What’s be­hind those stranded sea lions

Sci­en­tists sus­pect that a big­ger than usual al­gae bloom could be play­ing a role.

Los Angeles Times - - CALIFORNIA - JOSEPH SERNA joseph. serna@ latimes. com Twit­ter: @ JosephSerna

One of the largest toxic al­gae blooms seen off Cal­i­for­nia has shut down recre­ational and com­mer­cial fish­ing along the West Coast and could be con­tribut­ing to sea lion strand­ings in the Bay Area, sci­en­tists said this week.

The al­gae, pseudo- nitzschia, is a food source for small fish such as an­chovies and sar­dines as well shell­fish but it re­leases a neu­ro­toxin, do­moic acid, that has been known to kill marine life and is harm­ful to hu­mans in high doses.

Marine life ex­perts are in­ves­ti­gat­ing whether the blooms have con­trib­uted to an above- av­er­age num­ber of sea lion strand­ings in North­ern Cal­i­for­nia. Thou­sands of mal­nour­ished pups have come ashore since the be­gin­ning of the year, and ex­perts have strug­gled to find out why.

So far, sci­en­tists have de­ter­mined that a likely cul­prit is the un­usu­ally warm wa­ters in the Pa­cific this year, which has lim­ited the sea lions’ food sup­ply since Jan­uary, ac­cord­ing to the Marine Mam­mal Cen­ter in Sausal­ito, Calif.

But the al­gae bloom could be play­ing an out­sized role in the most re­cent in­ci­dents, said Raphael Kudela, pro­fes­sor of ocean sciences and chair­man of ocean health at UC Santa Cruz.

“I wouldn’t be sur­prised if many of the strand­ings over the past month were not re­lated to toxin,” Kudela said in an email to The Times. “We test the sam­ples for the res­cue cen­ters, so we will even­tu­ally know how many an­i­mals were ex­posed to toxin.”

Sci­en­tists con­cluded that a pel­i­can in Monterey in late May died from do­moic acid poi­son­ing and a sea lion fell ill days later but sur­vived, he added.

Since the bloom be­gan in May, the Cal­i­for­nia Depart­ment of Public Health has is­sued warn­ings on recre- ational har­vest­ing of shell­fish, and Washington state has is­sued its largest clo­sure of its mul­ti­mil­lion- dol­lar Dun­geness crab fish­ery, the Na­tional Oceanic and At­mo­spheric Ad­min­is­tra­tion said.

The Ore­gon coast has also been closed to recre­ational ra­zor clam har­vest­ing af­ter high lev­els of do­moic acid were found, that state’s Depart­ment of Agri­cul­ture said.

The al­gae typ­i­cally blooms in warm wa­ter in the spring, but this year’s bloom is the big­gest since 2000, ac­cord­ing to Kudela.

Sci­en­tists from Monterey to Van­cou­ver and even as far north as Alaska have re­ported see­ing al­gae blooms and the req­ui­site high lev­els of do­moic acid in the wa­ter, Kudela said.

A “warm blob” of wa­ter that’s been stub­bornly idle off the Pa­cific Coast this year may be con­tribut­ing to the bloom’s size and stay­ing power, said Clarissa An­der­son, a re­searcher with UC Santa Cruz’s In­sti­tute of Marine Sciences.

The blob could be “lim­it­ing the nat­u­ral ex­change of wa­ters and not al­low­ing the bloom to be pushed off­shore, as of­ten hap­pens from coastal winds in other years,” An­der­son said in an email.

“This is un­prece­dented in terms of the ex­tent and mag­ni­tude of this harm­ful al­gal bloom and the warm wa­ter con­di­tions we’re see­ing off­shore,” said Vera Trainer, a man­ager with the Marine Mi­crobes and Tox­ins Pro­gram at the North­west Fish­eries Science Cen­ter in Seat­tle.

“So long as the weather con­di­tions don’t change, the bloom could per­sist,” Kudela said. “We usu­ally ex­pect to see it go away af­ter a few weeks to a month. We are go­ing on two months, which is un­usual.”

Rick Loomis Los An­ge­les Times

AN ABOVE- AV­ER­AGE NUM­BER of sea lions have been stranded in North­ern Cal­i­for­nia. Ex­perts have strug­gled to f ig­ure out why, but sus­pect it may be caused by the al­gae toxin or un­usu­ally warm wa­ters.

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