The whales’ deaths could be causing a decline in whale populations

The whales' deaths could be causing a decline in whale populations

Gray whales continue to wash up dead and emaciated, but causes remain elusive — and scientists say we may know less than we think.

Scientists say the mystery of gray whales’ bizarre and unexplained deaths has led to a “disastrous” rush to the bottom of the ocean with the risk of species-extinction. But as an increasingly popular form of tourism, the whales are now coming to represent an important resource.

“The mortality rate is very high,” said biologist Richard Butler, director of the Center of Whale Research at the Oregon State University. He thinks that’s because the whales have gotten closer to fishing gear — or to oil and gas platforms — that can damage their brains. He also said an increasing whale population has meant too many females have spawned more offspring, which may be less able to feed their young.

The deaths have prompted a public debate because so little is known about what’s going on in the whales’ bellies. But there have been some clues from the whales themselves.

The whales appear to be dying young — at least, when it comes to the length of their teeth. “The short, thin teeth of young calves means they’re likely to die in the first year of their lives, which is very rare and most likely a symptom of their being a younger calf,” said Butler of the University of California, San Diego.

“The reason they have shorter teeth in their second year of life is probably they are becoming milk-weaned. That means the calf has not developed strong jaws for taking food. We’re starting to see evidence for some of those teeth being replaced with new teeth that were likely milk teeth.”

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Scientists believe the death of the gray whales — with more than a million whales in the Pacific Northwest alone — could start to cause a decline in their population.

“We don’t know how many whales are dying

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