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  ENN 4 May 06
Zanzibar Dolphin Deaths Puzzle Scientists
By Ali Sultan, Associated Press

PlanetSave 1 May 06
Scientists seek to determine why hundreds of dolphins washed up dead on Zanzibar's coast
Written by Ali Sultan

PlanetArk 1 May 06
Hundreds of Dead Dolphins Wash Ashore in Zanzibar
Paula Bock is a Pacific Northwest magazine staff writer

ZANZIBAR - At least 300 dead dolphins washed ashore on a beach in Zanzibar overnight, residents said on Friday, but the cause of the deaths was unknown.

An official with the Zanzibar Fisheries Department and Marine Products, Sihaba Haji, said the islands had not witnessed the death of such a large number of dolphins.

"I can confirm the deaths of dolphins but we need time to research to establish the cause of the deaths," he said.

A resident said the dead dolphins were on a stretch of beach called Kendwa and Mkokotoni, in the north of Zanzibar that is populated by several tourist hotels. Another resident said he first saw the dolphins on Thursday.

"We started noticing them last night. All are adult dolphins. We could do nothing but photograph them," said a hotel owner who preferred not to be named.

Nariman Jidawi, a researcher at Zanzibar-based Institute of Marine Science at the University of Dar es Salaam, cited several possible reasons that could have led to the dolphins dying.

"We suspect oil pollution, eating red seaweed or simply being left behind when the tide recedes," Jidawi said.

She said the dead dolphins were Indian Ocean Bottlenose. The Indian Ocean is a migratory path and home for several species, including the Indo-Pacific hump-backed dolphin.

A Reuters witness said Zanzibar residents were seen taking dolphin meat home. But Haji warned residents against eating the dolphins, since the cause of their deaths was unknown.

Visitors to the Indian Ocean Island often enjoy dolphin tours and scuba diving.

PlanetSave 1 May 06
Scientists seek to determine why hundreds of dolphins washed up dead on Zanzibar's coast
Written by Ali Sultan

ZANZIBAR, Tanzania (AP): Scientists tried to discover Saturday why hundreds of dolphins washed up dead on a beach popular with tourists on the northern coast of Zanzibar.

Among other possibilities, marine biologists were examining whether U.S. Navy sonar threw the animals off course.

Villagers and fishermen were burying the remains of the roughly 400 bottlenose dolphins, which normally live in deep offshore waters but washed up Friday along a 2 1/2-mile stretch of coast in Tanzania's Indian Ocean archipelago.

The animals may have been disturbed by some unknown factor, or poisoned, before they became stranded in shallow waters and died, said Narriman Jiddawi, a marine biologist at the Institute of Marine Science of the University of Dar es Salaam.

Experts planned to examine the dolphins' heads to assess whether they had been affected by military sonar. Some scientists surmise that loud bursts of sonar, which can be heard for miles in the water, may disorient or scare marine mammals, causing them to surface too quickly and suffer the equivalent of what divers call the bends--when sudden decompression forms nitrogen bubbles in tissue.

A U.S. Navy task force patrols the coast of East Africa as part of counterterrorism operations. A Navy official was not immediately available for comment, but the service rarely speaks about the location of submarines at sea.

A preliminary examination of their dolphins' stomach contents failed to show the presence of squid beaks or other remains of animals hunted by dolphins. That was an indication that the dolphins either had not eaten for a long time or had vomited, Jiddawi said.

Their general condition, however, appeared to show that they had eaten recently, since their ribs were not clearly visible under the skin, she said.

Although Jiddawi said Friday that poisoning had been ruled out, experts were preparing to further examine the dolphins' stomachs for traces of poisonous substances such as toxic "red tides" of algae.

Zanzibar's resorts attract many visitors who come to watch and swim with wild humpback dolphins, which generally swim closer to shore than the Indo-Pacific bottlenose. The humpbacks, bottlenose, and spinner dolphins are the most common species in Zanzibar's coastal waters.

The most conclusive link between the use of military sonar and injury to marine mammals was observed from the stranding of whales in 2000 in the Bahamas. The U.S. Navy later acknowledged that sonar likely contributed to the stranding of the extremely shy species.

"These animals must have been disoriented and ended up in shallow waters, where they died,'' Abdallah Haji, a 43-year-old fisherman, said Saturday as he helped bury the dolphins near the bloodied beach.

Residents had cut open the animals' bellies to take their livers, which they use to make waterproofing material for boats. `

"We have never seen this type of dolphin in our area,'' said Haji, who said he has fished in Zanzibar's waters for more than two decades.

ENN 4 May 06
Zanzibar Dolphin Deaths Puzzle Scientists
By Ali Sultan, Associated Press

ZANZIBAR, Tanzania: Preliminary investigations have failed to yield an explanation of why hundreds of dolphins left their deep offshore habitat, got stranded in shallow waters and later washed up dead on Zanzibar's northern coast, a scientist said.

"It is a mystery," Narriman Jiddawi, a marine biologist at the Institute of Marine Science of the University of Dar es Salaam, said after studying tissue samples and the remains of some of the 400 common bottleneck dolphins.

Dolphin carcasses washed up Friday along a 2.5-mile stretch between Kendwa and Nungwi beaches. The dolphins had no bruises to indicate they had been entangled in fishing nets, Jiddawi said.

A U.S. Navy task force patrols the coast of East Africa in counterterrorism operations. A Navy spokesman ruled out the possibility Navy sonar might have disoriented the dolphins and led to their deaths. He said there were no U.S. Navy vessels within 580 miles of the location in the 48 hours before it happened. "In the U.S. alone, a person is 10 times more likely to be struck by lightning than for sonar to cause a marine mammal stranding," Lt. William Marks said.

Scientists said they were mystified by the mass deaths. "A day earlier, fishermen reported seeing them at sea at high tide, but the next morning they appeared dead," Jiddawi said. "We don't know why they left offshore waters in such a large number and got stranded."

Preliminary examination of their stomachs indicated the dolphins had either not eaten for a long time or had vomited severely. Their general condition, however, showed that they had not starved, she said. Experts planned to further examine the dolphins' stomachs for traces of poison, including from the toxic "red tides" of algae.

Zanzibar's resorts attract many visitors who come to watch and swim with wild dolphins. The Indo-Pacific bottlenose, humpback and spinner porpoises, commonly known as dolphins, are the most common species in Zanzibar's coastal waters, with bottlenose and humpback dolphins often found in mixed-species groups.
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