Longlining, Overfishing & Atlantic Bluefin Tuna

By: Qinyan Huang

From PBS Marine Fisheries and Aquaculture, I was informed that the Bluefin Tuna populations in the Atlantic Ocean have declined over 70% in the last 30 years and that it has become a threatened fish which is on the brink of extinction.

Bluefin Tuna contains high protein, omega-3 and omega-6, while low in fat and sodium, which means it is an excellent food source of essential fatty acids, which is very critical for health and disease prevention. Thus, Bluefin Tuna is one of best-selling fish around the world, especially for sushi aficionados. Due to the growing demands for Bluefin Tuna, it is over-fished to the point of extinction.

Bluefin Tuna is a highly migratory species that requires high levels of international cooperation for appropriate management and conservation. The United States is responsible for about only 2% of the global Bluefin Tuna catch. In U.S. fisheries, Bluefin Tuna are caught with purse seines, hand gears and longlines. Pelagic longline gear is not allowed to directly target Bluefin Tuna but is allowed to retain a limited amount of Bluefin Tuna caught incidentally while targeting other species, such as swordfish, yellowfin tuna, and bigeye tuna. Thus, habitat damaged by highly migratory species fishing gear, other than bottom longlines, is minor because the gear rarely comes in contact with the ocean floor.

However, in Japan, Pelagic longline gear is allowed to directly target Bluefin Tuna, and bottom longlines is widely used in local water. Higher operation cost, lower profit margins and stricter quotas in other parts of the world have created an irresistible urge for Japanese boats to take more Bluefin from their own waters. Furthermore, Japanese fisheries have no idea how many Bluefin Tuna they are catching or what size they are, and the prized Bluefin Tuna will soon fade away from Japanese restaurants’ obsession menu.


Source:
PBS Marine Fisheries and Aquaculture, http://www.pbs.org/emptyoceans/eoen/tuna/ casestudy.html
The Guardian http://www.guardian.co.uk/environment/2008/nov/18/fishing-japan -conservation-tuna