South­ern sea ot­ters re­bound, but strug­gle to re­gain range

The Republican Herald - - SCIENCE - BY ELLEN KNICK­MEYER AS­SO­CI­ATED PRESS

MOSS LAND­ING, Calif. — While threat­ened south­ern sea ot­ters bob and sun in the gen­tle waves of this cen­tral Cal­i­for­nia es­tu­ary, wildlife ex­perts up and down the West Coast are strug­gling to fig­ure out how to re­store the cru­cial coastal preda­tor to an un­der­sea world that’s fall­ing apart in their ab­sence.

South­ern sea ot­ters, nearly wiped out by cen­turies of in­dus­trial-scale hunt­ing for their fur pelts, have re­bounded from as few as 50 sur­vivors in the 1930s to more than 3,000 to­day, thanks to fed­eral and state pro­tec­tion.

But there’s a prob­lem. South­ern sea ot­ters, a top car­ni­vore that nor­mally helps keep other pop­u­la­tions in check and ecosys­tems in bal­ance, “are kind of stuck,” said Teri Ni­chol­son, a se­nior re­search bi­ol­o­gist at the nearby Mon­terey Bay Aquar­ium

De­spite decades of gov­ern­ment pro­tec­tion, south­ern sea ot­ters to­day still oc­cupy only about a fourth of their historic range. Fed­eral wildlife pol­icy calls for wait­ing for the ot­ters to spread out again on their own. The ot­ters’ habi­tat hasn’t re­ally budged beyond their cur­rent cen­tral Cal­i­for­nia en­clave, how­ever, over the past 20 years.

“At this point, I think for the pop­u­la­tion to in­crease, the range needs to ex­pand,” Karl Mayer, man­ager of the aquar­ium’s sea ot­ter pro­gram, said. It doesn’t re­ally make sense, Mayer said, “to stuff more ot­ters into a lim­ited en­vi­ron­ment.”

Mayer spoke as his boat putt-putted among sea ot­ters, har­bor seals and pel­i­cans crowd­ing the salt wa­ter es­tu­ary called Elkhorn Slough.

At the for­mer whal­ing town of Moss Land­ing, the re­stored slough forms part of the south­ern sea ot­ters’ mod­ern-day range: 300 miles of coast along the mid­dle of Cal­i­for­nia.

On this morn­ing, male sea ot­ters clasp paws with one an­other for sta­bil­ity in the wa­ter as they snooze to­gether and warm their bel­lies in the spring sun. Deeper into the water­way, fe­male ot­ters float with their young perched on their chests, or with new­born ot­ters — even more buoy­ant than adults thanks to their thick fur — bob­bing along­side them like corks.

A hun­gry sea gull stalks one fe­male ot­ter gnaw­ing on a fat innkeeper worm. Her ot­ter pup watches wide-eyed.

Though small by ma­rine mam­mal stan­dards, sea ot­ters are the largest mem­bers of the weasel fam­ily and males can grow to nearly 100 pounds. Their fur, the dens­est on earth, keeps them warm.

Efforts to get the south­ern sea ot­ters back into more of their old range re­flect grow­ing global recog­ni­tion of the ben­e­fits of restor­ing top preda­tors to their historic ter­ri­tory.

Af­ter sup­port­ing wolf ex­ter­mi­na­tion in Yel­low­stone in the first half of the 20th cen­tury, for ex­am­ple, the U.S. gov­ern­ment by the sec­ond half was aid­ing wolves’ rein­tro­duc­tion to the na­tional park. The wolves’ hunt­ing have cut what were too-large herds of deer and elk. The re­sult has been a re­bound at Yel­low­stone for all kinds of life — beavers, fish, even aspen trees, some ecol­o­gists say.

Wildlife of­fi­cials have made efforts around the world to re­store preda­tors rang­ing from birds of prey to bears, some­times con­tro­ver­sially when peo­ple be­lieve the an­i­mals are a threat to them or their liveli­hoods.

Some in the fish­ing in­dus­try op­pose the sea ot­ter’s come­back. Fish­er­men in Alaska ac­cuse the grow­ing north­ern ot­ter pop­u­la­tions there of con­sum­ing the red sea urchin hu­mans eat as sushi. Wildlife ex­perts counter that the en­tire coastal ecosys­tem, in­clud­ing the valu­able shell­fish, faces col­lapse with­out ot­ters and other preda­tors to keep things in bal­ance.

Even when hu­mans sup­port the restora­tion of a preda­tor, it isn’t easy.

Some­times, “it’s the Humpty-Dumpty syn­drome,” said Bill Rip­ple, an Ore­gon State Univer­sity ecol­o­gist and pro­fes­sor who has found that only half of efforts to re­store land car­ni­vores are suc­cess­ful.

AS­SO­CI­ATED PRESS

A sea ot­ter swims at the Mon­terey Bay Aquar­ium on March 26 in Mon­terey, Calif. Cal­i­for­nia sea ot­ters, once thought wiped out by the fur trade, are boom­ing again in a fed­er­ally pro­tected en­clave of North­ern Cal­i­for­nia coast.

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