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Japan, UK, Madagascar Strandings Spur Sonar Speculation

Effects of Noise on Wildlife, Seismic Surveys, Sonar Add comments

Reports of unusual stranding events around the world this week are each triggering questions about possible sonar connections, despite little clear evidence thus far. In Madagascar, over fifty melon-headed whales stranded and died after becoming trapped in a bay; in the UK, 26 common dolphins (mostly juviniles) died along the shores of an estuary river a pod of fifteen strayed into, likely feasting on fish feeding at an algae bloom, with up to seventy more following in the hours that followed, perhaps responding to their distress calls; other dolphins were found dead on two other nearby shorelines within 15km, including another estuary. In Japan, three Cuvier’s beaked whales have been found dead on beaches in the past three weeks, the latest of 81 whale fatalities (9 of them Cuvier’s) since March. In all three cases, initial comments from local environmental groups included speculation that sonar may be involved, though none clearly match the known patterns of sonar-induced strandings. (dolphins have not generally been involved; usually there are more fatalities than the single- and double-strandings in Japan; the deep-diving melon-headed whale event in Madagascar is the most suspicious, since they are usually found far offshore and, being deep divers, can be more dramatically affected by noise.) Certainly, it is a crucial to determine whether sonar was in use nearby, but the recent tendency to assume that any stranding is sonar-related could be an over-reaction, leading to jumping on tenuous connections. Still, the seas in all three areas are far from silent. In Madagascar, a seismic survey underway 45km away was shut down after the stranding; it is not clear why some think the whales would have entered a narrow bay mouth in response to such distant noise (unless the survey was in a larger bay nearby, from which fleeing whales may have been chased–details are sketchy). In the UK, Naval live fire exercises had been taking place for two weeks, and ended mid-day Sunday, with the first dolphins apparently stranding on Monday morning; the fact that dolphins died in three areas justifies suspicions that they were fleeing something at sea, through the algae blooms and fish concentrations could also be the link. In Japan, questions have lingered for several years about possible connections between strandings and US Navy bases and exercises, with a 2004 research paper finding some correlation between mass strandings and Navy activity; information from Japan is also sparse, so it is unclear whether this spring’s rash of whale strandings is more than normal in that area, or what the Naval connection may be. The UK dolphins were found fresh enough to take tissue samples for testing, while the Madagascar animals were buried in a mass grave without sampling, and the Japanese whales were too decomposed to take samples from. Sources: (UK) BBC, 6/10/08 [READ ARTICLE]Daily Mail, 6/20/08 [READ ARTICLE],BBC, 6/10/08, 2nd article [READ ARTICLE]The Independent, 6/10/08 [READ ARTICLE],(UK/Madagascar) Brisbaine Times, 6/10/08 [READ ARTICLE](Madagascar) AHN, 6/10/08[READ ARTICLE], ABC, 6/10/08 [READ ARTICLE](Japan) Mainichi Daily News, 6/10/08[READ ARTICLE]

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