Orca population would not survive an ecological incident, researchers say
By Nicholas Read, Special To The Sun March 22, 2010
British Columbia killer whales could become extinct in the long term if an oil spill similar in scope to that from the Exxon Valdez occurred off the coast of B.C., says a conservation biologist with the Universities of Calgary and Manitoba.Paul Paquet, one of the lead scientists on a five-year, 14,000-kilometre survey of marine mammals and sea birds along the coast between 2004 and 2009, says the health of B.C. killer whales is already so fragile thanks to pollution and over-fishing that a major oil spill could devastate them.
“The consequences for the population as a whole could be catastrophic, meaning that that population could be pushed over the edge and into a long-term slide to extinction,” Paquet said in an interview. “Given the small population of killer whales and as a population biologist, I don’t think that’s an over-statement. And it is something we should be prepared for.”
Paquet made his remarks to coincide with the release today of a report called What’s at Stake: The Cost of Oil on British Columbia’s Priceless Coast, published by the Raincoast Conservation Society to mark the 21st anniversary of the Exxon Valdez disaster in Prince William Sound, Alaska.
The report, which was written by 12 scientists from Duke University, the University of California Santa Cruz, and the University of Saint Andrews in Scotland in addition to Paquet, identifies more than 120 species of sea birds and 27 different species of marine mammals along B.C.’s coast, including harbour seals, sea lions, and humpback, and grey whales.
It says if an oil pipeline is built between Alberta and Kitimat, and the coast is opened up to oil tankers, resulting spills could have a calamitous and possibly irreversible effect on several marine mammal populations including already rare fin, sei and blue whales; on salmon and herring fisheries; and on some terrestrial species such as grizzly bears and coastal wolves that depend on autumn salmon runs as a food source.
A big spill could also deal a potentially lethal blow to B.C.’s killer whales, says Paquet, because populations are already at biologically perilous lows thanks to insidious and chronic poisoning by industrial waste and to over-fishing of salmon, a key killer whale food source. It would depend on where the spill occurred, the time of year and the weather (high winds could spread the oil), but a big spill could kill off significant numbers of killer whales immediately and have dire long-term consequences for the rest.
“These animals are already in jeopardy,” said Paquet. “It’s like they’re standing on the edge of a cliff and [an oil spill] could be the push.”
He and his fellow scientists also believe if a pipeline is built between Alberta’s oilsands and Kitimat, and oil tankers begin collecting oil from a proposed Kitimat port, a spill of Exxon Valdez proportions is inevitable.
“It’s almost a certainty that we’d have a spill,” Paquet said. “It’s only a matter of time. Industry will argue that they’ll use double-hulled ships, but that won’t necessarily preclude a spill from happening.
“I think this is a very high-risk game particularly given the coastline because it is not easily navigated.”
Craig Matkin, a killer whale biologist for the North Gulf Oceanic Society in Homer, Alaska, says studies of killer whale populations following the Exxon Valdez disaster, bears Paquet’s forecasts out. He says a killer whale population directly affected by the 1989 42-million-litre spill still hasn’t recovered from it and probably never will.
“We lost 13 out of 22 animals at the time of the spill,” Matkin said. “Others died later.”
Since then, says Matkin, as older animals have died off, the population has seen no reproduction whatsoever to the point that it now consists of only seven animals.
“When you lose females, you lose the ability to reproduce. And that’s especially hard on killer whales because they can’t pump out calves like a mouse. Their gestation period is 17 months so it takes a long time to respond to disaster like this.”
Kathy Heise, a Vancouver Aquarium marine biologist who also contributed to the report, says of particular concern is the fact that tankers likely would have to travel through Caamano Sound, an area identified by some researchers as potentially important to killer whales as Johnson Strait is. It is also of great biological significance to fin and humpback whales, she said.
And while Heise wouldn’t go as far as Paquet in predicting that a big spill could affect all B.C. killer whale populations, she said a major spill in the Strait of Juan de Fuca could wipe out the southern resident population, which is the population of orcas most familiar to BC Ferries passengers travelling between Vancouver and Vancouver Island.
“If a spill occurred in the southern resident population, it could significantly affect the long-term viability of that population,” Heise said. “It could lead to the eventual die-off of the southern residents if it was a large spill and all the southern residents were together at the time.”