bluefin

As chefs at the upscale New York sushi restaurant Megu slide huge knives through their latest bluefin tuna, the possible extinction of the species is far from their minds.

With effective trade restrictions, bluefins could return to historic levels in a surprisingly short period of time, after which they could be harvested at sustainable levels.

"The mixing may have caused people to overestimate the abundance of western bluefins," comments John Magnuson of the University of Wisconsin-Madison.

To get more specific information on where the tuna spend time, Jay Rooker of Texas A&M University at Galveston set out to identify the origins of fish by examining the chemicals of their otoliths, or "ear stones." Nearly 200 Atlantic bluefins, from both sides of the ocean, were tracked over a six-year period.

The fishery declined as market fishing for bluefins exploded and purse seines and longlines began taking their toll.

To better understand the fish, Block and her colleagues worked with sports and commercial fishers in 1996 to tag 377 bluefins in the western Atlantic.

The Bahamas bluefin fishery is not as healthy these days, but there is general consensus that the fishery is slowly rebounding.

Current regulations treat bluefin tuna in the western and eastern regions of the Atlantic as separate populations.

Their object: to locate schools of bluefin tuna, 500- to 700-pound fish that are highly prized by commercial fishermen.