Thursday, June 22, 2006

Offshore Killer Whale

Offshore Killer Whale Teeth

Bone Decay

Offshore Killer Whale Ecotype

A third group of killer whales, called offshores, have been discovered as a distinct population off the coast of North America. They are found in large groups of 30 to 60 individuals. They have been seen as far south as southern California and as far north as southeast Alaska. They are smaller than resident and transient killer whales. Their dorsal fin shape and mottled saddle patches resemble resident killer whales suggesting a closer common ancestor than with transients. Offshores have been recorded emitting discrete call types and their teeth are ground down from suspected shark prey.

On August 29, 1997 a dead killer whale was reported drifting 17 miles
offshore. It took the Strawberry Isle Marine Research Society’s small research boat eleven hours to tow the carcass to Strawberry Isle, with many re-fueling visits from whale-watching boats. The 5.5m (18ft) female orca’s saddle patch and dorsal fin identified her as O120, a member of the elusive offshore group of killer whales. No clear cause of death was found, though her heavily worn teeth and thin blubber suggest that she may have been old and far removed from her home in more southern waters.

After year of bleaching the bones in the sun, Society member Dominique Dupuis (Pipot) and a crew of volunteers put in close to 700 hours scrubbing and treating the bones with a non-toxic penetrating epoxy. Pipot and Robinson Cook created the ingenious orca-sized framework that supports the skeleton. The Build-A-Whale exhibit has inspired people in classrooms and at community events all over Vancouver Island, and will continue touring after it leaves the BC Experience.

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