ANCHORAGE, Alaska (AP) -- A new study says Alaska's endangered Steller sea lions may have trouble recovering because killer whales and other predators such as sharks are taking a toll on juvenile animals that never make it to breeding age.
The study by researchers at Oregon State University and the Alaska Sealife Center does not reach conclusions as to why Alaska's western population of Steller sea lions declined by about 80 percent.
Among the suspected causes are predators, climate change, or a shift in sea lion prey that has been less nutritious.
Oregon State marine mammal expert Markus Horning was the lead author of the new study that used transmitters to track 36 juvenile sea lions in the eastern Gulf of Alaska.
The study says predation on juveniles may have been significantly underestimated.