KODIAK -- Alaska fisheries face a variety of threats, but one in the Panhandle that's seldom mentioned is sea otters.

Sea otters in Southeast Alaska were hunted almost to extinction by Russian fur traders in the 18th and 19th centuries, and estimates peg the population at just 2,000 in 1911. Sea otters were reintroduced to the region by the Alaska Department of Fish and Game in the 1960s.

Sea otters can grow longer than 4 feet and weigh up to 90 pounds. They are voracious feeders and eat 25 percent of their body weight each day. Sea otters are blamed in part for the collapse of the once-lucrative abalone fishery, which ended in 1995.

Now their appetites are starting to take a bite out of other commercially-important species.

"We've closed many fisheries now -- sea cucumbers, urchins, and just this last year we closed the first geoduck fishery due to presumed sea otter predation," said Zac Hoyt, a diver and research biologist at the Fish and Game office in Petersburg.

"When you're under water in a geoduck bed, it's pretty amazing how efficient otters are at getting these big clams that burrow two or three feet under the substrate," he said.

No one knows how many sea otters have set up housekeeping in Southeast or how much shellfish they're feasting on. Hoyt and Sunny Rice, the local Sea Grant marine adviser, aim to start finding out.

"The first step of our proposed project is to get an estimate of how many otters are in southern Southeast before we can move forward with anything else," Rice said, adding that concerns by fishermen and subsistence users prompted the study.

More fishermen, especially Dungeness crabbers, are telling her they are being forced out of traditional areas by sea otters, Rice said. Should they be holding on to their permits?

"The reason we're tackling this whole thing is due to a lack of scientific information," Rice said. "It would be nice to verify what we're hearing from commercial fishermen -- they'll go into a bay and see evidence of otter predation all along the shore, and at the same time, they're not catching any crab in their pots."

Hoyt added that they want to try to estimate the take of four commercially important species by sea otters -- Dungeness crab, geoduck clams, urchins and sea cucumbers.

How fishermen and otters might co-exist remains a big question. Complicating the problem: the federal government lists sea otters as a protected species that cannot be harassed in any way.