El Nino’s Warmth Plunges Marine Animals Into Peril

After being rescued half-starved from the sea and fattened up by humans, the young elephant seal called Rossi was in no rush to plunge back into the surf when her cage was opened on a sandy cove here one recent day. She looked sadly over a shoulder before waddling slowly to the shoreline.

If Rossi had reservations about returning to her watery home, it is no wonder. The fish she eats are scarce out there, so sparse that record numbers of dead or emaciated sea lions and seals have been washing ashore along the California coastline this spring. Sea mammal rehabilitation centers, such as the one in Laguna Beach that took in Rossi, are bulging with distressed animals.

Mother Nature is clearly in disarray, and scientists place the blame on El Nino, a periodically recurring shift in the ocean currents of the Pacific Ocean. The phenomenon appeared along the California coast in January, as the cold southerly current near the shoreline reversed, bringing in warm waters from the tropics that have heated the top layer of the sea 4 to 6 degrees above normal.

Deprived of the cool, wind-whipped current that usually creates an upwelling of nutrients to the sunlit ocean surface, the microscopic plankton that form the first link of the coastal food chain have failed to thrive. In turn, fish that feed on the plankton suffer. Other fish that prefer cool water, including anchovies, which are the favorite fare of sea lions and brown pelicans, have become scarce. Biologists believe that some fish may have moved farther north--to deeper water--or farther out to sea.

“The food chain has collapsed or isn’t developing this year,” said Robert Lea, a marine biologist for the California Department of Fish and Game.

The results are all too vivid. In Monterey, young sea lions crowding the harbor in search of food began venturing into a public parking lot and restrooms near a boat launching area. Befuddled city officials were forced to erect a fence to keep them out.

Yearling sea lions that normally weigh 70 to 90 pounds are being pulled out weighing a skinny 30 to 40 pounds. “You can see their ribs,” said Lance Morgan, a marine biologist at Marine Mammal Center in San Francisco.

Sea mammals are not alone in their suffering. Many of the state’s sea birds this spring are not bothering to nest or are abandoning their eggs, and many species of rockfish, an important catch for commercial fishermen, did not spawn this year along the Central California coast.

The strength of the sea change, oceanographers say, at times has equaled the severe El Nino conditions from 1982 to 1984, which caused sharp--albeit temporary--declines in numerous marine animal, bird and fish populations. The unseasonably warm ocean current is expected to dissipate along the California coast by winter.

Although cool-water fish have become scarce, tropical species have appeared far north of their usual haunts. In recent months, warm-water flying fish have been spotted in Monterey Bay. Barracuda generally found in Mexican and Southern California waters this time of year have been caught near San Francisco.

There are some benefits from the El Nino. The warm water is prompting a resurgence of sardines. The Department of Fish and Game says there is very good kelp bass fishing from Santa Barbara to Mexico because these fish get hungrier when their body temperature rises.

Southern California sportfishermen gleefully anticipate the northward pilgrimage of such tropical game fish as bigeye tuna, yellow fin tuna, skipjack and durado, some of which have been caught by fisherman sailing south just 50 miles from San Diego.

But for California’s marine mammals, the El Nino is an immediate and undisputed tragedy, especially for the young.

Rehabilitation centers that rescue stranded sea lions, harbor seals and other marine mammals say they typically pull ailing pups from the water each spring, when they are hard-pressed to compete for fish with larger and more experienced adults. But this year, the numbers of stranded young have exploded. Only recently weaned from their mothers’ milk, hapless sea lion yearlings have less lung capacity for deep-sea diving and they are less skilled hunters.

Since March, weary seals and sea lions have been arriving at a record-breaking clip at the Laguna Beach Friends of the Sea Lion Marine Mammal Center.

Two volunteers last week struggled to rescue a sickly sea lion that clung to a jagged rock at Crystal Cover State Beach. They sloshed through the surf, wrestled their slippery catch into a net and dragged it onto shore.

Despite the animal’s writhing, which snarled the net, the workers got the 45-pound pup into a cage and hoisted it onto a pickup truck for a trip to the center.

“Believe me I am tired and soaked up to here,” volunteer Robyn Battershill said before climbing into the truck bed next to the sand-caked sea lion. “It’s real difficult to get them off a rock like that. A lot of times we lose them and they go back to the ocean.”

The same day rescuers also captured two beached harbor seals at Laguna Beach and Dana Point, pushing the sea mammal population at the Friends of the Sea Lion rehabilitation center to 85, which is a record for the 21-year-old facility.

Sea World’s mammal rehabilitation center in San Diego has taken in 244 beached animals that were rescued between Los Angeles and the Mexican border, compared to 239 for all of 1991. Tom Goff, curator of mammals at Sea World, said the impact of the 1983 El Nino seemed to be more severe in San Diego County, but this year probably will mark the second-busiest since the center opened in 1964.

In Northern California, the problem is far worse. In the first six months of this year, the Marine Mammal Center in Marin County has recorded more rescues than it did a decade ago, pulling 480 troubled sea lions and other marine mammals from 1,000 miles of coastline from the Oregon border to San Luis Obispo. In 1982-83, 383 animals were rescued.

As a result of the El Nino, more sea lion yearlings than usual have been departing Southern California, where they were born on the Channel Island rookeries, and heading northward in quest of fish.

