Walk along Shilshole Bay in late spring and it's likely you'll hear what sounds like an animal-control truck full of captured dogs. Some nearby condo owners, preferring a quiet...
Walk along Shilshole Bay in late spring and it’s likely you’ll hear what sounds like an animal-control truck full of captured dogs. Some nearby condo owners, preferring a quiet view, have been known to curse the cacophony.
Unfortunately for them, this is no passing truck, but an anchored float just outside the Shilshole Bay Marina breakwater, where dozens of California sea lions sprawl in an indolent pile.
“This is the place to be,” says National Marine Fisheries Service (NMFS) scientist Merrill Gosho. “It’s like Studio 54.”
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Surrounded on all sides by water, and bigger than a buoy, this one-time tie-up float is perennially popular with the mammals, and researchers like Gosho come here to study the species.
On a recent April day, he and several other NMFS biologists paid a visit. From a distance the area teemed with sleek, chocolate-brown specimens, some onboard, others bunched up in the water awaiting their turn to flop.
Sea-lion monitoring began here in 1989 after the pinnipeds (a family that includes walruses and seals) started devouring steelhead at the Hiram M. Chittenden Locks, just south of this spot. Though the entire species was blamed, only a few clever sea lions were taking advantage of the fish ladder, which slows upstream migration. After firecrackers, nets, “translocation” (a free trip to Southern California) and other tactics all failed, Sea World in Florida agreed to take in the culprits. Underwater noisemakers were then installed at the Locks to discourage future visits. NMFS now marks animals so that if a steelhead feeding frenzy recurs the main offenders can be easily identified. Scientists take advantage of this monitoring to learn more about sea-lion diet and distribution, longevity, and diseases.
Most days, this float is just a lounging spot, but on study days a dozen or more times a year it also becomes a live trap.
Approaching on two sides by small barge and skiff, the researchers prepare to jump aboard. One man leaps onto the cage at one side to tilt it and the sea lions in one direction, while across from him a second releases the trap door. Intrepid field work becomes slapstick comedy as the raft, a few sandbags short of stability today, lists sharply to one side. A cascade of over a dozen barking sea lions 5,000 glistening pounds or more of blubber and determination pours over the side of the cage and into the Sound.
In all the chaos, whooping and hollering seem the best way to regain control.
“Hey, hey, hey!”
“Back off, guys!”
“Hey, beefcake! Get off of there!”
The sea lions left behind lunge for freedom. Fortunately for the researchers, 16 don’t succeed.
Capturing and studying this group takes all afternoon. The noise abates, and within 15 minutes the pinnipeds are stretched out in the sun, quiet but for the occasional, steamy gust of air from a pair of flaring nostrils.
NMFS wildlife biologist Pat Gearin says previously-caught animals don’t avoid the trap. “Some animals have been caught 10 times or more. One became sort of our mascot it would jump on the backs of the others and come straight through the door.”
Individuals are transferred with urging and prodding from the floating cage onto the barge. Here a “squeeze cage” contains them tightly enough that there is no need to sedate the animals. Within 10 minutes, notes are taken on each mammal’s fur and whisker color (the latter can be an indication of age), length, weight and axillary (armpit) girth. Unlike, for example, orcas, California sea lions do not bear distinct markings, so researchers make their own, numbering the sea lions with a brand. This is hard for a bystander to watch. But as the acrid smoke from burning hair rises, the sea lions rarely squirm, which Gearin attributes to their thick blubber. A shot of tetracycline is often administered, leaving a mark on the mammal’s tooth that may be useful later in determining age.
Up close, their size and strength are rightly intimidating, but when at ease they appear gentle, even passive, their comically small earflaps drooping just behind half-closed eyelids. Their dog-like, tapering snout has stiff whiskers and a black nose pad, and their short, shiny fur feels oily and dense. Notoriously gassy, the noxious fish smell they emit could clear a closed room in seconds.
As expected, every sea lion on board is male with few exceptions, females stay south year-round to nurse their pups. The older males have a bump on their heads called a sagittal crest, crowned by a handsome quiff.
Though cumbersome on land, sea-lion bodies are agile, even acrobatic, in water. Along with their quick intelligence, this feature makes the species popular at marine parks. They’re also fast, traveling up to 150 miles in a day. Most of the animals we see here are migrating from feeding grounds in British Columbia to breeding grounds on the coasts of Southern California and Baja, Mexico. Their numbers peak here in early May, and all but a few are gone from mid-June to August.
While here, they are busy feeding and resting. This species requires meals equivalent to 5 percent of its body weight a day; for a 500 pound animal, that’s 25 pounds of whiting, pacific hake and herring, three favorite foods, along with the forbidden Locks steelhead.
Sometimes observers will notice sea lions in repose in the water, one flipper in the air, and assume the animals are distressed or dead. The flipper extension is thought to be a form of thermoregulation or a kind of rudder maneuver. It’s important down time: Once they’ve reached breeding grounds they begin the intense work of establishing beach territory to attract females for mating, and the males fast during this time. Pups are born, one per female, in June or July. Breeding occurs a few weeks later. Females, which may live 25 to 30 years (males have somewhat shorter lives), nurse their pups for up to a year, during which time they are also likely to be pregnant.
After decades of declining numbers due to hunting, California sea lion populations began to increase in the 1940s and benefited from the Marine Mammal Protection Act of 1972, which made it a crime to harass or kill marine mammals in U.S. waters. Unlike other marine mammals, such as Steller sea lions and orcas, California sea lion numbers are considered healthy, with an estimated population of 240,000.
Despite this increase, their numbers in Puget Sound, most likely never more than a couple thousand animals, has in recent years dwindled to an estimated 300, while increases have been noted on Washington’s outer coast; near Cape Alava, more than 5,000 have been spotted on one island alone. Gearin believes that depleted food sources in Puget Sound are the cause of this shift.
If that trend isn’t soon reversed, shoreline condo-dwellers might miss their noisy neighbors.
Kathryn True of Vashon Island and Maria Dolan of Seattle are co-authors of “Nature in the City: Seattle” (The Mountaineers Books, 2003).