The orca is a master predator. He glides like a torpedo, his 6-foot dorsal fin slicing through the surface of the sea. He hunts down a seal, rams it repeatedly with his tail and drowns it.
These wolves of the sea stand unrivaled at the top of the food web. But their rank in the ocean’s hierarchy has given them another extraordinary--and perilous--distinction:
They appear to be the most contaminated animals on Earth.
The concentrations of industrial chemicals in orcas, or killer whales, off Washington state and Vancouver Island are the highest found in any living mammal, according to marine scientists. The poisons, subtle but insidious, have built up in their bodies to dangerously high levels.
Stars of Hollywood films and marine amusement parks, these black-and-white creatures are icons of the Pacific Northwest and British Columbia. On a typical summer day, hundreds of tourists and boaters set sail in hopes of spotting them.
Lately, though, there have been more whale-watching vessels than whales plying the picturesque waters between Seattle and Victoria.
The region’s famed orca pods are shrinking. Government officials now say there is a strong chance that these descendants of Shamu, revered in native mythology as supernatural in their survival skills, could be named an endangered species.
The region’s killer whales have been dying at a higher rate in the last five years, most disappearing without a trace. Nearly half of their calves die within months of their births.
Scientists wonder if the industrial poisons accumulating in their bodies are beginning to take a toll on their survival, impairing their ability to fight disease and to reproduce successfully.
Or perhaps the Pacific Northwest’s whales, surrounded by nature lovers in yachts, kayaks and motorboats, are falling victim to the stresses of their own popularity. The decline in salmon--a diet staple for many orca pods--also may be harming them. Most likely, scientists say, the orcas are being harmed by a combination of the urban threats they face.
Because a generation of orcas spans 10 to 15 years, researchers warn that it is too early to tell whether the recent population decline is a temporary dip or a worrisome trend. In fact, this winter showed a promising development: three new calves, bringing the total population of the resident pods that frequent the San Juan Islands to 84.
But environmentalists worry that, if they wait for scientists to decipher the trends, it could be too late to save the whales.
Long-lived, elusive and intelligent, these animals have no predators. Nothing at sea is capable of killing a killer whale.
Except a human being.
Alarmingly High Contamination Levels
In the seaside town of Sidney, at the Canadian government’s Institute of Ocean Sciences, Peter Ross opened a long-forgotten file one day in 1996.
He scanned the columns of data inside, and a number caught his eye.
250 parts per million.
At first, he didn’t believe it. These were the worst concentrations of PCBs, or polychlorinated biphenyls, he had ever seen. And they came from live killer whales swimming in the scenic waters off Vancouver Island.
“My jaw dropped,” Ross said. “I said, these animals are really hot.”
Ross decided to investigate. He pulled the blubber biopsies of 30 more whales from a laboratory freezer and tested them for PCBs.
Ross, one of the world’s foremost experts in marine mammal contamination, had reason to worry about the whales. While working in Europe a few years earlier, he had proved that PCBs weaken the immune systems of harbor seals. Animals with compromised immunity are more likely to become ill and die when exposed to disease or infections. European harbor seals experienced a massive die-off in 1988.
Ross realized, though, that the killer whales off British Columbia and Washington state made Europe’s seals look pristine.
His research has shown that male killer whales contain as much as 15 times more contamination than the seals that suffered suppressed immunity.
At those concentrations, the whales “greatly exceeded many toxic thresholds for mammals,” Ross said. Disruption of the whales’ immune systems and reproduction is likely, since, he said, there is no reason to believe that PCBs’ effects on whales are different from effects on seals.
Environmental agencies have known for years that the Seattle area’s Puget Sound is tainted with PCBs. But no one had suspected that the poison was harming the killer whales because the San Juan Islands, where they mostly live, are miles away from any industrial dumps.
“The concentrations in the orcas are surprising, in part because they visit the Seattle area and other urban bays infrequently,” said Scott Redman, science coordinator of the Puget Sound Water Quality Action Team, an arm of Washington state government. “Most of their fish come from less contaminated areas.”
Indeed, the local PCB contamination is by no means extraordinary.
