Scientists study seals as sign of Sound’s health

Draw blood. Sample bits of contaminated blubber. Swab nostrils, mouths and behinds to pick up signs of disease. Most important: Avoid nasty bites.

That’s the protocol for biologists who poke and prod dozens of frightened harbor seals each September, then quickly release the animals to an isolated rookery off McNeil Island.

The exams help gauge the survival of the South Sound’s resident harbor seals, for decades burdened by harmful concentrations of toxic chemicals.

“For all intents and purposes, they look healthy. These hidden contaminants are invisible. You can’t see them,” said Steve Jeffries, a state Department of Fish and Wildlife biologist who has studied harbor seals for 30 years.

The dangerous compounds – such as polychlorinated biphenyls, or PCBs – show up in the blubber, affect the metabolism and make the animals vulnerable to illness, scientists said.

They are the state’s biggest population of marine mammals. They don’t migrate, and they occupy a niche near the top of the marine food chain, consuming a variety of fish, many of which also are eaten by people.

For scientists trying to define the scope and the effects of toxic contamination, harbor seals “perform a canary-in-a-coal-mine service,” said Canadian marine mammal toxicologist Peter Ross, who collaborates with Jeffries. “They are the laboratory animal of the ocean around here.”

Round ‘em up

Harbor seals are reclusive. Their favorite South Sound hangout is a sandy, protected spit on Gertrude Island, which punctuates an isolated cove on the north side of McNeil Island. Although best known as a prison, McNeil also is host to a state wildlife sanctuary, off limits to the public.

Because harbor seals shy away from people and can be fierce, there’s no easy way examine them up close.

So biologists do it the cowboy way, with an annual roundup. The biologists use fast boats and strong nets. Like cowboys, they use muscle to haul the seals to shore and hold them still. And the seals, like cattle, are branded.

“By branding animals we get to follow individuals throughout their lifetime. It’s a mark they don’t lose,” said marine mammal biologist Harriet Huber. She works for the National Marine Mammal Laboratory in Seattle and has studied South Sound harbor seals since 1990.

Huber’s research focuses on about 600 permanently marked South Sound harbor seals, their sides branded with 3-inch digits, large enough for long-distance identification by a biologist with a spotting scope. Huber’s project is the country’s only long-term life-history study of the species.

The federal Marine Mammal Protection Act, which has safeguarded seals since 1972, requires federal officials to manage the critters based on population work such as Huber’s.

A few decades ago, scientists in Canada and Alaska based their analyses on animals killed, then dissected.

Dyanna Lambourn, a state wildlife biologist, prefers the live option. From June through November, Lambourn watches the seals that haul out on Gertrude and other hideaways around the South Sound. She records each sighting of a branded seal in Huber’s database, noting births, deaths and other happenings.

On a recent visit to Gertrude, she donned rubber gloves and carefully removed a fishhook from a young pup’s mouth. People who throw fish to seals may not realize that bait can be a dangerous lure, said Lambourn, admittedly partial to the critters.

Lambourn, also a veterinary technician, orchestrated the recent roundup, which took place over several days earlier this month. On the beach, in her wet suit, she took the lead on blood draws, blubber punches and mucous-membrane swabs.

The big seals struggled to get free. Some yelped or growled. While Lambourn and others marked and examined them, one person crouched on top to hold each still.

Jeffries, who coordinates a state Fish and Wildlife Department team of Lakewood-based marine mammal biologists, has used similar capture methods since 1978. He cautioned volunteers not to put too much pressure on the animals because they might stop breathing.

Ordinarily, that’s not a problem. Of about 4,000 animals captured, eight have died, Huber said.

The biologists work fast. The entire exercise, from capture to release, took minutes.

New chemicals show up

Statewide, harbor seals number about 32,000. In the South Sound, the total is between 2,000 and 3,000, Jeffries said.

They were not so numerous 35 years ago. People shot them. Because fishermen complained that seals took too many fish, the state paid a bounty to reduce their numbers. That ended in 1960.

In 1970, the statewide seal population numbered about 5,000, Jeffries said. After the 1972 Marine Mammal Protection Act, which banned killing, the population began to recover.

In the early 1970s, a couple of early researchers noticed problems. Harbor seals were giving birth prematurely. Some pups were born with birth defects. “They raised the alarm,” said biologist John Calambokidis, of Cascadia Research in Olympia.

Later, Calambokidis analyzed archived blubber samples for contaminants such as DDT and PCBs. They have been banned in the U.S., but are persistent and build up in the food chain. Harbor seals get them from eating fish.

Contaminant concentrations in South Sound seals have declined since the 1970s, but the levels remain high enough to cause harm, scientists said. Moreover, newer chemicals, such as flame retardants, have begun to show up in harbor seals.

“The big concern is that not only are there still legacy contaminants, but new ones are being created and used that are essentially unrestricted, but similar to ones that have been banned that we know cause problems,” Jeffries said.

Ross, the toxicologist, and other researchers have recently found a link between South Sound harbor seal contaminants and impaired immune system response. Thyroid hormones also appear affected, he said.

And the pollution problem isn’t limited to chemicals. Disease-causing bacteria – probably waste runoff from people and livestock – also affects the seals. The combination of chemical and biological pollution means “South Sound seals are hit with a double whammy,” Ross said.

Ross and Jeffries have compared South Sound seals with others from less-polluted areas. “The simplified conclusion is that animals that live in more industrialized, urban environments are more contaminated,” Jeffries said. “There’s a huge human shadow we cast by our presence.”