Summary: Under § 1383 of the Marine Mammal Protection Act (MMPA), 16 U.S.C. § 1361 et seq., the Animal Welfare Institute (AWI), Whale and Dolphin Conservation (WDC), Cetacean Society International, and Earth Island Institute hereby petition the Secretary of the U.S. Department of Commerce, through the U.S. National Marine Fisheries Service (NMFS), to designate Sakhalin Bay-Amur River beluga whales (Delphinapterus leucas) in the Sea of Okhotsk as a “depleted” stock. As described herein, the best scientific information available indicates that these beluga whales constitute a stock that is well below its optimum sustainable population (OSP) and, under the MMPA, qualify for such designation. The evidence also suggests that the stock continues to decline and faces a number of risk factors, providing additional impetus for such designation.