Steller Sea Blog

Orcas Missing From Puget Sound Thought Dead

The southern resident population of Orca whales once numbered 200-300 individuals. In the 1960’s and early 70’s, however, there was unprecedented species predation by private aquarium owners in Seattle and San Diego, who made a business out of capturing Orca for sale to private Aquaria in New York, Texas, Canada, England, and to the US Navy in Hawaii (see “Orca Capitivity” for the shocking details).

The population was reduced to just 67 individuals before Ralph Munro, Gov. Dan Evans, and Slade Gorton, then attorney general, were successful in lobbing for legislation to protect the species. Puget Sound became a sanctuary for orca whales when their capture was banned in 1976. For a while it looked like the population was slowly but steadily recovering. By 1995, the southern resident population had grown to include 98 individuals, a nearly 30 percent increase in just two decades. This is dramatic evidence that governments can enact legislation to protect species and help retain species biodiversity.

However, an end to the hunt is not an end to the threat. If only it were that simple. During the late 90s, the population declined precipitously and it has still not fully recovered from this recent drop. Because the orcas live next door to 6 million people and a global shipping infrastructure, they are exposed to a variety of disturbances, including severe toxic contamination. One dead orca found in 2002 contained the highest concentration of the toxic PCBs ever recorded in a marine mammal — dozens of times higher than levels that affect growth, reproduction and immune responses in other mammals. Add to this the recent evidence of nutritional stress due to dwindling salmon stocks, their primary food source, and the picture is starting to look more bleak than it did in the the 60’s and 70’s. Both Washington State the US federal governments have officially recognized that Puget Sound’s orcas are at grave risk of extinction.

Here is an associated press article discussing the recent disappearance of another seven orca from the southern resident population.

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Phuong Lee
Associated Press

Oct. 27, 2008 — Seven Puget Sound killer whales are missing and presumed dead in what could be the biggest decline among the sound’s orcas in nearly a decade, say scientists who carefully track the endangered animals.

“This is a disaster,” Ken Balcomb, a senior scientist at the Center for Whale Research on San Juan Island, said Friday. “The population drop is worse than the stock market.”

While the official census won’t be completed until December, the total number of live “southern resident” orcas now stands at 83.

Among those missing since last year’s count are the nearly century-old leader of one of the three southern resident pods, and two young females who recently bore calves. The loss of the seven whales, Balcomb said, would be the biggest decline among the Puget Sound orcas since 1999, when the center also tracked a decline of seven whales.

Low numbers of chinook salmon, a prime food for these whales, may be a factor in the unusual number of deaths this year, Balcomb said.

“It was a bad salmon year and that’s not good for the whales,” he said. “Everybody considers these wonderful creatures, but we really have to pay attention to the food supply.”

The three pods, or families, that frequent western Washington’s inland marine waters — the J, K, and L pods — are genetically and behaviorally distinct from other killer whales. The sounds they make are considered a unique dialect, they mate only among themselves, eat salmon rather than marine mammals and show a unique attachment to the region.

The population reached 140 or more in the last century, but their numbers have fluctuated in recent decades. They were listed as endangered in 2005.

“We may be in the beginning of another decline in the population,” said Howard Garrett, director of the Orca Network, a nonprofit education and advocacy group.

He said the whales seem to be having a harder time finding chinook salmon.

The whales recently have been traveling over greater distances than usual, suggesting they may be ranging farther for food, said Brad Hanson, a wildlife biologist with the National Marine Fisheries Service.

Lack of food may be a concern, but it’s too early to know the reason for the unusual number of presumed deaths, he said.

Pollution and a decline in prey are believed to be the whales’ biggest threats, although stress from whale-watching tour boats and underwater sonar tests by the Navy also have been concerns. In the late 1960s and early ’70s, the population fell as dozens were captured for marine parks.

The whales were making an apparentg comeback in recent years, reaching 90 in number in 2005, “but it’s been a downhill trend now for three years,” Balcomb said.

Among those missing are two female whales of reproductive age, both of which recently produced calves. One of those calves, L-111, is missing, while the other, J-39, is not.

It’s not unusual to lose older or younger whales, but losing two females in reproductive prime is “a bit of a concern” since they typically have a high survival rate, Hanson said.

One female whale, known to scientists as L-67, had the potential for two or three more calves, Hanson said.

She was the mother of “Luna,” a juvenile killer whale from Washington waters that made headlines in 2001 when he became separated from his pod and turned up in Nootka Sound, off the west coast of Canada’s Vancouver Island. A killer whale believed to be Luna died in Nootka Sound in 2006 when it was hit by the propeller of a large tugboat.

L-67 showed clear signs of emaciation — a depression behind her blow hole — before she disappeared in September, Hanson said.

“It definitely shows that she was not eating,” he said, but it’s unclear why. Researchers are performing tests on samples they collected from her weeks before she disappeared.

Others missing, according to the center, include K-7, the 98-year-old matriarch of K-pod, and L-101, a 6-year-old male who is a brother of “Luna.”

The count also includes a calf, J-43, that was born in November but is believed to have not survived the winter.

The whale census may increase if baby orcas are born this fall. And there’s a slim chance the whales may reappear elsewhere, as “Luna” did, Hanson said.

But Balcomb said: “We’ve been monitoring. They’re just gone.”

Thursday, October 30th, 2008, by Kris and is filed under "News ". You can leave a response here, or send a Trackback from your own site.