Satellite tags give fresh angle on tuna quota

[摘要] The migration patterns of giant Atlantic bluefin tuna have been unravelled through satellite tagging and the results suggest that policies for managing the overfished species require an urgent rethink. This economically valuable fish has two spawning grounds in the Gulf of Mexico and the Mediterranean and thesegrounds are protected by the International Commision for the Conservatin of Atlantic Tunas. It is up to this organization to set the fishing quota for bluefin tuna which is based on an imaginary line down the middle of the Atlantic, with different fishing quotas allowed to the east and west of this line. Scientists and conservationalists have long been concerned about this policy because they suspect fish cross the dividing line when feeding in the open ocean, but up until recently they had no way to prove this theory. The advent of satellite tagging gives researchers a clear picture of the movement of the fish and various other factors such as water temperature, light level and habitat threats.