1998) shows spawning biomass in decline, and recruitment at approximately 1/3 of the 1970 level. Unreported fishing by nations not a members of the Convention for the Conservation of Southern Bluefin Tuna (CCSBT) has resulted in a slow recovery of this species. According to Australia’s Bureau of Rural Sciences, the southern bluefin is fished at 30% above the total allowable catch limits set by the CCSBT.

Longlining is a preferred method to catch southern bluefin tuna. Monitoring of this fleet is sparse to non-existent. Pelagic longlines are known to capture several species of turtles and seabirds, many of which are endangered.

Pelagic longlining has no direct habitat impact, however, the potential ecosystem effects of removing these large predators from the world’s oceans and the bycatch of vulnerable and threatened species have been identified as two environmental risks associated with the increased pressure by tuna fisheries.

Although regional management of southern bluefin tuna is attempted through the Convention for the Conservation of Southern Bluefin Tuna, there has been an increase in unreported catch by non-member nations. Anticipated benefits of the Convention have not been realized due to illegal fishing. The Convention itself has provisions for monitoring and setting catch quotas, however, overall this species is poorly managed due to illegal fishing and is a high conservation concern.

What kind of tuna is this?

Bluefin tuna should be avoided

Elevated mercury and PCB levels + Men should limit intake to less than 1/2 a meal per month + Women and kids under 12 should not eat at all

No.