Puget Sound orcas: Pollution, noise and loss of salmon leave their future uncertain

About four years after orcas living in Puget Sound waters were declared endangered, the prospects for their recovery are still unclear.

Their fate is inextricably linked with that of the also-troubled Puget Sound chinook salmon.

Other factors have been cited as possible culprits in the decline of the southern resident orcas, as they are called, such as noise from boats. According to most experts, however, fish are foremost.

In December 2005, the three pods of orcas living between the southern end of Puget Sound and the middle of Vancouver Island were listed as endangered under the federal Endangered Species Act.

The listing came following a petition by the Center for Biological Diversity, a national environmental group. Orcas also are listed under Canada’s Species at Risk Act, said Lynne Barre, a marine mammal specialist for the National Oceanic and Atmospheric Administration in Seattle.

The orcas landed on the Endangered Species Act two years after Puget Sound chinook salmon were listed as threatened under the same federal law.

The southern orcas’ limited numbers make the population highly vulnerable to a large oil spill or disease outbreak, experts say.

So far, the drop from 88 to 85 since the 2005 listing means the numbers have gone in the wrong direction. Seven died last year, some from old age, but a female of reproductive age died from unknown causes.

From 1965 to 1975, 45 whales were captured for marine theme parks around the world, according to the Center for Whale Research. Thirteen other whales were killed during those captures.

Noise from boats at short distances has been found to affect the whales’ sonar capabilities, according to Barre. The whales communicate and find fish by sending out sounds and sensing their bounce-back, a process called echolocation. As with pollution, the noise could be a factor in the whales’ ability to feed, said Rawson of the Tulalip Tribes.

Also, two of the three pods often venture down the coast to northern and central California, where they eat salmon that still bear traces of DDT, the pesticide banned in 1972, said Brad Hanson, a wildlife biologist for NOAA…More in heraldnet.com by Bill Sheets