ANCHORAGE, Alaska, Oct. 22 (UPI) -- Federal researchers said they're trying to figure out why beluga whales are dying in Alaska's Cook Inlet.
The belugas have been listed as endangered, with an estimated 375 of the animals left in the area.
A report by the National Marine Fisheries Service suggests 18 possible threats to the whales, including disease, whale poaching and unnatural noise in the water from off-shore drilling and pile-driving, the Anchorage Daily News reported Wednesday.
Researchers said oil and gas spills, ocean warming and partially treated sewage discharged into Cook Inlet also may be playing a roll in the beluga whale deaths.
"Certainly oil and gas development and all in-water activities that might introduce pollutants are a concern," biologist Brad Smith told the newspaper.