Scientists looking for answers after eighth dead gray whale found near Wrangell

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ANCHORAGE (KTUU) - The eighth dead gray whale has been reported near Wrangell in Southeast Alaska, keeping biologists busy--and worried.

Barbara Mahoney, a Marine Mammal Stranding Coordinator for the National Fisheries Services said the scale of this year's die off is bigger than past ones she’s seen.

“The unusual event related to these gray whales is the number--the actual number--of these strandings,” she said. “They’re significantly larger, maybe a hundred larger, and already we’re in June.”

Mahoney recently had to dispatch a veterinarian to Wrangell to get a necropsy done on the whale before some of the data is lost to decomposition.

“If they’ve been dead for a while it can be difficult to get some basic information on these animals such as maybe its gender,” she said.

She says that the veterinarians can be working for up to two days digging into smelly whale flesh to get the right samples. That involves opening up the stomach to get pieces of organ tissue that are sent back to larger laboratories for analysis.

The samples from the eight whales in Alaska fit into a larger dataset that is associated with an Unusual Mortality Event (UME) of gray whales across the Pacific Ocean. From the coast of Mexico up to Canada and Alaska, over 170 dead gray whales have been found.

Since the population is migratory, the die-off that began in Mexico in January worked its way up into Alaska in May.

Data from all of the deaths are submitted to a special working group comprised of experts in related fields--whale behavior, climate, marine ecosystems--and is discussed at regular meetings.

While it is still somewhat unclear, a likely suspect is emerging: a disruption in food availability. That’s because almost all of the whales have turned up undernourished.

So why has it only been affecting gray whales? Mahoney said the distinct feeding pattern on shellfish and mollusks in the bottom sediment differentiates gray whales from other baleen whales like humpbacks. A disruption in those organisms could affect food availability for gray whales.

Three species of ice seals, which also recently have seen unusual deaths, also feed on shellfish found in the ocean floor sediment.

While unavailability of food has many trademarks of climate change, Mahoney said that they have at least ruled out disease. She said none of the deceased whales have shown any signs of disease so far.

That’s good news for communities who rely on gray whales for subsistence in Russia--their subsistence limit is set at nearly 150 whales per year--since they don’t have to worry about eating contaminated meat, but it could spell trouble in the future if the die-off continues.

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