The tank is about 25 meters in diameter and six meters deep, and because the light level was fairly low, we could see very little until Marguritte tossed in a couple of small fish. Suddenly the surface broke with an ultramarine and chrome flash as one of the tuna charged at the baitfish. The tank came alive with froth, pierced by the sicklelike dorsal and tail fins of the tuna, which were anticipating a meal even though, as our docent explained, they had been fed only an hour before. As they circled excitedly underneath us, we could see that these were breeding-size bluefins: 300 kilograms of sleek, polished torpedo, pointed at both ends, with a dotted line of yellow finlets just before the tail, and the startling parentheses that mark the species’ horizontal keels, chrome yellow in the southern bluefin and black in the northern varieties. No one can tell a live male from a live female except another tuna.
Poised on the rim of the tank, we talked about the breeding program. “We can replicate the exact conditions in Indonesian waters where they are known to spawn naturally,” Marguritte said.
“If they usually spawn in the Southern Hemisphere summer when the days are longest and the water temperature is highest, we can make this tank conform to—pick a date, say, November 20—and set the length of daylight hours, air temperature, water temperature and even currents to conform to that moment in the Indian Ocean, south of the Indonesian archipelago.” The only variable they cannot duplicate is the depth of the water, and they are praying that it is not a critical factor in the breeding of the southern bluefin. Just south of the Indonesian arc of islands—Java, Bali, Flores, Sumba, Komodo, Timor—is the Java Trench, which descends to one of the deepest points in the Indian Ocean, nearly eight kilometers down. If depth is a factor, the Clean Seas project is doomed. The broodstock at Clean Seas did not produce offspring in 2007, but they will try again this spring.
Taming the Bluefin
At the Clean Seas conference room in the Port Lincoln headquarters, I met with Marcus Stehr, Hagen’s 42-year-old son and the managing director of the company. The day before, Marcus had been onboard one of the company’s purse seiners in the Great Australian Bight, the huge open bay off the continent’s southern coast, as a net cage containing perhaps 100 tons of tuna started on its journey to the pens off Port Lincoln. Like everyone else associated with this venture, Marcus is enthusiastic and optimistic about the potential for success and believes it is imminent. When I asked him if that success would completely change the way bluefin tuna are perceived in Australia, he said, “It’s not a question of if, mate—it’s when.”
Although the Aussies appear to be in the lead, it remains to be seen if they, the Japanese, or the Europeans will win the race to breed the bluefin in captivity. In 2005, for example, a research team at the Spanish Institute of Oceanography in Puerto de Mazarrón, Spain, successfully retrieved eggs and sperm from captive Atlantic bluefin broodstock, performed in vitro fertilization and produced larvae. (The hatchlings of bony marine fishes are called larvae because they look so different from the adults.) Somehow or other, it has to happen, because the survival of the species—and the tuna industry—depends on it.
The big-game fisher sees the bluefin tuna as a sleek and powerful opponent; to the harpooner, it is an iridescent shadow below the surface, flicking its scythelike tail to propel it out of range; the purse seiner sees a churning maelstrom of silver and blue bodies to be hauled onboard his boat; the long-liner sees a dead fish, pulled onto the deck along with many other glistening marine creatures; the tuna rancher sees the bluefin as an anonymous creature to be force-fed until it is time to drive a spike into its brain; the auctioneer at the Tsukiji fish market in Tokyo sees row on row of tailless, icy, tuna-shaped blocks; Japanese consumers see it as toro, a slice of rich red meat to be eaten with wasabi and soy sauce; to the biologist, the tuna is a marvel of hydrodynamic engineering, its body packed with modifications that enable it to outeat, outgrow, outswim, outdive, and outmigrate any other fish in the sea; and to those who wish to rescue Thunnus thynnus from biological oblivion, it has to be seen as a domesticated animal, like a sheep or a cow.