A little over a year after researchers feared a drop in the Northwest's endangered orca population meant disaster, the number of the creatures has bounced back with six new babies and no members lost.
Though scientific evidence is skimpy, some marine experts say the good news might be the result of enough salmon for the majestic black-and-white mammals to eat. Others say so little is known about orcas that the baby boom could be due to any number of factors — or simply a statistical fluke.
Whatever the reason, they’re overjoyed about the new arrivals.
“We’re all very happy to see so many births,” said Susan Berta of the Whidbey Island-based Orca Network.
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“We’re all hoping that they find lots of fish to keep them healthy and keep the mothers in good condition so they can feed the calves,” she said.
The Center for Whale Research says that in 2008, eight orcas in the three pods, J, K and L, that make up the southern resident population in Washington and southwest British Columbia went missing and were presumed dead, including two females of reproductive age and the 98-year-old matriarch of K Pod. With just one surviving birth that year, the total in the three pods as of December 2008 dropped to 82.
That alarmed researchers — “This is a disaster,” Ken Balcomb, a senior scientist at the San Juan Island-based center, said in October of that year.
But in 2009, no deaths were reported and five new calves were spotted, giving a December total of 87. A sixth infant was born Jan. 3 while its family, J Pod, was near Seattle on a winter visit, making it 88.
Both Balcomb and Howard Garrett, director of the Orca Network, think food might have something to do with it.
The orcas feed on salmon — particularly chinook salmon, the largest and arguably tastiest of the Pacific species. Chinooks are listed as threatened or endangered in several Northwest waterways, including Puget Sound and the Columbia River.
“Unfortunately, they’re very picky,” Garrett said, with chinooks sometimes making up 80 percent of the orcas’ diet.
It sounds simplistic, Garrett said, but “the way that we can tag the population fluctuations is directly from the chinook runs.”
Taken as a whole, the runs in the region have held steady over at least the past two years, he said.
It’s not that simple, said Brad Hanson, a wildlife biologist with the federal Northwest Fisheries Science Center in Seattle. He said that for much of the year, little is known about what salmon stocks the orcas eat and where.
The southern orcas can range widely, from the north end of Canada’s Vancouver Island to Northern California for K and L pods.
The three pods in the southern resident community — J Pod based in the San Juan Islands, K Pod in the Strait of Juan de Fuca and L Pod off the coast — are genetically and behaviorally distinct from other orcas.
Besides sticking to this region, their sounds are considered a unique dialect, they tend to mate only within their community and they usually gather each year to socialize in a “super pod” near the San Juans.