The San Francisco Chronicle July 12, 2005

http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2005/07/12/MNG8SDMMR01.DTL

By Glen Martin

Chronicle Environment Writer

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Oceanic plankton have largely disappeared from

the waters off Northern California, Oregon and

Washington, mystifying scientists, stressing

fisheries and causing widespread seabird

mortality.

The phenomenon could have long-term implications

if it continues: a general decline in near-shore

oceanic life, with far fewer fish, birds and

marine mammals. No one is certain how long the

condition will last. But even a short duration

could severely affect seabird populations because

of drastically reduced nesting success,

scientists say.

The plankton disappearance is caused by a

slackening of what is known as "upwelling:" the

seasonal movement of cold, nutrient-rich offshore

water into areas near shore.

This cold water sustains vast quantities of

phytoplankton and zooplankton, which are the

basis of the marine food web. During periods of

vigorous upwelling and consequent plankton

"blooms," everything from salmon to blue whales

fattens and thrives on the continental shelf of

the West Coast.

The larger fish and baleen whales eat mostly

krill: free-floating, shrimp- like crustaceans

ranging from one to two inches, the upper size

limit of the zooplankton realm.

When the water is cold, krill swarm off the

Northern California coast by the tens of

thousands of tons. Now that they are largely

absent, fisheries and wildlife are feeling the

effects.

In perhaps the most ominous development, seabird

nesting has dropped significantly on the Farallon

Islands off San Francisco, the largest Pacific

Coast seabird rookery south of Alaska.

Bill Sydeman, the director of marine ecology for

the Point Reyes Bird Observatory, a science and

conservation organization that maintains a

research station on the Farallones, said the

collapse of the nesting season is unprecedented

in the three decades the group has monitored the

islands.

Cassin's auklets -- a relatively rare seabird

that feeds almost extensively on krill -- have

been particularly hard hit, Sydeman said.

"Normally they breed in March," Sydeman said.

"They got started late this year, and by May they

had virtually disappeared. We expect zero nesting

success for them this year, or close to it. We've

never seen anything like it."

Sydeman said other seabirds are also showing the

effects of the reduced marine productivity.

"We have little or no nesting of pelagic

cormorants (at the Farallones), and Brandt's

cormorants are nesting at reduced numbers," he

said. "Double- crested cormorant nesting is down

by 50 percent (in the Bay Area)."

Upwelling cessation is typically caused by El

Niño events -- warm water intrusions from the

equatorial Pacific. But what is happening off the

coast right now is not a true El Niño, Sydeman

said.

"We really don't have a clear idea of what it

is," Sydeman said, noting that standard El Niños

can be tracked as they progress from the equator

to temperate waters, something that hasn't

occurred in the current case.

"Some are calling it an El Niño Norte; others

think it's some sort of anomalous intrusion of

warm offshore blue water onto the continental

shelf," he said.

A recent study indicated the phenomenon may be

long term, and linked to global warming.

Last week, Fisheries and Oceans Canada -- the

federal agency dealing with Canada's marine and

inland waters -- released a report saying 2004's

spring and summer ocean surface temperatures in

the Gulf of Alaska and off British Columbia were

the warmest in 50 years.

The study concluded the record high temperatures

were caused by abnormally warm weather in Alaska

and western Canada, as well as "general warming

of global lands and oceans."

Some pulses of upwelling occurred off Northern

California in June, Sydeman said, but they're

unlikely to significantly increase marine

productivity.

"Upwelling has slackened along all the West

Coast, except for a little bit of recent activity

off Northern California," Sydeman said. "At this

point, it's too little and too late. Things

aren't going to turn around. For krill predators

in this system, it's a very serious situation."

Juvenile rockfish numbers are also way down.

"We annually survey (juvenile rockfish) from San

Diego to Cape Mendocino, and this is the lowest

catch we've recorded in the 23 years we've been

doing it," said Stephen Ralston, a supervising

research biologist at the Santa Cruz office for

the National Marine Fisheries Service, the

federal agency that oversees fisheries in federal

waters.

Like krill, young rockfish are a significant food

source for seabirds, large fish and marine

mammals; they are also essential to maintaining

healthy stocks of mature rockfish, esteemed by

commercial fishermen and sport anglers.

Off the coast of Oregon, abnormally warm marine

water is continuing unabated, affecting local

birds and salmon.

"Things are pretty grim up here," said Bill

Peterson, an oceanographer with the National

Marine Fisheries Service office in Newport, Ore.

Peterson said a major die-off of double-crested

cormorants recently occurred in Oregon, and

juvenile salmon numbers have dropped

precipitously. Both events, he said, are likely

due to the warm water.

"We do salmon surveys every spring and summer,"

he said. "Normally, we catch several hundred

salmon in the spring. This year we caught eight.

And we usually get several thousand fish in the

summer. This year, it was 80."

Peterson said the water temperature off Oregon in

late June is normally 10 degrees Celsius (about

50 Fahrenheit), "and this year it's 16 degrees

(about 61 F). Our (upper layer of warm water) is

normally 15 meters thick, and this year it's 30

meters. Krill numbers are down, and the plankton

we are seeing are as unusual as can be -- warm

water species that you'd find off San Diego or

Monterey."

Peterson said it is unlikely Oregon waters will cool significantly this summer.

"It takes an enormous amount of (offshore wind)

energy to push that much warm water offshore,

which is what we would need to see for

significant upwelling," he said. "I don't see

that happening anytime soon."

Near San Francisco, salmon have switched from

krill to bait fish, and appear to be holding

their own -- at least for now.

"The fishing is terrific," said Roger Thomas, the

president of the Golden Gate Fishermen's

Association and the owner of the recreational

angling boat the Salty Lady.

"It's true there's not much krill, but there're

lots of anchovies and sardines," Thomas said,

"and the salmon are filling up on those."

Thomas acknowledged that the bait fish wouldn't

benefit many coastal and offshore birds.

"Sardines are too big for the auklets, and even

for other species like common murres," he said.

"They rely on smaller prey species."

In fact, say scientists, krill are the keystone

forage species for almost everything that swims

off Northern California.

"It's the krill that drive the food web dynamics

off this coast," said Ellie Cohen, the executive

director of the Point Reyes Bird Observatory.

"Their absence has tremendous implications for

everything out there, right up to the humpback

and blue whales. We don't know if this is a

result of global warming or some natural cycling,

but without the krill, you could be looking at a

food web collapse."