Thousands of sea lions suffering as toxic algae flourish in the Pacific

July 31, 2006|By KENNETH R. WEISS | KENNETH R. WEISS,LOS ANGELES TIMES

SAN FRANCISCO --After the last patient of the day walked out the front of Raytel Medical Imaging clinic, veterinarian Frances Gulland slipped an oversized animal crate through the back door.

Inside was a California sea lion. The animal was emaciated, disoriented and suffering from seizures.

A female with silky, caramel-colored fur, wide-set eyes and long whiskers, she was named Neuschwander, after the lifeguard who had found her six weeks earlier, comatose and trembling under a pier near San Luis Obispo.

Under treatment at the Marine Mammal Center near Sausalito, Neuschwander initially showed signs of recovery. Her eyes began to clear and focus. She frolicked in the small pool in her chain-link enclosure and wolfed down mackerel at feedings. Then she relapsed.

She stopped eating and lost 40 pounds. Her sunken eyes darted around, as if tracking a phantom just outside the cage. Her head bobbed and weaved in erratic figure-eights.

So Neuschwander was loaded into a crate at the nonprofit center, the world's busiest hospital dedicated to the care of wild marine mammals, and trucked across the Golden Gate Bridge. Gulland, the center's director of veterinary science, wanted to scan Neuschwander's brain at the imaging clinic.

After sedating the sea lion, Gulland and four assistants lifted the animal onto a gurney. They inserted a breathing tube into her throat and rolled the gurney into the great thrumming magnetic resonance imaging machine.

Neuschwander was exhibiting the classic symptoms of domoic acid poisoning, a condition that sends dazed marine mammals washing ashore in California as regularly as the spring tides.

They pick up the neurotoxin by eating anchovies, sardines and other sea life that consume algae that produce the acid. Although such algae have been around for eons, they have bloomed with extraordinary intensity along the Pacific coast for the past eight years. The blooms are part of a pattern of oceanic changes that scientists attribute to warming waters, excessive fishing, and a torrent of nutrients unleashed by farming, deforestation and urban development.

The resulting chemical changes are causing an explosion of harmful algae in the world's oceans that move through the food chain and concentrate in the dietary staples of marine mammals.

For the past 25 years, the federal government has tracked a steady upswing in beach strandings and mass die-offs of whales, dolphins and other ocean mammals.

More than 14,000 seals, sea lions and dolphins have landed sick or dead along the California shoreline in the past decade.

The type of algae that poisoned Neuschwander began blooming riotously in California waters in 1998. It is known by the tongue-twisting name Pseudo-nitzschia. A fraction of the thickness of a human hair, this javelin-shaped, single-cell organism slides through seawater on a coating of mucus.

Researchers studying Pseudo-nitzschia off the mouth of the Mississippi River have unearthed evidence in the seafloor that connects the blooms to agricultural runoff from the nation's heartland.

On the West Coast, scientists wonder whether the algae blooms explain the freakish behavior of coastal wildlife observed periodically over the years.

In 1998, sailors in Monterey Bay began bumping into what they thought were floating logs. They weren't logs: They were the bodies of sea lions.

That year, more than 400 washed ashore, dead or dying, victims of neurotoxic poisoning. Every year since, California's five marine mammal rehabilitation centers have been crowded with sea lions trembling with seizures.

Many are pregnant or suffered seizures just after giving birth.

"A California sea lion has as warm and strong of a maternal instinct with a newborn as you can see in any animal," said Robert DeLong, a government ecologist. Domoic acid can destroy that maternal bond.

Sea lions suffering from neurotoxic poisoning usually show no interest in their young. Some that previously cared for their pups shun them after suffering seizures or even attack them when they try to suckle.

"I came in one day, and pieces of the pup were everywhere," said Jennifer Collins, a veterinarian who worked at the Marine Mammal Care Center in San Pedro. "We initially thought someone had broken in and macerated one of the animals. Then we pieced it together and realized that a mother had done it to her own pup."

California sea lions have a keen sense of direction. Although their habitat ranges from British Columbia to Baja California, they return to the same breeding beaches on the same islands year after year.

But by attaching satellite transmitters to the animals, researchers have found that many victims of domoic acid poisoning - even those that appeared fully recovered - lost their way. Neuschwander was one of those who could not find her bearings.

After spending a month at the Marine Mammal Center near Sausalito last summer, the sea lion seemed so vigorous that Gulland thought she was ready to fend for herself again. She was released back into the ocean.

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