Federal agency declares unual mortality event after 70 creatures found washed up on coast of North

biological oceanographer

s have launched an investigation what has caed the deaths of an unually high number of gray found washed up on the west coast of North .

About 70 have been found dead so far this year on the coasts of , Oregon, Washington and Alaska, the most since 2000. About five more have been discovered on British Columbia beaches.

s believe that is a very small fraction of the total number of that have died becae most simply sink and others wash up in such remote areas they are not recorded.

The National Oceanic and Atmospheric Administration fisheries agency on Friday declared the deaths an unual mortality event, providing additional resources to respond to the deaths and triggering the investigation.

Many of the have been skinny and malnourished, and that suggests they may not have gotten enough to eat during their last feeding season in the Arctic, agency spokesman Michael Milstein told reporters.

The eastern North Pacic gray were removed from the endangered species list in 1994 after numbers recovered from the whaling era.

The population has grown signicantly in the last decade and is now estimated at 27,000, the highest since surveys began in 1967. That has raised questions about whether their population has reached the limit of what the can stain. Another theory suggests that the loss of Arctic sea ice is a culprit.

The spend their summers feeding in the Arctic before migrating 10,000 miles (16,000 km) to winter off Mexico. Though they eat all along their route, they are typically thinning by the time they return north along the west coast each spring.

They eat many things, but especially amphipods, tiny shrimp-like creatures that live in sediment on the ocean floor in the Arctic.

For many years, ers noted that fewer calves tended to be born following years when the ice in the Chchi sea, north of the Bering Strait between Alaska and Rsia, was late to melt. The had less time to feast becae they couldnt access the feeding area, and th had less blubber to stain them on their next migration.

Last year, though, the Artic was unually warm. The were not blocked from the feeding area, and yet are still struggling this year. s believe the loss of sea ice could have led to a loss of algae that feed the amphipods. Surveys show the amphipod beds moving farther north, said Sue Moore, a biological oceanographer at the University of Washington.

In an average year, about 35 wash up in the .

More than 100 washed up in 2000, prompting NOAA to declare an unual mortality event. The resulting investigation failed to identy a cae. The die-off followed strong changes in ocean conditions in the mid-1990s, suggesting that warmer water patterns affected the availability of prey.

John Calambokidis, a with the Cascadia Collective, noted that as the searched farther afield for food, they have entered areas where they are not normally seen, including San Francisco Bay and Puget Sound. Four of the 10 gray found dead near San Francisco this year were struck by ships.

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