30 Days of OCEANS: Richard Ellis

May 3, 2010

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One of the most prominent writers on ocean issues, Richard Ellis is also a pre-eminent wildlife painter. A research associate at New York’s American Museum of Natural, his book “Tuna, A Love Story,” is the definitive take on the health of one of the world’s most elegant – and endangered – fish. This “quintessential ocean ranger, the wildest, fastest, most powerful fish in the sea” may be gone from the oceans as soon as 2012. An excerpt from OCEANS, The Threats To Our Seas and What You Can Do to Turn the Tide.

The canned substance in tuna fish sandwiches and salads is either skipjack, a three-foot-long tuna species that is caught in prodigious quantities around the world and served as “light-meat tuna;” or albacore, another small tuna that is marketed as “white-meat tuna.” A couple of larger species of tuna that are also heavily fished are the yellowfin and the bigeye tuna, but neither of these makes for particularly desirable sushi, and they are usually served grilled. The bluefin tuna, a giant among fishes, is the fish of choice for sashimi, and has become the most desirable food fish in the world, and as such, has vaulted to the top of another, more insidious list: It is probably the most endangered of all large fish species.

Reaching a maximum known weight close to three-quarters of a ton and a length of twelve feet, the bluefin is a massive hunk of superheated muscle that cleaves the water by flicking its scimitar-shaped tail. It is one of the fastest of all fishes, capable of speeds up to fifty-five miles per hour; able to migrate across entire oceans. While most of the 20,000-odd species of fishes are “cold-blooded,” with a body temperature the same as the water they swim in, the bluefin is one of the few hot-blooded fishes. During a dive to 3,000 feet, where the ambient water temperature can be 40°, the bluefin can maintain a body temperature of 80°, close to that of a mammal. 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. Tuna are metabolically adapted for high-speed chases, but as opportunistic (and by necessity, compulsive) feeders, they will eat whatever presents itself, whether fast-swimming mackerel, bottom-dwelling flounder, or sedentary sponge. A study of the stomach contents of New England bluefins by Bradford Chase revealed that the most popular food item (by weight) was Atlantic herring, followed by sand lance, bluefish, and miscellaneous squid. (In addition to these prey items, Chase also found butterfish, silver hake, windowpanes, winter flounder, menhaden, sea horses, cod, flounder, plaice, pollock, filefish, halfbeak, sculpin, spiny dogfish, skate, octopus, shrimp, lobster, argonaut, crab, and sponges.) Tuna will eat anything they can catch, and they can catch almost anything that swims (or floats, crawls, or just sits on the bottom.) By and large, they hunt by vision.

At one time, the bluefin tuna was known as “horse mackerel,” and its red, strong-flavored flesh was considered suitable fare only for dogs and cats. Around the turn of the last century, while still thought of as inedible, the bluefin was targetted by big-game fishermen off New Jersey, and then Nova Scotia, because these powerful fish, reaching a weight of half a ton or more, were considered worthy opponents for fishermen in quest of “sport” and world’s records. Zane Grey was one of the most popular authors of the 1920s, with western novels such as Last of the Plainsmen and Riders of the Purple Sage, but his passion was big-game fishing, and he invested most of his not inconsiderable royalties (his books sold more than 13 million copies) on fishing gear, fishing boats, and travel to exotic locales in search of tuna, swordfish and marlins. Other “sportsmen” wrote of their fishing exploits, but in The Old Man and the Sea, (1952) and Islands in the Stream (published posthumously in 1970), Ernest Hemingway took up where Grey had left off, elevating his fishermen to heroes, and his great game fishes to icons. Although swordfish were certainly considered edible, the other big game fishes, such as tuna and marlins, were thought of as objects of the hunt, to be fought and conquered by brave fishermen with expensive gear and more expensive boats, plying the world’s offshore waters in pursuit of records. The record bluefin tuna, caught off Nova Scotia in 1979, weighed 1,496 pounds.

At one time, it was believed that there were two separate populations of North Atlantic bluefins, one that bred in the Gulf of Mexico and stayed in the western part of the ocean, and another that spawned in the Mediterranean and hung out in the European quadrant. But tagging experiments, pioneered by Frank Mather and Frank Carey, and followed by Barbara Block, showed that, as with so many aspects of bluefin biology, the fish confounds the conventional wisdom. Yes, the Gulf of Mexico and the Mediterranean are the breeding grounds of bluefins, but individual fishes can (and do) migrate across the entire Atlantic Ocean, and that the “two populations” are actually one meta-population distributed across the entire North Atlantic. The International Convention for the Conservation of Atlantic Tunas (ICCAT) consistently based its catch quotas on the two-population concept, and has therefore failed utterly to set realistic limits on who could fish and where, resulting in a massive collapse of the entire Atlantic bluefin population.

If possible, things are worse in the Mediterranean. Employing ideas and technology originally developed in South Australia (with the southern bluefin, Thunnus maccoyi), fishermen corralled schools of half-grown tuna, and towed them in floating pens to marine corrals where they were fed and fattened until they could be killed and shipped to Japan. There are catch limits on tuna fishing in the Mediterranean, but none on catching immature tuna and fattening them in floating pens. Every country (except Israel) on or in the Mediterranean takes advantage of this loophole and maintains tuna ranches offshore. The fishermen of Spain, France, Italy, Greece, Turkey, Croatia, Egypt, Libya, Tunisia, Algeria, Morocco, and Malta are capturing half-grown tuna by the hundreds of thousands. If you had to design a way to guarantee the decimation of a breeding population, this would be it: catch the fish before they are old enough to breed, and keep them penned up until they are killed. In 2006, the World Wildlife Fund called for the cessation of all tuna fishing in the Mediterranean, but in the light of all that money to be made, you can imagine how effective the WWF plea was.