Whale deaths off Alaska island remain mystery

Researchers may never learn why the carcasses of 18 endangered whales were found floating near Alaska's Kodiak Island, a scientist working on the case said Monday.

Samples taken from one of the 10 fin whales were at least a weekold, which could throw off test results, said Kate Wynne, a marinemammal specialist for the University of Alaska Sea Grant Program.

The carcasses of eight humpback whales also were found.

The carcasses of the marine mammals were discovered betweenVictoria Day weekend and early July. Most of the animals were toodecomposed for sampling.

Both species of whales feed close together, and scientistsspeculate the animals might have eaten something toxic in watersthat were significantly warmer than average at the time. One testcame back negative for one toxin that would be present in harmfulalgal blooms, and another test is still pending, Wynne said.

"That's my leading hypothesis," Wynne said of an environmentaltoxin as a cause. "The carcasses unfortunately are getting olderand less sample-able. So we never will find out what killed thosewhales, in my mind."

Other test results also are pending, however. A muscle-tissuesample is being tested for the possibility of radionuclides from the2011 Fukushima nuclear disaster. Scientists also have looked atother possibilities, including sonar and seismic exploration.

The deaths are an unusual occurrence, Wynne said. She said she'snever heard of anything similar occurring among large baleen whalesin the U.S.

The National Oceanic and Atmospheric Administration also islooking into the deaths of a slightly larger number of whales over alarger area. NOAA is requesting the deaths to be designatednationally as an unusual mortality event, which would free upfederal funding for further studying the deaths, NOAA spokeswomanJulie Speegle said.

Along with the dead whales, dead birds including murres andshearwaters were reported earlier in the investigation.

Tests showedthe shearwaters had a high parasite count and were starving, Wynnesaid. The murres were not sampled, but Wynne said those deaths couldbe part of a die-off that occurs periodically.