Seven Puget Sound Orca Deaths Attributed to Lack of Food

Seven Puget Sound killer whales have gone missing this year and are presumed dead, wiping out population gains over the past six years.

A shortage of chinook salmon — the orcas' primary food — may have contributed to the unusual number of deaths, said Ken Balcomb of the Center for Whale Research, who keeps track of the individual whales.

"The pattern of their foraging suggests that there hasn't been much to eat out there," Balcomb said, adding that the disappearance of two females of reproductive age is most surprising.

The annual census of the three Puget Sound pods, listed as an endangered species, is officially released in December, but most of the seven have been missing since summer, Balcomb said. L-67, a 22-year-old female named Splash, was showing signs of emaciation before she disappeared in September, he said.

The seven include L-111, a calf born in August and not yet listed in the official count.

Including K-42, a calf born in June, the total number of Puget Sound killer whales now stands at 83.

Summer is usually prime feeding time for the orcas, as chinook salmon move through the San Juan Islands. Balcomb said he became concerned about the whales' pattern of foraging soon after they returned to the islands in June.

In good years, he said, the whales group closely together, socializing and finding food when they need it. This year, the whales were spread out and seemed to be searching far and wide.

Puget Sound orcas normally move into Central and South Puget Sound in the fall, switching their diet from chinook to chum salmon. While the chum runs are now under way, the whales appear to have moved out into the ocean. Balcomb said he expects the animals to return, and he hopes they find an adequate supply of chum before winter arrives.

It could be a tough winter for the animals if they aren't able to increase their body mass, he said.

"When they come back next spring," he said, "I think we will see fewer whales."

Balcomb contends that if the Puget Sound orcas are to survive, they need more chinook salmon. He has called for a moratorium on all fishing that takes chinook — sport, tribal and commercial — from Puget Sound to the West Coast. That would include parts of Canada and Northern California, where salmon fishing was so poor it was declared a disaster this year.

"This idea doesn't sell very well," Balcomb said, "but it is what is required."

Brad Hanson, a marine mammal biologist with the National Marine Fisheries Service, said a high level of mortality can be expected in very young whales, and it is not surprising when old animals die. But when reproductive females disappear, it raises all kinds of questions, he said.

Hanson and others have been trying to figure out which particular runs of salmon the orcas are eating by going out in a boat, watching the whales take a fish and then collecting fish scales and tissue. He also collects fecal samples of the whales and occasionally takes a biopsy of their blubber.

Informed that Splash appeared to be in poor physical condition, Hanson was able to take samples about two weeks before she died. Those fecal and tissue samples will be analyzed to see if she may have been suffering from a disease, he said.

One sign of malnutrition in an orca is the appearance of a depression behind the blow hole. Because of its appearance, the condition is called "peanut head."

Hanson said he can't be sure if Splash developed "peanut head" because she couldn't find food, was weakened by disease or a combination of the two.

Losing reproductive females in a population like this makes it that much more difficult to rebuild the numbers to safe levels, he said. Whereas the number of calves surviving in recent years has been high, this year's losses include young, old and middle-aged animals.

Hanson said he will continue his studies when the whales return to Puget Sound, and he will be on the lookout for "peanut head" the remainder of this year.

Historically, Puget Sound's orcas probably numbered between 100 and 200 animals, experts say. During captures for marine parks, their numbers dropped to 71 by 1976, when Balcomb started his official census. Since then, the population has gone in cycles: up to 83 in 1980; down to 74 in 1984; up to 97 in 1996; down to 78 in 2001; up to 90 in 2004; and now down to 83.