Scientists Study Hundreds of Dead Dolphins

Date: 1/6/2006

Scientists in Tanzania are trying to discover why hundreds of dolphins were washed up dead on the coast of Zanzibar. Marine biologists also examined the dolphins as to whether US Navy sonar threw the animals off course. Villagers and fishermen buried the remains of roughly 400 bottlenose dolphins which normally live in deep waters. Experts examined the dolphins’ heads to assess whether they had been affected by military sonar. Some scientists surmise that loud bursts of sonar may disorient or scare marine mammals, causing them to surface too quickly and suffer the equivalent of what divers call the bends. A preliminary examination of the dolphins’ stomach contents failed to show the presence of squid beaks or other remains of animals hunted by dolphins. This was an indication that the dolphins had not eaten for a long time or had vomited. Their general condition showed that they had eaten recently, since their ribs were not clearly visible under the skin. Poisoning has been ruled out but experts will further examine the dolphins’ stomachs for traces of poisonous substances such as toxic ‘red tides’ of algae. Military sonar and injury to marine mammals was observed from the stranding of whales in 2000 in the Bahamas and the US Navy later acknowledged that sonar likely contributed to the stranding of the extremely shy species.

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