When whale J-18, also known as Everett, washed up on the shores of Tsawwassen last weekend, B.C.'s southern population of killer whales dropped to 82. Only a few years ago, the community numbered about 100 whales.
And while the death of a single whale may not affect the community as a whole, it is yet another blow to a population of animals under increasing pressures. Salmon stocks -- on which the whales depend for food -- are down. Boat traffic -- which can interfere with an orca's ability to locate food -- is up. And now there's evidence that man-made toxins may be wreaking havoc on killer whale health.
"When you put them all together," said John Ford, the pre-eminent authority on West Coast killer whales and head marine mammal scientist at the Vancouver Aquarium, "you have a situation where these whales may well be under a lot of pressure."
A necropsy has been done to determine what killed J-18. The initial report, Ford said, indicates the whale had a severe case of cellulitis (an infection of the skin and blubber) that featured a ruptured ulcer about the size of a football. But it's hoped that a more extensive report due later this week will reveal more information about whether the infection was bacterial or viral, as well as the amount of toxins in the whale's body.
It's already known that J-18 showed a high level of PCB contamination. A 1996 biopsy found PCB concentrations of about 63 parts per million -- a level 90 times the concentration found in people and normal orcas.
In fact, the same study that found high levels of PCBs in J-18 also noted that the southern resident population to which he belonged contains some of the most contaminated cetaceans in the world -- even more contaminated than the St. Lawrence River's threatened beluga whales.
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As killer whales go, whale J-18 was a relative youngster. In 1978, he was born to whale J-10 and joined uncles, aunts, sisters and brothers in J-pod, one of three pods that make up B.C.'s southern community of killer whales. The 19 whales of J-pod, along with 63 other whales that make up K and L pods, inhabit the waters off Southern Vancouver Island and Puget Sound. The whales forage as a group, using vocalizations to detect fish. The orcas will eat lingcod, herring and rockfish, but their preferred food is salmon -- chinook salmon above all others.
And it is that salmon that is infusing the orca's bodies with PCBs.
When PCBs first came on the scene, the chemical compounds were considered a boon. They were chemically stable, had a high boiling point, insulated well and were non-flammable. They were used in hundreds of industrial applications such as the transfer of electricity and heat; they were used in making paint, plastic and rubber products and in producing pigments, dyes and carbonless copy paper. In the United States, more than 1.5 billion pounds (6.75 million kilograms) of PCBs were manufactured before production was halted in 1977. In Canada, PCBs are no longer manufactured or imported.
Despite being banned in the 1970s, more than 200 kinds of PCBs can still be found in soil and water. The chemical stability that made them so attractive to industry also means they can take decades to break down.
PCBs have been linked to all kinds of health problems, in people and animals. In marine mammals, for example, PCBs can impair reproduction, can disrupt the endocrine (hormonal) system, cause skeletal abnormalities and weaken the immune system.
The infection that killed J-18 may be linked to such an effect, said Peter Ross, a department of fisheries and oceans researcher who is lead author of a study on high PCB concentrations in wild killer whales.
"While death is a part of the natural world, I do have my concerns that the kinds of levels of these kinds of chemicals that we're seeing in the killer whales might be contributing to extra stress or increased mortality or adversely affecting their health," Ross said.
The other thing about PCBs is that they're not water soluble. Their physical composition essentially forces them to attach to something other than water. In the ocean, the PCBs latch on to marine plants and animals.
"They will attach to fatty cells in algae and phytoplankton and outer walls of bacteria, which will get eaten by other invertebrates," Ross said.
Those invertebrates get eaten by smaller fish. The smaller fish get eaten by bigger fish. The bigger fish then get eaten by killer whales.
Being at the top of their particular food chain, killer whales reap the result of something called bioaccumulation. Here's how it works: when an animal ingests PCB-laden fat, its body burns off the fat in producing energy. But it can't break down or burn up all the PCBs because they are so persistent.
"It means," says Ross, "that the animal at the top of the food chain is invariably the animal that accumulates the most of these chemicals."
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B.C.'s southern resident killer whale population is not alone in its contamination. The northern resident orca community, made up of about 16 pods of 250 whales, plies the waters of mid Vancouver-Island, the Queen Charlotte Islands and southeast Alaska. It too is affected by high levels of PCB contamination -- although not as badly as the southern community. B.C.'s other distinct killer whale population, known as transient whales, also show high levels of PCB contamination. These whales, which inhabit offshore waters, get their PCBs through their diet of seals, sea lions and porpoises.
Does the loss of J-18 and other whales over the last few years indicate a darker time ahead for orcas in B.C.?
"It's too early to say that this decline over the last five years is a long-term trend," Ford said. "But when you're dealing with such small numbers, a few births or deaths one way or another can influence the trend.
"What concerns me is I'm not sure how the situation is going to improve for
them. The projections for the Georgia Basin are for incredible urbanization.
And the question is, are we going to be able to provide a good enough
environment for these whales to want to stay here?"
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