© Richard Herrmann / Seapics.comBluefin tuna.
Populations of bluefin tuna in the western Pacific Ocean are
down by nearly 97 percent from pre-fishing levels, according to a stock assessment by researchers.
"We found the Pacific bluefin stock is being overfished," said Steve Teo, a fisheries biologist at the Southwest Fisheries Science Center in La Jolla, Calif., who was involved in the assessment.
The news comes a few days after an enormous, 489-pound (222-kilogram) tuna fetched $1.76 million at a Japanese auction,
the Associated Press reported. Strong demand for tuna, primarily for
use in sushi, has driven increased harvesting of the fish. Over the past 15 years, its population in the western Pacific has steadily declined and is now at or near an all-time low, Teo told LiveScience.
There are currently no catch limits for tuna in the western Pacific. About 90 percent of the fish that are caught are juveniles, according to the stock assessment.
Amanda Nickson, director of global tuna conservation for the Pew Environment Group, called for a temporary halt to fishing. "We think the most responsible thing to do is to suspend the fishery until we can put measures in place that will ensure that the population decline is reversed," Nickson said.
She called on the governments of the countries that harvest the fish - including Japan, Taiwan, South Korea, Mexico and the United States - to do something about the tuna's plummeting numbers.
