maandag 4 augustus 2008

Carcass of baby orca found off San Juan Island

A dead orca calf was recovered from a beach on Henry Island's Open Bay, Saturday, by the San Juan County Marine Mammal Stranding Network.

The calf's carcass was initially sighted and photographed by a part-time resident of Henry Island during low tide the morning of July 26. The Stranding Network reported it did not get the information and pictures until several days later, so when the carcass was finally recovered, it was in a state of advanced decomposition.

It is believed the calf was born prematurely. Cause of death, as well as whether it was a member of a resident or transient pod, is expected to be determined in a necropsy being conducted by Dr. Joe Gaydos, the Stranding Network’s veterinarian and regional director of the SeaDoc Society.

“A newborn killer whale calf is usually 7 to 8 feet long and 300-400 pounds,” Stranding Network Coordinator Amy Traxler said in a press release.

“This carcass was approximately 5 feet long with an estimated weight of 70-80 pounds, so it’s likely this calf was aborted.” The placenta was lying next to the calf when originally discovered, she said.

Gaydos expected to collect tissue samples during the necropsy to determine the whale's parentage.

“If we recover viable skin and blubber, which is not always possible from a decomposed carcass, we might be able to determine if the calf is a member of the Southern resident community and possibly even narrow down the pod of origin,” Traxler said.

Fresh tissue samples also would contain information on contaminant levels and possibly provide a cause for the calf’s abortion.

It’s very rare to recover a body of a stranded killer whale. A recent paper Gaydos presented to the International Whaling Commission suggests that an average of seven killer-whale carcasses are found around the world annually, making every killer whale stranding a rare opportunity to learn more about the biology and diseases of this species.

In May 2002, L-60’s carcass was found on the outer coast of Washington. In January 2002, the body of a female transient whale was recovered by Dungeness Spit. The body of J-18 washed up by Tsawwassen, B.C. in March 2000. The body of L-51 was found in September 1999 near Victoria, B.C.

All of these carcasses were fresh, permitting scientists to learn more about the diseases of killer whales and which diseases might have an impact on the overall health of the population. Fresh necropsy samples also have helped scientists understand how contaminants impact killer whales.

The San Juan County Marine Mammal Stranding Network is one of many science and education programs at The Whale Museum. If you encounter a stranded marine mammal in San Juan County, alive or dead, call (800) 562-8832 and leave a message with your name, phone number, location, and other pertinent details of the stranding.

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