If possible, things are worse in the Mediterranean. Employing ideas and technology originally developed in South Australia (with the southern bluefin, Thunnus maccoyii), fishers corral schools of half-grown tuna and tow them in floating pens to marine ranches where they are fed and fattened until they can be killed and shipped to Japan. There are rules banning fishing fleets from taking undersize tuna out of the Mediterranean, but none that prevent catching immature tuna and fattening them in floating pens. Every country on the Mediterranean (except Israel) takes advantage of this loophole and maintains tuna ranches offshore. The fishers from Spain, France, Italy, Greece, Turkey, Cyprus, 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. The tuna ranches, once seen as a solution to the problem, are only making it worse. In 2006 the World Wildlife Fund called for the cessation of all tuna fishing in the Mediterranean, but given the tremendous financial rewards of the status quo, you can imagine how effective this plea was. At its meeting last November, ICCAT ignored the arguments of conservationists and set the 2008 quotas at approximately the same levels as 2007. The organization adopted a plan to scale back Mediterranean tuna fishing by 20 percent by 2010, with further reductions to follow, but the head of the U.S. delegation decried this half-measure, saying that ICCAT had “failed to live up to its founding mission.”
Even if lower quotas were in place, however, the bluefin would still be imperiled. The tuna fishery is rife with illegal, unregulated fleets that ignore quotas, restrictions, boundaries, and any other rules and regulations that might threaten their catch. Furthermore, the Japanese market—which devours about 60,000 tons of bluefin every year, or more than three quarters of the global catch—is only too eager to buy the tuna, regardless of where or how it is caught. Japanese fishers have contrived to circumvent even their own country’s restrictions, bringing in thousands of tons of illegal tuna every year and then falsifying their records. It would be good for the tuna and, in the end, good for the consumer if tuna fishing was not practiced in such a remorseless manner, but such change would entail nothing less than a modification of the fundamentals of human nature. As the tuna populations continue to fall, the Japanese demand for toro is increasing; fewer tuna will mean higher prices, and higher prices will mean intensified fishing. Intensified fishing will, of course, result in fewer tuna. (All bets would be off if the Japanese somehow relaxed their demand for maguro, but that seems as likely as Americans giving up hamburgers.) It appears that the only hope for the bluefin is captive breeding.
Cattle of the Sea
In an article entitled “When Will We Tame the Oceans?” that appeared in Nature in 2005, John Marra, a biological oceanographer at Columbia University’s Lamont-Doherty Earth Observatory, observed that “fishing in the ocean is no longer sustainable. Worldwide, we have failed to manage the ocean’s fisheries—in a few decades, there may be no fisheries left to manage.” His recommendation? A large-scale domestication of the ocean—with fish farmers breeding, raising and harvesting commercially valuable species. Marra acknowledged that existing fish farms have harmed the environment, polluting coastal ecosystems and putting additional pressure on wild fish populations by spreading disease and toxic chemicals. His solution is to move these so-called mariculture operations farther offshore, to the waters of the outer continental shelves, and to deploy much larger fish pens (closed net structures containing as much as 100,000 cubic meters of water) that could be floated below the surface and towed from one destination to another. This strategy would at least disperse the pollutants generated by fish farming, mitigating the environmental damage.