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No Easy Answer for Otters

Scientists trying to understand the lagging recovery of California's population are looking at stresses on breeding females as the culprit.

November 23, 2004|Marla Cone | Times Staff Writer

MONTEREY, Calif. — Born 11 or 12 years ago, the sea otter known as Pink-White is a senior citizen in Monterey Bay. She spends her days near Lovers Point, diving for crabs, napping and grooming her luxurious fur.

Her muzzle has turned gray, yet she is healthy and fertile, and about to give birth to another pup, one of perhaps as many as nine she has mothered in her lifetime. She is a living landmark, adored by tourists and locals, her movements and eating habits tracked by biologists almost since she was born.

Floating in the kelp off Cannery Row seems a sublime life for a sea otter. But the waters of Monterey Bay are treacherous, even deadly, particularly for older females such as Pink-White, named for the colors of the identification tags attached to her flipper-like hind feet.

For reasons that have eluded scientists for several decades, California's sea otters have been struggling while most otter populations elsewhere have thrived. Now, however, scientists studying Pink-White and her kind believe that they may be closing in on one of the most baffling mysteries involving endangered species in the United States.

The latest clue is in the deaths among female otters, especially those in the reproductive prime of their lives. Females more than 4 years old have a low survival rate in the heart of their range, between Santa Cruz and Big Sur, while males are doing fine, their populations growing.

Scientists say that female otters, which spend much of their energy raising pups, seem highly susceptible to stress, unable to cope with altered conditions in the ocean off California's midsection, including infectious diseases spread by cat feces, as well as chemical pollutants and insufficient food. A creature of the shoreline, otters live their lives right where the human impact on the sea is the greatest.

California sea otters are the only wild animals with their own act of Congress. Signed by President Reagan, it authorized moving some animals to create separate populations that might protect them from oil spills.

Marine biologists know more about what individual otters eat, when they sleep and where they go than they often know about their own children.

Yet progress in protecting them has been painfully slow since the days a century ago when they were hunted almost to oblivion for their prized fur.

For the last decade, dead otters have washed ashore at the rate of three or four a week. Recently they have been dying in alarming numbers. In one month last year, nearly 50 otter carcasses were found. All this comes despite extensive efforts by scientists to comprehend why.

On an overcast Monday morning in late September, four wildlife biologists from the U.S. Geological Survey motor past the Monterey Bay Aquarium and the ragtag buildings of Cannery Row in a 20-foot Boston Whaler named Pursuit.

They are on the lookout for 14 otters, 11 of them females, fitted a year earlier with devices that record how often and how deep they dive, as well as their fluctuating body temperatures. The data are used to calculate how much energy the animals expend finding food.

A receiver on the boat beeps almost immediately, indicating that Pink-White is nearby.

Jim Bodkin of the Geological Survey's Alaska Science Center in Anchorage raises his binoculars and takes a look. Locating the otters is easy; capturing them is something else. They look placid, lolling about in the kelp. But sneaking up on an otter is virtually impossible, unless it is napping.

The scientists' work has yielded details about the lives and deaths of California's sea otters. It is a labor-intensive effort, requiring hundreds of people, thousands of man-hours and millions of dollars. To recapture the tagged otters, scientists must outnumber them.

On this day, 10 researchers are in two dive crews and a transport boat, while five spotters are onshore. At the aquarium, a veterinarian and several assistants stand by with a fully equipped operating room, waiting to open up the otters' bellies and retrieve the data devices.

Biologists Dan Monson and Heather Coletti, also from the Geological Survey's Anchorage office, are in diving suits, ready to go. They buckle on weight belts and climb overboard, moving 500 feet toward Pink-White with ultra-quiet, propeller-driven scooters, attached to 3-foot-wide nets. Bodkin watches from the boat with binoculars. "Our target's moving," he says, disappointed. "Once they start swimming around, there's not much chance."

After 28 minutes in the 57-degree water, Monson and Coletti give up and return to the boat. "I just couldn't see her," Monson says. "I forgot how thick this kelp is." Half an hour later, the divers try again but return empty-handed. "All I got was a big wad of kelp," Monson says.

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