Dozens of whales are mysteriously dying off the coast of Alaska

Whales are dying off the coast of Alaska in increasingly alarming numbers. What's worse is the deaths are still a mystery.

Beginning in May, multiple endangered fin whales were discovered floating lifelessly near Kodiak, Alaska.

SEE MORE: Watch this whale covered in plastic bags approach a fisherman for help

Since then, 30 whales have been found dead—including 11 fin whales, 14 humpback whales, one grey whale and four that are yet to be identified.

See images of the whales in Alaska:

The outsized number of die-offs, nearly three times the historical average for the region, has prompted the National Oceanic and Atmospheric Administration to declare an "unusual mortality event."

Such a declaration allows the agency to respond forcefully to the deaths by developing a thorough response plan and scientific investigation in conjunction with federal, state and tribal officials. The designation also frees up extra funds and allows the agency to hire experts for a select working group.

Unusual mortality events are specific to marine mammal populations and the last was declared in 2013.