Study tracks rescued seal survival in Puget Sound

Study tracks rescued seal survival in Puget Sound

Credit: STEVE RINGMAN / The Seattle Times

After their release from cages on the shore near Friday Harbor, seals that have been through wildlife rehab make their way out into open water. Bluebell is splashing in the lead followed by Vetch, outfitted with a satellite transmitter glued on his back.


by LYNDA MAPES / The Seattle Times

Posted on October 26, 2010 at 1:16 PM

SEATTLE -  Stretched out on a bedsheet, a towel over his head with just his big, soulful eyes peeking out, Vetch the harbor seal is readied for release back to the wild after a stint at Wolf Hollow, a wildlife-rehabilitation center.

Across the country, seals like Vetch -- named by the rehab-center staff, who are deploying a native-plant theme this season -- are picked up, stranded on beaches as young pups. The experts say baby-seal pups found on the beach should be left alone, because their mother is off fishing and will return. But it doesn't always go that way.

Sometimes, baby seals are attacked by dogs or the mother is scared off by people. She might have been killed or sickened. Sometimes, pups are injured or sick. That's when stranding networks and other wildlife experts recommend a seal for pickup and rehab at a facility such as Wolf Hollow, approved by the feds to nurse seals back to health, for release back to the wild.

Vetch was found alone on a beach on San Juan Island, emaciated, dehydrated and with infected puncture wounds on his flippers. Then there's Ocean Spray: picked up on a beach when a hiker found her alone. Dogwood was found under a beachfront restaurant, his mother dead nearby on a busy public beach. Monkey Flower was marooned on a beach at a marina, trying to suckle docks and boats.

They all were cared for at Wolf Hollow, hand-fed herring by the dozen to fatten them up, treated with medications to heal their wounds and infections, and lavished when needed with nearly round-the-clock care, at a cost of about $3,000 per animal.

Wolf Hollow, one of two Washington state rehabilitation centers approved by the federal fisheries service to handle stranded seals, since 1984 has taken in and rehabilitated 569 harbor seals, at a cost of at least $1.8 million. The feds spend more than $500,000 to $700,000 a year in Oregon and Washington on programs for stranded marine mammals, including the rescue and rehabilitation of harbor seals.

Yet, for all that effort and expense, no one usually tracks the survival of the animals once they are released back into the wild. Does a rescued animal die relatively quickly? Or behave like a wild seal?

"We have some interest in knowing whether or not rehabilitation ultimately results in the animal surviving," said Brent Norberg, marine-mammal coordinator for the National Marine Fisheries Service's Northwest region. "Remarkable as it sounds, given the number of animals taken in annually, we don't know that."

Enter Vetch: Along with nine more seal pups picked up and rehabilitated in the summer, he is part of a new, first-of-its-kind study in Puget Sound. Scientists have tagged the 10 rehab seals, along with 10 wild ones, and will track them over the next year or so to see how their fates compare, before all 20 seals naturally molt their coat -- and their tags.

Scientists know the seals have died if a signal is no longer received or if the signal is stationary.

Last week, the last of the rehab seals were tagged and released from Wolf Hollow. Vetch was stoic.

Sitting astride him like a teeter totter, one volunteer steadied Vetch as another stapled two tagging devices to his tail -- numbed first with an ice pack. Next they dried a patch of his fur with a blast of compressed air and attached a transmitter between his shoulder blades with epoxy, so Vetch can be tracked by both satellite and radio signal.

The $135,479 study was a priority for the National Marine Fisheries Service, which provided most of the money. Seal rehab is big business in some states, such as California, which turns out hundreds of rehabilitated seals a year, compared with a modest 30 or so seals a year in Washington.

The study could help answer big questions, including whether rehab efforts should be undertaken at all.

There is no conservation need for rescue, after all, with the harbor-seal population in Puget Sound already at carrying capacity. Thriving on a diverse diet, seals are basking and multiplying all over Puget Sound; along the outer coast; on rocks and beaches in the San Juan Islands and along the Strait of Juan de Fuca.

Long recovered from the days when Washington state put a bounty on their heads (ended in 1960), it's no conservation issue even if lots of seals die. Lots and lots: According to the Washington Department of Fish and Wildlife, which estimates seal numbers in the state, the population could plummet by 20 percent without any threat.

But don't tell that to Leaf, a young pup recently rescued -- or her human admirers. The size and softness of a loaf of just-risen French bread, Leaf watched intently as Vetch was readied for release. Leaf's day is coming soon, but for now, Leaf was inching around like a doe-eyed Slinky taking the sun in a baby pool.

"They have big eyes and big whiskers, and they are cute," said Joe Gaydos, regional director and chief scientist for the SeaDoc Society, a nonprofit science and conservation group that is leading the study. Nobody, he noted, has much appreciation for the predators Leaf might feed, if left to die on the beach.

"We don't remember that they are supposed to feed some eagle's baby, or some crabs."

All the debate was lost on Vetch, as his dog kennel was carefully set down on the beach, with two other seals'. The other two caterpillared out of their kennels when their doors were slung open. Vetch? He was so reluctant to leave that his tenders from Wolf Hollow had to upend the kennel carefully to usher him back into the wild.

Bit by bit, he nosed to the water, finally sliding into the bay. After a few hesitant tours around the bay, he poked his body, tags and all under the glassy, green surface.