“Puget Sound is about average for a polluted urban area,” said Alan Mearns, a senior scientist at the National Oceanic and Atmospheric Administration, which monitors pollutants in mussels. Santa Monica Bay is just as contaminated, and San Francisco Bay’s levels are twice as high, Mearns said.
It turns out, however, that where the orcas live does not determine how contaminated they are.
“It has nothing to do with how close you are to the pollution source, but how high you are on the food chain,” Ross said.
Worldwide, the ocean floor has become the final resting point for PCBs--long-lasting chemicals that were widely used as electrical transformer oils and hydraulic fluids until banned in the United States in 1977. PCBs enter the food web from the bottom up, accumulating in the fatty tissues of animals. Animals low on the food chain may accumulate small amounts. As predators consume those animals, they end up with much higher concentrations in their tissues.
Killer whales carry such extraordinary loads of chemicals because the animals they prey on are high on the food web and because the whales consume so much--200 pounds a day.
Also, the longer an animal lives, the more contamination it stores. Some of the region’s killer whales were born before World War I.
“They are like sponges that essentially soak these chemicals up,” Ross said.
Two types of pods frequent the waters around the San Juan Islands. The “transients,” which prey mostly on seals and sea lions, are the most highly contaminated whales. The “residents” eat only fish--mostly chinook salmon. The two types are genetically distinct, rarely mingling and never switching diets.
For each level up the food web, the concentration of pollutants in animals’ tissues can rise tenfold, even twentyfold.
A herring may carry only 1 part per million of PCBs, but the seals that eat that herring may contain 20 ppm and transient killer whales that eat those seals have levels as high as 250 ppm. Fish-eating resident killer whales also are highly contaminated because salmon are high on the food web.
Male orcas carry the chemicals their entire lives, which could explain why they live only half as long as females. Through their milk, the mothers pass a lifetime dose of the compounds into their firstborn calves.
“Cetaceans are vulnerable to accumulating large quantities of these chemicals. They aren’t able to get rid of them very easily,” said Walter Jarman, a University of Utah expert in pollutant concentrations.
The killer whales apparently are getting the chemicals from salmon and seals. But where, officials wonder, are the salmon and seals picking them up?
Some of the PCBs clearly come from local waters, where industrial and port operations deposited the chemicals in the years before they were banned. But Asia also is probably contributing to the Pacific Northwest’s problem. Airborne contaminants blow from China to North America in about a week. Salmon also probably pick PCBs up from Asia when they migrate into the North Pacific.
Alaska’s killer whales also are highly contaminated, even though there are no local dumps or sources, said Craig Matkin, a scientist with the North Gulf Oceanic Society.
In the waters off Seattle and Victoria, killer whales aren’t the only top-level feeders.
Human beings are, too.
People who regularly consume salmon or sole from Puget Sound face several health problems from the PCBs, including an elevated cancer risk. That has prompted Washington state officials to begin studying whether health warnings are needed regarding eating Puget Sound salmon and other fish.
Eating two ounces per day, which is average for recreational anglers, increases cancer risk by one cancer for every 1,000 to 100,000 people exposed, according to a 1998 Puget Sound update by state officials. Government regulatory officials usually worry about cancer risks higher than one in 1 million.
Because salmon is such a precious commodity in the region, the PCBs could become an explosive issue.
“The orca is an indicator of what could be affecting human health as well,” said Caitlin Cormier of the Washington Department of Ecology. “It becomes very personal because we’re high up on the food chain, too.”
Death Rate Has Risen Among Resident Orcas
Individually, the orcas off Washington and Vancouver Island seem robust and healthy.
But experts have noticed some disturbing trends.
The death rate has climbed in the last five years among the heavily studied three resident pods that frequent the San Juan Islands. The population peaked at 99 animals in 1995, but now 84 are left--a 15% decline in five years, according to the Center for Whale Research on San Juan Island.
Transient whales are more highly contaminated but also more mobile, making precise population counts difficult. The current population estimate is around 220.
What is killing the resident whales remains unproved. “Usually the animals just disappear. We rarely recover carcasses,” said Graeme Ellis, a researcher at Canada’s Department of Fisheries and Oceans who has been studying the region’s killer whales since the 1970s.
