A new stock assessment by the International Scientific Committee for Tuna and Tuna-Like Species in the North Pacific Ocean (ISC) concludes that current Pacific bluefin tuna numbers are at near historically low levels and experiencing high commercial overfishing.
According to the report, spawning biomass is down 85 percent from the 1950s. ISC data show a drop of 130,000 metric tons in the 1950s to just over 20,000 metric tons in 2010. One metric ton is equal to about 2,204 pounds. Actual stock declines--including immature, non-spawning fish--are estimated as high as 96 percent, according to PEW, a national environmental group.
There's no doubt about it, bluefin tuna are in high demand, often selling at head-turning prices. A recent 489-pound bluefin tuna, caught off Oma, Japan, sold for $1.76 million in Tokyo. With absurd prices like that, a commercial fisherman could be set for life with just one fish sold.
Pacific bluefin tuna (Thunnus orientalis) is treated as a single Pacific-wide stock found throughout the northern Pacific Ocean, with spawning grounds recognized only in the western North Pacific.
Japan, Korea, Taiwan, the United States, and Mexico catch the largest numbers of Pacific bluefins.
The majority of Pacific bluefin tuna are caught in purse seine fisheries, though nets, trolling, longlines and other fishing methods are used. Historical catches were predominately comprised of juvenile bluefins, but since the early 1990s catching immature, young-of-the-year fish has increased significantly.
Atlantic bluefin stocks may be fairing slightly better, and there are even pilot programs aimed at reducing unintentional bycatch of bluefin tuna in the Gulf of Mexico using "greenstick" and swordfish buoy gear.