Marra also suggested taking advantage of the inclination of certain tunas to aggregate under an object that is significantly different from their surroundings. This propensity has already been exploited by fishers in the design and implementation of fish-aggregating devices, which are towed behind boats to attract schools of tuna. Instead of netting all the fish at once, though, fish farmers could create a sustainable business by feeding, maintaining and periodically harvesting some of the tuna in the school, handling the fish in much the same way that ranchers on land manage herds of cattle.
Unless tuna can be raised as if they were domesticated animals, their world populations will continue to crash. Breeding the bluefin in captivity, however, is a major challenge. One company that is attempting this feat is Clean Seas Aquaculture Growout, owned by the Stehr Group in Port Lincoln, South Australia. The Australian government has provided Clean Seas with a grant of 4.1 million Australian dollars ($3.4 million) to assist in the commercialization of southern bluefin breeding. The company has already raised captive-bred yellowtail kingfish (Seriola lalandi) and mulloway (Argyrosomus hololepidotus), which are now in significant commercial production. In October 2006 Clean Seas airlifted southern bluefin broodstock (sexually mature males and females) from their pens to a three-million-liter (790,000-gallon) tank that had been designed to replicate the optimum conditions for spawning. Hagen Stehr, founder of the company, said in a 2006 interview in The Australian, “We’ve got it all on computer, we can make [the tank] lighter or darker, we can leave the fish in a state of well-being, we’ve got the sun going up, the sun going down.... This is a world first, the Japanese won’t try it at all, the Americans have tried it and failed and the Europeans have failed too.”
During my February 2007 visit to Port Lincoln, Rob Staunton, the farm manager for the Stehr Group, drove me to Arno Bay, 120 kilometers north of Port Lincoln, on the western shore of Spencer Gulf. I was granted limited entrée into the holy grail of the tuna business, the giant enclosed tuna tank at the Arno Bay hatchery. I say “limited” because my visit, personally sanctioned by Stehr himself, came with severe restrictions, all of which are perfectly understandable. No photography is allowed in the facility itself, because the engineering, water processing, climate control and every other element in the design of this potential miracle must be carefully safeguarded to prevent corporate theft of the ideas. Along with the grant from the Australian government, the Stehr Group has invested millions in the innovative design of this facility, and it would be a disaster if someone borrowed or modified their designs and somehow beat them to the punch. It is hard to imagine anybody replicating this massive operation without all of Australia knowing about it, but of course, entrepreneurs in other countries—Japan, for instance—are also very interested in the business of captive-breeding bluefin tuna. Indeed, Japanese scientists at Kinki University have already hatched bluefin tuna from eggs and raised them to breeding age in the laboratory but not on the commercial scale being attempted by Clean Seas.
To begin our tour, Staunton and I had to change into special white rubber boots, sterilized to prevent the introduction of alien microbes into the tanks where the bluefin tuna are nurtured. Chaperoned by Thomas Marguritte, the Frenchman-turned-Australian who manages the facility, we exchanged our white boots for blue ones as we entered the sanctum sanctorum of the Arno Bay hatchery, the tuna-breeding tank. In a cavernous room illuminated by a battery of fluorescent lights, with the quiet hum of air-conditioning as the only background noise (the temperature outside was near 38 degrees C, or 100 degrees F), we climbed up to the concrete rim of the vast tank and looked down.