Thirty-one percent of the recovered electronic tags have been returned from the Eastern Atlantic and Mediterranean Sea by commercial fishers from Italy, Morocco, Portugal and Japan. Sixty-nine percent have been recaptured in the Western Atlantic, primarily off Maine, Nova Scotia and Cape Cod, Mass., by American, Canadian and Japanese fishers.
Researchers discovered that Atlantic bluefin considered overexploited in the Western Atlantic since 1982 often are traveling throughout the entire North Atlantic and, in some cases, into the Mediterranean Sea. Tuna tagged in the Western Atlantic in most cases resided for a year or more on Western North Atlantic feeding grounds. While many fish remained in the west, some of the recaptured fish had migrated to the Eastern Atlantic or Mediterranean Sea. Individuals also migrated from the Western Atlantic to the east and back again in the same year.
Most of the fish examined showed at least one year of western residency traveling between the Carolinas and New England and back again to the original release location. The fidelity to these two locations is associated with high primary productivity and represents bluefin feeding aggregations. A third aggregation site is near the Flemish Cap a section of the Atlantic seafloor just east of the Grand Banks off Canadas Newfoundland.
Researchers also reported that the western-tagged bluefin travel to distinct spawning grounds in the Gulf of Mexico or the Eastern Mediterranean.
"The results indicate western-tagged bluefin are vulnerable to fishing mortality from all Atlantic bluefin tuna fisheries," the authors write in Science. And, they add, tagging data emphasize "the need to protect both major eastern and western spawning regions, as they directly influence the western fishery."
This is an important consideration since the 200
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Contact: Ken Peterson, Monterey Bay Aquarium
831-648-4922
Stanford University
16-Aug-2001