Sea lion's plight illustrates complexity of ocean science

By Sandi Doughton
Seattle Times staff reporter

	Ted Stevens
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To appreciate the promise — and pitfalls — of viewing oceans as ecosystems, consider the Steller's sea lion.

Fisheries biologists usually manage each species separately, but the endangered Alaskan sea lion shows that approach doesn't work, says yesterday's report from the U.S. Commission on Ocean Policy.

Like all other ocean dwellers, sea lions are part of an intricate web that connects predators, prey and the marine environment — and those connections must be considered in any management plan, the report says.

At least that's the theory.

The practice, though, is proving tough. And that's despite an unprecedented, $80 million effort to understand why sea lion numbers have dropped more than 80 percent in the past three decades.

"The bottom line is, there's still no smoking gun," said Lowell Fritz, a federal biologist at the Seattle-based Alaska Fisheries Science Center.

Sen. Ted Stevens, R-Alaska, chairman of the Senate Appropriations Committee, poured money into sea-lion research after environmentalists won an injunction that banned trawlers from many lucrative fishing grounds.

But no one knew for sure whether commercial fishing was really robbing the sea lions of pollock and other food fish.

Since the research blitz was launched, scientists have undertaken more than 150 separate projects, from using satellite transmitters to track young animals as they hunt to conducting diet experiments on captive sea lions.

The work has ruled out some possible explanations.
 
Sea lions don't appear to be falling prey to disease, toxic contaminants or sharks, Fritz said. It's also clear pollock are not in short supply.

The studies have suggested some new possibilities, such as higher-than-expected predation by killer whales.

But what the work hasn't done is provide the basic answers managers need to set fishing limits and take other steps to protect the animals.

The latest surveys show that Steller's sea lion numbers are dropping precipitously in the far western reaches of the Aleutian Islands, but seem to be stabilizing everywhere else in Alaska.

Fisheries have stabilized, too, by adapting to the closures, which were relaxed over the past few years, said Terry Leitzell, who ran the National Marine Fisheries Service during the Carter administration and is now a lawyer for Icicle Seafoods in Seattle.

Fritz and Leitzell both predict the research will pay off over the next several years in a more sophisticated understanding of the many factors that seem to affect sea-lion populations. Even then, the management decisions won't be easy and the picture won't be clear — because ecosystems are so complex.

"This is typical science," Fritz said. "As you study something, you find more questions."

Sandi Doughton: 206-464-2491 or sdoughton@seattletimes.com

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