Scientists head for spring rendezvous with walruses

Posted: Sunday, May 26, 2002

ANCHORAGE (AP) -- Scientists are hoping to find a few carcasses during their trek this week to Round Island off Alaska's coast, where walruses spend the summer eating, belching and male bonding.

The scientists want to find carcasses so that they can try out a veterinary crossbow on dead animals before they turn to live subjects.

The veterinary crossbow could be a real lifesaver. Scientists are hoping it will be an alternative to drugging the Bristol Bay behemoths -- a tricky procedure that too often ends in death.

Chad Jay and Dave Tessler, two U.S. Geological Survey scientists in Anchorage, and Joel Garlich-Miller, a scientist with the U.S. Fish and Wildlife Service, will spend more than a week on the island where males congregate in the summer, packed in like, well, sardines.

''They are lying every which way,'' Tessler said. ''They are belching and flatulating and pooping on each other's heads.''

Tessler can't wait.

''When they are piled together and snug in close, it looks wonderful. I want to crawl in there and lie there, but one would roll over and you would be crushed.''

It won't be all fun and games. There's serious science to do to. The scientists are working on getting more accurate population numbers in an effort to determine if stocks are healthy. The study requires attaching transmitters to walruses.

The trick with the veterinary crossbow will be adjusting it so that the anchor for the transmitter is delivered to the right spot between the walruses' thick, tough hide and the blubber. The transmitter is attached to a thin line that runs outside the walrus' body.

In past years, the scientists have had to anesthetize the walruses so they can attach transmitters to their tusks. The transmitters provide dive data so counters can compensate for walruses that are underwater and missed during the aerial surveys.

But drugging walruses comes at a high price. Since 1995, Jay has darted 112 walruses. Of those, 15 percent have died. Scientists believe the drugs may be interfering with a complicated respiratory system that allows walruses to stay underwater for nearly 10 minutes at a time.

''When we are darting them with this drug, we are interfering with this system and they can't recover normally as they would,'' Jay said.

The scientists also will be using standard crossbows to collect tissue for DNA sampling to get more information on whether there are walrus subgroups. The samples will be collected with arrows equipped with small cutting heads.

The scientists are using standard crossbows for this part of the study because they are easier to use than the veterinary crossbow and cheaper.

The standard crossbow takes two types of arrows, one that is floatable for animals hauled out on the ice or in the water. The other is tethered for land use.

The hefty males, which can weigh up to 4,000 pounds, will barely feel it when struck, Jay said. The arrows will bite in and then bounce off.

''These are very small nicks,'' he said. ''We're expecting they might pick up their heads, look around and go back to sleep again.''

If the standard crossbow can be used to collect tissue samples quickly from hundreds or thousands of animals, it could lead to a large-scale population study of Pacific walrus across their entire range from the northern Chukchi Sea to the southern Bering Sea.

''There is so much information we can gain,'' Tessler said. ''It would be so exciting if it would work.''

The last count of Pacific walruses was done 12 years ago, and because of ice conditions that year is considered unreliable, Jay said. The study put the number at about 200,000. A 1985 study put the number at 220,000. Estimates have ranged from 200,000 to nearly 240,000 over the last quarter century.

No commercial hunting of Paciific walrus is allowed. In 2001, 1,240 walruses were killed for subsistence, according to Fish and Wildlife.

Since 1995, Jay has been working mostly with male walruses summering in Bristol Bay. This summer he also plans to spend three weeks attaching transmitters to females hauled out on the ice further north in the Chuckchi Sea.

For the time being, the old method of anesthetizing the walruses to attach transmitters to the tusks will have to be used until the crossbows can be further tested.

''The hopes is to see if we can deploy these transmitters without having to capture these animals,'' Jay said. ''It would be a nice alternative.''



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