DURHAM, N.H. The quality of giant bluefin tuna caught in the Gulf of Maine has declined significantly since the early 1990s, researchers at the University of New Hampshire have found by analyzing detailed logbooks from a commercial tuna grader at the Yankee Fishermans Co-op. The findings, published this week in Fishery Bulletin, indicate potential changes in food sources, shifts in reproductive or migratory patterns, or the impact of fishing may be the cause of this decline.
Walter Golet, a Ph.D. candidate in UNHs Large Pelagics Research Lab, along with UNH research assistant professor Andy Cooper and Large Pelagics Lab director Molly Lutcavage, partnered with veteran tuna grader Robert Campbell at the Yankee Fishermans Co-op in Seakbrook, N.H. to analyze the quality of 3,082 Atlantic bluefin tuna (Thunnus thynnus). In a drawer, he had two or three notebooks with every fish he graded in the last 14 years, from 1991 2004, says Golet. Golets findings corroborated observations by fishermen, brokers and cooperative managers: Not only is the number of giant bluefin in the Gulf of Maine declining, the condition of those fish caught is of much lower quality.
Specifically, Golet and co-authors analyzed the fat and oil content and shape of the tuna. Fat content is in high demand for the market, because thats what makes the meat taste good, he says, noting that fish with well-marbled tail meat, fat in their mid-section muscle and belly, and a rotund shape can command upwards of $50 per pound on the sushi market.
Beyond the tekkamaki, however, fat content is a valuable indicator of the overall health condition of the bluefin. Highly migratory, traveling from their spawning grounds to the Gulf of Maine and possibly across the Atlantic, Atlantic bluefin have high metabolisms and energetic needs. Not surprisingly, bluefin caught in June, shortly after arriving in the
|Contact: Beth Potier|
University of New Hampshire