Can the world act fast enough to save the disappearing tuna?
Scientists say drastic measures need to be taken to restore the bluefin.
Jonathan Mayhew, a third-generation fisherman from Martha's Vineyard, Mass., knows firsthand that a school of northern Atlantic bluefin tuna is a marvel to behold. A former spotter pilot, Mr. Mayhew used to routinely gaze down on schools of 60, 80, and sometimes 200 of these torpedo-shaped fish, each weighing many hundreds of pounds.Skip to next paragraph
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He also knows that schools of giant tuna are a rare sight these days.
"The stocks are not there," Mayhew says. "The biomass of bluefin that comes into the Gulf of Maine is either nonexistent, or it's going elsewhere."
Scientists concur. "Our giant fishery has disappeared," says Molly Lutcavage, director of the Large Pelagics Research Center at the University of New Hampshire, Durham. "The overfishing has gone on too long and it's finally taken down what was once a big fishery."
So far this year, fishermen have pulled in only 12 percent of the 1,533-ton US quota, the worst of several years of steeply declining catches. For US fishermen, the apparent collapse of a fishery once valued $19 million (it was valued at $3.3 million in 2006) is only the latest in a series of setbacks that make it tougher to make a living.
New information on just how far this migratory fish travels has scientists thinking that overfishing in the Mediterranean and eastern Atlantic may be depleting bluefin numbers closer to the US. Others think that, perhaps due to human-driven climate change, shifting conditions in the North Atlantic are further stressing already weakened stocks. Warning of collapse, many are calling for a moratorium on bluefin harvesting, both to allow stocks to rebound and to give scientists a chance to figure out what's happening.
"We had all these complicated regulations to control the fishery [that] seem to have largely failed," says Clay Porch, a research fishery biologist at the National Marine Fisheries Service (NMFS) in Miami. "Drastic measures need to be taken to put us back on track."
At stake is not just the continued existence of a remarkable fish, but a favorable resolution to a greater conundrum: Will humankind figure out how to sustainably manage nature's bounty before there's not much left to manage?
The answer, so far, seems to be no. Despite calls by US lawmakers and scientists for a moratorium on bluefin harvesting, the International Commission of the Conservation of Atlantic Tunas (ICCAT), which decides bluefin quotas, did not meaningfully lower quotas when it convened in November. (Acknowledging overfishing, the European Commission did ban bluefin fishing for the rest of 2007.) As in past cases where regulators didn't act in time, a multitude of competing interests – in this case the 42 countries that participate in ICCAT – forestalled greater, but necessary cuts, experts say.
With the fate of bluefin hanging in the balance, scientists are now calling for a more comprehensive and, presumably, effective "systems" approach, one that takes the entire ecosystem into account when setting fishing quotas.
"Nobody's really done it," says Don Perkins, president of the Gulf of Maine Research Institute (GMRI) in Portland. "And the regulatory system is not set up to consider an individual species from a multispecies perspective." But, he says, by necessity, that's where fishery management is headed.
Fisherman face an Atlantic divide
The warm-blooded bluefin, the largest of the tuna species, travels vast distances during its life. Living up to 30 years, adults fatten up in highly productive northern waters, like, historically, those in the Gulf of Maine, and then spawn in the warmer waters of the Gulf of Mexico and the Mediterranean.
Since the early 1980s, managers have treated North Atlantic bluefin as two separate populations: eastern and western. A north-south line that bisects the Atlantic divides the two stocks. Many scientists assumed a mere 4-to-5 percent exchange between eastern and western tuna. But "no fisherman that I know of ever believed for a second that the two-stock theory was viable," says Mayhew. Enabled by new tagging technology, studies conducted during the past decade substantiate Mayhew's hunch.