tailieunhanh - Báo cáo sinh học: " Examining dolphin hydrodynamics provides clues to calf-loss during tuna fishing"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Examining dolphin hydrodynamics provides clues to calf-loss during tuna fishing. | J. Biol. Journal of Biology BioMed Central Research news Examining dolphin hydrodynamics provides clues to calf-loss during tuna fishing Pete Moore Published 4 May 2004 Journal of Biology 2004 3 6 The electronic version of this article is the complete one and can be found online at http content 3 2 6 2004 BioMed Central Ltd A combination of mathematical modeling and direct observation of the swimming behavior of dolphin mother-calf pairs has shown how the calf can gain much of the energy required for swimming if it is positioned correctly relative to the mother a situation that may be disrupted during the chases that result from tuna-fishing practices. Anyone who has bought a can of dolphin-friendly tuna knows that dolphins can be unintended victims of the tuna-fishing industry. Now a mathematical model shows that dolphin calves can gain up to 90 of the energy required for swimming if they position themselves correctly relative to their mothers but that the calves are in danger of being lost if this positioning breaks down 1 . As observations of dolphins in the wild support the model see The bottom line box for a summary of the findings the new work starts to give a possible explanation why dolphin numbers remain at unnaturally low levels despite changes in the tuna-fishing industry aimed at protecting dolphin populations. A brief history of tuna and dolphins During the 1970s an estimated 350 000 dolphins were killed each year as an unintended but inevitable bycatch of the tuna fishing in the eastern tropical Pacific Ocean see the Background box . This occurred because between 1959 and 1963 the tunafishing fleet switched from pole and line fishing to a technique using vast purse seine nets. Dolphins are caught because fishermen have known for a long time that tuna gather beneath schools of dolphins and very often The bottom line A mathematical analysis of the forces between adult dolphins and their calves indicates that if a young calf is in the right .

• Báo cáo khoa học
• Báo cáo sinh học hay
• cách trình bày báo cáo
• báo cáo sinh học
• công trình nghiên cứu sinh học
• tài liệu về sinh học