FRIDAY HARBOR, Wash. (AP) -- A 38-year-old female killer whale known as Tahoma, or, more technically, J-10, is missing and believed dead.
Biologists who monitor the killer whale population in Western Washington's inland waters continue to gather evidence that could help decide whether the whales deserve federal protection under the Endangered Species Act.
J-10 is the mother of J-18, a 22-year-old killer whale that died and washed up recently on a beach in British Columbia. The average lifespan for an orca, or killer whale, is roughly that of a human.
Nobody can be certain that J-10 is dead, said Dave Ellifrit of the Center for Whale Research here. But all the other whales in J pod have been spotted by observers. The black and white whales can be identified by their markings.
''If J-10 was still alive, she should have been there,'' Ellifrit said. ''We don't doubt that she is dead.''
Tissue samples from J-18 are being examined to narrow the cause of death. Killer whales from the southern resident groups -- J, K and L pods -- are known to have high levels of PCBs in their tissues. PCBs may disrupt the immune and reproductive systems of the whales, experts say. PCBs and other toxic chemicals may have contributed to the deaths, Ellifrit said, ''but there are so many factors involved.''
The latest death brings the known number of southern resident whales down to 81, although a final tally won't be made until K and L pods return from the ocean.
When K and L pods return, the first questions will be how many of the whales have survived the winter and how many calves were born. Meanwhile, killer whale biologists were recently invited by the National Marine Fisheries Service to offer their views about various risks facing the southern resident population.
''All the top scientists in Canada and the U.S. attended,'' said Rich Osborne of The Whale Museum here. A report from the meeting may form the scientific basis of a petition to seek a listing under the Endangered Species Act. The process may be completed in June, after the arrival of K and L pods, Osborne said.
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