About 42% of calves in the resident pods die during their initial months, said John Ford, director of marine mammal research at the Vancouver Aquarium. Some females give birth successfully every few years while others produce no calves at all.
The southern population, around the San Juan Islands, is much smaller than that of northern residents, which live in remote Canadian waters and are less contaminated. The southern population also produces fewer calves.
PCBs block formation of vitamin A, a hormone. Calves are hit with a large dose in their mothers’ milk just at the time they need vitamin A to develop normally. So calf survival and calving rates “are the kinds of things that might be affected” by PCB contamination, Ellis said.
Whale populations also may not have fully recovered from the effects of marine parks and aquariums, which removed 48 of the region’s young animals in the 1960s and ‘70s, leaving a 15-year gap in calving.
Based on the recent population trends, U.S. environmental groups will soon petition the National Marine Fisheries Service to declare the resident whales endangered.
Doug DeMaster, a marine mammal expert at the fisheries service, says there is a 50-50 chance that the agency will list the orcas as endangered, which would then require the service to decide on steps to protect the animals.
“There’s certainly concern. They [the pods] are small and declining,” DeMaster said. “Contaminants are high--high enough at least in lab animals to compromise immunity. There’s also a lack of salmon and there are threats from whale watching. These things are all potentially problematic for them.”
What worries researchers is the experience of other marine mammal populations that have been heavily contaminated with PCBs.
Until the orca discovery, scientists had thought that beluga whales off Quebec, which are stricken with tumors and reproductive problems, were the world’s most chemical-laden marine mammals.
The only animals known to contain more PCBs than the Pacific Northwest’s orcas are dead--Mediterranean dolphins that died en masse from a virus epidemic.
The fates of the dolphins, belugas and the European harbor seals that Peter Ross studied could be a warning for orcas. With PCBs known to weaken animals’ immune systems, could a mass die-off be a mere virus away?
Whale Watchers May Be Adding Stress
Life can be stressful for the region’s orcas, and not just because of industrial chemicals.
On a sunny Saturday afternoon, Kari Koski is navigating a boat around the San Juan Islands, the Pacific Northwest’s most popular whale watching destination.
But Koski is not here to watch the whales. She is here to watch the people who are watching the whales.
Spotting a boater headed toward a pod of killer whales, she picks up her megaphone.
“Please shut off your engines and let the whales pass you,” she says.
Within minutes, she sees another private boat maneuvering too close.
“Vessel Cygnet,” she says into the megaphone. “Make sure you stay at least 100 yards away and go slowly while traveling with the whales. Thank you.”
Koski is a coordinator for the Whale Museum, which patrols the crowded waters around the San Juan Islands to ensure commercial and private boaters don’t harass the whales.
Biologists are concerned that the traffic, which exploded in the 1990s, may be stressing the whales, contributing to the reduction in their survival rates. Boats could be obstacles to their hunting and the engine noise could disrupt their communication.
Most whale-watching companies have agreed to follow guidelines set in recent years by the Whale Museum. Boat operators say they are, for the most part, sensitive to the animals and able to police themselves. They fear that their industry is a scapegoat for the problems facing the orcas when there is no evidence they are harming the animals.
Still, the museum’s Soundwatch crew each year detects more than 600 violations by the companies of voluntary guidelines that most whale-watching outfits have agreed to. The flotilla of private sailors and kayakers who sometimes surround whales in the narrow straits commit many more.
Few other sea creatures in recent history have come into such close contact with so many people.
By all accounts, the region’s killer whales, once the epitome of wild, have become urban dwellers.
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Common name: Killer whale
Scientific name: Orcinus orca
Adult weight: 3,000 to 12,000 pounds
Adult length: 16 to 32 feet
Lifespan: About 50 years for females, 30 years for males
Speed: Up to 30 mph
Habitat: All oceans
Calving: Every 3 to 5 years, but sometimes at intervals of as long as 10 years.
Social structure: Killer whales live in pods. In the Pacific Northwest, they are divided into transients and residents that do not interact and have different lifestyles.
Diet: About 200 pounds of meat a day. Residents eat fish. Transients eat marine mammals, mostly seals.
Population off Washington/British Columbia: 84 residents and about 220 transients