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Beluga Whale Satellite-Tagging and Health Assessments in Cook Inlet, Alaska, 1999 to 2002

Cook Inlet beluga whales, Delphinapterus leucas, are currently listed as ‘Endangered’ under the U.S. Endangered Species Act (ESA). The National Marine Fisheries Service (NMFS) began monitoring this population during the 1990s after it was added to the ESA Candidate Species list in 1988. Monitoring efforts included aerial surveys, and in 1995, the first attempts to capture and satellite-tag whales. Working with Canadian scientists and Alaska Native subsistence hunters in 1995 and 1997, tagging methods were adapted to conditions in Cook Inlet (muddy water, extreme tides, and extensive mudflats), culminating in successful capture and tracking of a whale during the summer of 1999. This was followed by three more years of capture and tagging studies during late summer. Tags were attached to 18 whales between 1999 and 2002.

Baby whale calf in front of an adult whale

A satellite tagging project was conducted from 1999 through 2003, as part of a multi-year study of summer, fall, winter, and spring movements of beluga whales in Cook Inlet. This project was a cooperative effort led by the Alaska Fisheries Science Center's Marine Mammal Laboratory and the Alaska Regional Office, collaborating with Alaska Native subsistence hunters, the Northwest Fisheries Science Center, Southwest Fisheries Science Center, Dynacare Laboratories Consumer’s Medical Lab, SeaWorld San Antonio, Alaska Veterinary Pathology Services, Joint-Base Elmendorf-Richardson, University of Alaska-Fairbanks, and the Alaska SeaLife Center.

Each beluga was tagged with a satellite-linked transmitter that recorded location data. Most tags also included a time and depth recorder which records average dive depths, dive intervals, and time at depth, while other tags recorded temperature. These data were reported to a System ARGOS receiver on a NOAA earth observation satellite passing overhead several times a day. Location of the whale is calculated from the Doppler shift in the uplink signal. The detailed position information from this study allowed biologists to follow the movements of tagged whales from their summer feeding areas to habitats occupied during fall, winter, and spring.

What we learned from these whales will help the National Marine Fisheries Service and several Alaska Native organizations in the Cook Inlet region understand the movement patterns of these animals, as well as their surfacing and diving behavior. These data were important to identifying the critical habitat areas that these endangered whales depend on given all tagged whales remained within Cook Inlet.

Health assessments conducted during this study included collection of blood serum, skin and blubber, and mucus. Skin samples provided genetic information and are used to identify individual whales and the stock that they came from. The blubber was analyzed to determine the whale's diet and contaminant loads. The blood yielded information on the general health and condition of the whale, as well as specific information on hormone levels.