SE Steller sea lion tagging study needs your help

Twenty-one young Steller sea lions have been swimming around Southeast Alaska for the past 3-6 months with a variety of data-loggers and tracking devices on their heads and backs. The scientific instruments record diving depths, at-sea movements, and whether animals are on land or at sea. Through these devices the sea lions are gathering data about their feeding behaviors, and are helping researchers to evaluate two of the leading hypotheses concerning the decline of sea lions in the Gulf of Alaska and Aleutian Islands — namely the ‘junk-food’ and ‘killer whale predation’ hypotheses. Data from the sea lions will reveal the strategies they use to capture different species of prey such as pollock and herring, and whether foraging on different species makes them more or less vulnerable to predation by killer whales.

Some of the data has been transmitted from the sea lions to the researchers by satellite, but other data must be directly downloaded from the data-loggers that are still attached to 10 of the sea lions. Over the next few months the sea lions will begin their annual molt (June to September). The data-loggers will fall off during the molt. The devices are designed to float and are expected to wash ashore anywhere from Northern Lynn Canal and Frederick Sound to Glacier Bay and the outer coast.

Aerial and boat surveys will be conducted this summer to try and locate the majority of the 10 floating tags. However help from the Southeast Alaska fishing fleet and anyone combing the Southeast beaches and coast over the summer in finding the rest of the data-loggers, once they have molted off the sea lions, would be greatly appreciated. Please do not approach any sea lions on rookeries, haul-outs or elsewhere.

Once molted, the data-loggers will have a thick layer of fur on one side and may have broken antennas. Anyone locating a molted transmitter is asked to call either of the numbers above in order to receive their reward (a limited edition cap and history of the sea lion that sported the tag).

The Behaviour@Sea Project is being carried out by researchers with the North Pacific Universities Marine Mammal Research Consortium (www.marinemammal.org), with funding from NOAA and the AFDF. It is being done under NMFS permit #358-1564-06 in collaboration with the Alaska Department of Fish and Game and the Auke Bay Laboratory of the National Marine Fisheries Service. Questions can be addressed by e-mail to bas@zoology.ubc.ca.