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Another orca believed to be dead
Calf's mother is among five others missing for about a month

Orca K28 Raven with its calf K39 shown on June 20. Raven went missing a month ago, leaving K39 an orphan, and now K39 is presumed dead.

Randy Shore, Vancouver Sun
Published: Tuesday, October 24, 2006

A recently orphaned killer whale calf has been added to the list of orcas missing and presumed dead.

Five adult killers whales have disappeared in recent weeks, three from the K and L pods that live off the southern coast of B.C. and northern Washington state. One of the missing orcas is the calf's mother. Two other northern resident orcas are also missing.

The calf was last sighted Oct. 1 in the company of its aunt K22 Sekiu, also a nursing mother. The calf's mother K28 Raven has been missing for about one month, said Ken Balcomb of the Center for Whale Research on San Juan Island. K39 is believed to be 41/2 to six months

old.

"We were hopeful that the calf K39 had been adopted by its aunt, but now it's missing too," said Balcomb. Orca calves survive solely on their mother's milk for at least a year, making it unlikely the K39 would last long without its mother or an adoptive female.

"This one had luck on it's side with a nursing aunt, but it doesn't appear to have worked out," said Kelley Balcomb-Bartok, a research associate at the centre.

"I was hoping for a much happier outcome for the calf," said Balcomb-Bartok.

Adult female orcas produce one calf every five years and about 40 per cent of orca calves die in the first year of life, according to Balcomb.

The loss of so many females of reproductive age is a real concern to the researchers, who now say the pods are "demographically unstable."

"The loss of K28 -- and perhaps now her calf -- is not just one or two deaths. Her loss could represent the loss of four or five, given that she could have easily produced three or four more calves over the next 15 years or so, Balcomb-Bartok said.

"Two reproductive females lost to the southern resident pods represents a significant impact to the population for perhaps decades to come."

Three calves were born to the southern resident pods this summer, temporarily raising the population to 90. But the loss of three adults and now a calf brings the number back down to 86. Only 23 females of reproductive age remain in the southern group.

The southern resident pods, classified as endangered by both the U.S. and Canada, have made progress before this disastrous period, according to Balcomb.

"We were hoping they would creep back up toward 100 or 110 whales," he said.

Orcas feed mainly on salmon and so are dependent on the health of the local food fish stocks, Balcomb said. Anecdotally, he says sport fishermen are telling him that chinook and coho are hard to come by in interior waters.

Orcas have to eat every day, so when the summer and fall spawning runs are poor or end early, the killer whales have to go foraging in deep water as far north as the Queen Charlotte Islands and as far south as California.

The energy cost of feeding a calf is high for a nursing female, Balcomb explained. "Sometimes they don't make it."

The other orcas missing from the southern resident group are a 20-year-old male, L71 Hugo and 34-year-old L43 Jellyroll. No carcasses have been found.