By PAUL GREENBERG

The world’s largest tuna - the giant Atlantic bluefin - is equipped with a kind of natural GPS system and can cross and recross the Atlantic Ocean multiple times during its life.

Its furious metabolism enables the fish to sprint at more than 65 kilometers an hour and hunt relentlessly at frigid depths in excess of 455 meters. Yet in spite of all of its feral characteristics, scientists have announced an important step toward converting the Atlantic bluefin, in rapid decline in the wild, into a farm animal.

Researchers at a European Union-financed program, Selfdott, said they had succeeded in spawning the Atlantic bluefin in captivity. If they can solve the problem of raising the offspring to adulthood, the bluefin may join Atlantic salmon, rainbow trout, and other fish as an industrially farmed staple of the modern fish market.

Which brings up an interesting question: Can a farmed version of bluefin tuna be better for the earth ? and the species? In the last 50 years, the global seafood market has transformed from one based on wild fish to one in which farming supplies nearly half of the market, according to the United Nations Food and Agriculture Organization.

Leading this transition is wild Atlantic salmon, which collapsed as a commercial species in the 1960s and was subsequently replaced in the marketplace by farmed Atlantic salmon. Atlantic salmon’s availability has not been without repercussions. Farmed salmon are often grown in the pathways of wild salmon migration routes, and many groups have placed farmed salmon on their “do not eat” lists, largely because of the threat that farm-born diseases, waste and parasites may pose to already depressed runs of wild salmon.

But cultivating Atlantic bluefin tuna, environmentalists argue, could be even more harmful to the ocean than salmon farming. Atlantic bluefin are already ranched in great numbers - taken from the wild and fattened in net pens with wild forage fish like herring and sardines. It may take anywhere from 2 kilograms to 6 kilograms of wild fish to grow a single kilogram of Atlantic bluefin.

The Stanford economist Rosamond Naylor addressed the issue in a recent paper in The Proceedings of the National Academy of Sciences. “Most forage fisheries,” Ms. Naylor wrote “are either fully exploited to overexploited or are in the process of recovering from overexploitation.” If she is right ? and if bluefin tuna farming is ramped up to the level of salmon farming, which produces more than 900,000 metric tons a year ? the effect on forage fish, the foundation of the oceanic food chain, could be devastating.

A worldwide overharvest of forage fish could damage other commercial species that also rely on these fish. But alternatives to forage fish are being developed, including feed pellets made from algae and other vegetable matter. Global fishing moratoriums on Atlantic bluefin have been proposed (and rejected by the many nations that catch bluefin).

But other options being discussed include greatly reducing fishing quotas and closing spawning grounds in the Mediterranean and the Gulf of Mexico to fishing entirely. Perhaps, in the end, this is what the Atlantic bluefin tuna might really need. Not human intervention to make them spawn in captivity. But rather human restraint, to allow them to continue spawning in the wild.