https://apnews.com/ba4aa1b10431494e8950401392b9d848

ANCHORAGE, Alaska (AP) — Beluga whales in Alaska's Cook Inlet may have changed their diet over five decades from saltwater prey to fish and crustaceans influenced by freshwater, according to a study by University of Alaska Fairbanks researchers.

An analysis of isotopes in beluga bone and teeth showed belugas formerly fed on prey that had little contact with freshwater. More recent generations of belugas fed in areas where rivers pour freshwater into ocean habitats.