Whereas normally in June there are no more than 50 sea lions on the rocks of the Monterey breakwater, now there are 1,400 of the playful animals--enough to attract busloads of tourists with cameras.

The Marine Mammal Center’s headquarters in the Golden Gate Recreation Area is caring for 210 of the animals. They are housed in pens with fiberglass pools, cooled with sprinklers, fattened with herring and treated for respiratory ailments and other health problems at a cost of $1,500 a day, funded with nationwide donations.

Experts say that sea lions are extremely vulnerable to this year’s El Nino largely because of their burgeoning population. The animals number 110,000 statewide and have been multiplying at a rate of 5% a year for the last two decades, abetted in part by the Marine Mammal Protection Act of 1972. The result has been more animals vying for fewer fish. Sea lions are also less powerful divers than harbor seals and elephant seals, which can forage in deeper water for fish.

Unable to fend for themselves, young sea lions frequently try to nab fish being pulled aboard fishing vessels, getting tangled in hooks or nets. Sometimes it is worse. The Marin Marine Mammal Center since January has treated 40 to 50 sea lions with gunshot wounds. By law, commercial fisherman can shoot sea lions if they are destroying their catch or gear.

Many sea lions are washing up dead, according to lifeguards who find their remains.

At Bolsa Chica State Beach in Orange County, lifeguards in April and May buried 80 sea mammals, mostly sea lions, that the waves carried ashore. Halfway into June, the bodies of another 27 sea lions and four harbor seals were found and buried. “I’ve been here 18 years and it is the most I have ever seen,” said Gregory W. Scott, lifeguard supervisor at the beach.

Meanwhile, some sea bird rehabilitation centers say they have been inundated with calls in recent weeks to help starving birds.

Wendy Turner, curator of birds at Sea World, said in the last six weeks, 61 pelicans have been sent to Sea World to be rehabilitated, compared to just four during the same period a year ago. “We are predicting a very heavy summer,” she said.

Pelicans are descending on marinas in Orange County in a desperate search for food and are getting mauled by fishing hooks as they dive after fishermen’s bait.

This spring is also shaping up as poor season for sea bird reproduction.

Frank Gress, a UC Davis research biologist who has been studying California brown pelican nesting on Anacapa Island since 1978, said brown pelicans have not had a very successful breeding season on the Channel Islands’ Anacapa for several years, apparently because of a shortage of anchovies.

The El Nino has made foraging for the pelicans on Anacapa even more difficult, with the result that the birds built only 1,500 nests on the island this year, compared to 5,300 last year. About 70% have been abandoned.

Gress said when he was recently banding pelican chicks on Anacapa he found that scores of the young birds had starved to death. Most of the others were emaciated.

“Only about 10% of the chicks we banded were of normal weight,” he said.

Cormorants were also not doing well, he said. One species, the Brandt’s cormorant, have mostly abandoned breeding efforts throughout the Channel Islands.

Bill Sydeman, a program director for the Point Reyes Bird Observatory on the Farallon Islands off the coast of San Francisco, tells another discouraging story: Six of the 11 sea bird species that breed on the islands have had far fewer chicks than usual this spring.

Sydeman said the harshness of the El Nino’s impact on sea bird breeding was unexpected. “Based on the information that we had, we thought it would not be that severe,” he said. “But what we are seeing is as severe a condition as we have ever witnessed. This is as bad as it gets.”

A Coastal Calamity

As the warm ocean currents of El Nino have embraced the coast, sea life has suffered. The tropical currents, which warm the ocean up to 650 feet deep, generally carry fewer nutrients than the colder waters from the north. The result has been less plankton and fewer fish for sea lions to eat.

A Normal Year

Cold ocean currents headed south in the spring usually combine with northerly winds to cause an upwelling of nutrient-rich water from the deep sea to the shallower, sun-lit water. Plankton, the foundation of the marine food chain, feed on the nutrients.

With El Nino:

1. Upwellings of nutrient-rich water do not occur due to the presence of the El Nino current.

2. Without the nutrients, plankton is much more scarce, existing at lower depths.

3. Some types of fish, such as halibut and rockfish, move to deeper waters in search of plankton.

4. Anchovies, a staple of the sea lion diet, move north out of Southern California waters or farther out to sea. Shallow-water squid die.

5. Sea lions, which usually dive 100 to 300 feet, can’t get deep enough for a good meal.

The Sea Lion Scene

California sea lions (Zalophus californianus) are known for their intelligence, playfulness and noisy barking. Also:

* Males reach 1,000 pounds, seven feet in length; females grow to 250 pounds, five feet in length.

* Pups are born in June and July, weigh 12 to 14 pounds.

* Sea lions have external ear flaps and large flippers, which they use to move about on land.

* They prefer to eat anchovies and squid but also eat octopus, herring, juvenile rockfish and mackerel. A yearling eats about 5 to 10 pounds of fish per day; adult females eat about 25 pounds, bulls up to 60 pounds.

* They are found from Vancouver Island, Canada, to the southern tip of Baja California.

Sources: Scripps Institution of Oceanography; National Marine Fishery Service; Marine Mammal Center Education Department

Researched by LESLIE BERKMAN / Los Angeles Times