Seattle Northern fur seal sent East for breeding program

A Northern fur seal at the Seattle Aquarium soon will be top stud back East. "Isaac," born nine years ago at the aquarium, will travel next week to Boston, his new home. Biologists hope the seal will fancy his East Coast counterparts and breed with females to grow the U.S. captive population.

"I'm sure that Isaac, all his instincts being intact, will start to establish himself as the dominant animal in that new territory and will start to do different things to attract the females' attention," said Traci Belting, curator of mammals and birds at Seattle Aquarium.

Only 14 Northern fur seals live in captivity in four U.S. aquariums, and most of those animals are getting older. Seattle is home to three fur seals. Aquarium biologists recently decided to combine resources and try to increase the population. Seattle will provide the male breeder, Isaac, in exchange for a younger male, Commander, who isn't old enough to mate.

Isaac will travel to New England Aquarium in Boston, where he'll meet three females from two other East Coast aquariums. Commander, the younger male, has arrived in Seattle. The eventual goal is to boost the captive population to about 35 fur seals spread around the country, Belting said.

Wild Northern fur seals are found in the North Pacific Ocean and Bering Sea and most breed on the Pribilof Islands in the Bering Sea, north of Alaska's Aleutian Islands.

Fur seals venture into the open ocean for most of the year to find food. They return to give birth and breed on their home islands each summer.

But a decline in the wild population has biologists concerned and perplexed. The number of fur seals born on the Pribilof Islands — the largest cluster — has declined by about 5 percent each year since 1998, even after the commercial fur-seal harvest ended years ago, said Tom Gelatt, leader of the Alaska ecosystems program at the National Oceanic and Atmospheric Administration's (NOAA) Alaska Fisheries Science Center in Seattle.

"It has a lot of people shaking their heads, for sure," Gelatt said.

Commercial fishing might be putting pressure on fur seals' ability to find enough food, and climate change may be disrupting where prey usually live in the ocean, Gelatt said. But there's no smoking gun as to why part of the population is declining.

Northern fur seals are declared "depleted" under the Marine Mammal Protection Act, but aren't listed under the Endangered Species Act.

NOAA scientists researching wild fur seals often look to Seattle Aquarium's captive animals to back up research done in the field. Scientists can analyze blood samples from wild fur seals to see what kinds of critters they eat. Doing a similar study on captive fur seals lets scientists validate their methods.

"Captive animals really provide a nice sort of control sample," Gelatt said. "I'm a strong advocate that if they're captive, we should use them for research as much as we can."

Scientists also use the aquarium's fur seals to test new gadgets used in field research. These instruments measure heart rate and diving depths, among other things.

Federal laws make it difficult for U.S. aquariums to take marine mammals from the wild. Aquarium managers plan to increase the captive population only through the breeding program and rehabilitation efforts in which a stranded animal can't be released back to the wild, Belting said.

Still, some experts are opposed to keeping fur seals and other marine mammals captive in aquariums.

"The captive life for these animals is not as rich as they would have in the wild," said Sharon Young, marine issues field director for the Humane Society of the United States. "The value of these animals on exhibit, I think, is largely (for) entertainment."

But aquarium managers maintain their primary role is to promote conservation and education for visitors. Hearing about fur seals and getting to see them help the public more fully understand the species and its conservation issues, Belting said.

"That emotional connection with a living animal changes people's perspective such that it changes behavior," she said.

Michelle Ma: 206-464-2303 or mma@seattletimes.com

Information published June 16, 2009, was corrected June 16, 2009. The caption of a photo stated that Commander was from the New England Aquarium in Boston. The seal is from an East Coast aquarium.