![]() Like wolves, bluefins often hunt in packs, forming a high-speed parabola that concentrates the prey, making it easier for the hunters to close in. “The more sophisticated our robotic-tuna designs become,” the Triantafyllou brothers wrote, “the more admiration we have for the flesh-and-blood model.” The researchers found that the tail’s efficiency lay in the interaction of the vortices created by its rapid flexing, but the hydrodynamics of their electronic models did not even come close to that of a true bluefin. It is such a marvelous swimmer that when scientists in the 1990s endeavored to build a mechanical fish, they used the species as a model, designing a robot with a tapered, bullet-shaped body and a rigid, quarter-moon tail fin. The bluefin is also among the fastest of all fishes, capable of speeds up to 80 kilometers per hour and able to migrate across entire oceans. During a dive to one kilometer below the surface, where the ambient water temperature can be five degrees Celsius (41 degrees Fahrenheit), the bluefin can maintain a body temperature of 27 degrees C (81 degrees F), close to that of a mammal. Whereas most of the approximately 20,000 fish species are cold-blooded, possessing a body temperature the same as that of the water in which they swim, the bluefin is one of the few warm-blooded fishes. Reaching a maximum known weight close to three quarters of a ton and a length of four meters, the bluefin is a massive hunk of superheated muscle that cleaves the water by flicking its scimitar-shaped tail. Heedless overfishing is steadily pushing the bluefin toward extinction, and the species may soon disappear unless entrepreneurial fish farmers can learn how to breed the tuna in captivity. As such, it has vaulted to the top of another, more insidious list: it is probably the most endangered of all large fish species. But the bluefin tuna, a giant among fishes, is the premier choice for sushi and sashimi and has become the most desirable food fish in the world. The canned tuna fish in sandwiches and salads comes from either skipjack, a meter-long species that is caught in prodigious quantities around the world and served as “light meat tuna,” or albacore, another small fish that is marketed as “white meat tuna.” The yellowfin and the bigeye tuna are larger species that are also heavily fished, but neither makes for particularly wonderful sushi, and they are usually served grilled. Bluefin tuna can cross the Atlantic in less than 60 days.Editor's Note: This story was originally printed in the March 2008 issue of Scientific American.Īll tuna are not alike. In the western Atlantic Ocean, fishermen find bluefin tuna from Labrador, Canada to northern Brazil. Bluefin tuna live in both subtropic and temperate waters.Yet strict regulations allow for a limited number of bluefin tuna caught by accident to be kept. Commercial fishermen are not allowed to use longlines to target bluefin tuna. Since the late 1940s, Massachusetts has been one of the top states for commercial landings of bluefin tuna.Yet the second half of the century saw stock reductions in bluefin tuna, prompting management measures. Atlantic bluefin tuna was not a target species on the United States east coast early in the 20th century.They have been spotted from the ocean's surface to more than 3,000 feet below. They get close to the shore depending on the season. This means they must keep moving to stay alive. Atlantic bluefin tuna are ram ventilators.The schools can consist of other species like yellowfin, bonito, and skipjack tunas. Once between 90 and 130 pounds, bluefin tuna split into schools based on size. The eggs travel along the currents and hatch when they are about a foot long. Females can produce up to 25 million eggs per year, depending on the female's size. Atlantic bluefin tuna reach maturity at about three years when in human care.They have spawned in two known areas of the Atlantic, the Mediterranean and the Gulf of Mexico. We know little about where bluefin tuna tend to give birth. ![]() Seabirds tend to feed on young bluefin tuna. On the other end, sharks and whales prey on bluefin tuna. When those species are absent, bluefin tuna will eat whatever they come across. ![]()
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