Tuesday, October 17, 2006

Grim news for killer whales

Normally, the end of summer is a time when whale researchers can breathe a little easy when it comes to the Puget Sound's endangered orcas. For the most part, they get their fill of what is usually plenty of fish over the course of the summer. Typically, it's been during the winter months -- when they generally feed off the contintental shelf -- that we seem to have been losing them.

But the Center for Whales Research's annual fall surveys bring some grim news -- three adult orcas are missing -- two of them breeding females:
Three young adult killer whales - members of the family groups that spend their summers chasing salmon around Washington's San Juan Islands - have not been seen in weeks and are feared dead, researchers said Tuesday.

One of the orcas leaves a 4-month-old orphan, whose care apparently has been taken over by another female.

The three salmon-eating orca families that frequent the state's inland waters are J, K and L pods. J-pod spends virtually the entire year in the waters north of Puget Sound, while the other two groups head out to the open ocean in winter.

The pods, called the southern resident population, are unique in diet, language and DNA, and were declared an endangered species last year, with a recovery goal of 120 animals. If the three missing whales have died, the three pods will total 87 orcas, with just 23 reproductive females.

The missing mother, K-28, is from K-pod, said Kelley Balcomb-Bartok, a research assistant at the Center for Whale Research in Friday Harbor, which tracks the pods and maintains photo-identification records of each animal.

A photo of K-28 taken Sept. 1 shows a dip behind her blowhole, which indicates illness or malnutrition, he said. The 12-year-old female may also have had difficulties related to the birth.

A news release from the Center for Whale Research (via Orca Network) has more details:
The most troubling information that particularly concerns staff at the Center for Whale Research is the possible loss of K28, a 12 year-old mother, who leaves behind a four month-old orphaned calf. Killer whale calves generally do not begin to eat solid foods until they are at least a year old - and are not fully weaned of mother's milk until nearly two years of age - making it questionable whether K28's calf, K39, will survive the winter.

... If L43 is dead, she leaves behind a two year-old son, L104, a 10 year-old son, L95, and a 20 year-old daughter, L72, with two year-old grand-daughter, L105.

If L71 is dead, he leaves behind his mother, L26, his 13 year-old sister L90, and an 11 year-old nephew, L92. L71's death will be the most recent in a series of losses for matriarch L26. In 2002, L26's first born daughter, L60, washed up at Long Beach, along the coast of Washington state, orphaning her grand-daughter L92. L26's second calf died at the age of three in 1983. In 1997, her grandson, L81, died at the age of

Though the Southern Resident Orca population may have temporarily reached 90 individuals in 2006 with the addition of the three new calves, the three recent missing whales will return the population to 87. We hope that at least one more calf will be born in this population before year end.

This isn't a good sign. Losing adults, especially of breeding age, damages the population's ability to sustain itself long-term. Replacing them with calves is a start, but it doesn't resolve the immediate issues.

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