HOPE report

Number: 24-004

Preliminary analysis for playback experiment of predator calls to pinnipeds /Learning method for acoustic analysis

Report: Mizuguchi Daisuke

Date: 2012/6/8 - 2012/9/26

The conflict between fishery and pinnipeds is serious problem in Japan and also some other countries. Playback sounds to pinnipeds which they avoid is one of the methods expected to be able to keep them away from fishing net. Especially, predator sounds seem to be effective because it would take much more time for pinnipeds to get accustomed to the sounds. Using sounds never damage or kill pinnipeds so this method can be used also to the species that is endangered but has conflict with fishery. In this year, we observed in-air and underwater vocalization in three pinnipeds (Steller sea lion, California sea lion, and Harbor seals), and also measured the background noise level as fundamental information for playback experiment in Tatoosh Islands and Sea Lion Rocks in Seattle, and Astoria, Oregon. Sea lions made bark or roar sounds continuously and frequently both in-air and underwater, so their vocal behavior seemed to be a good index to check their reaction to the playback sounds. I also learned how to analyze the acoustic data, and analyzed underwater vocalization of ribbon seals in the Bering Sea to know the seasonal and diurnal changes of their vocalization, and what kind of factor affects their vocal behavior.

Tatoosh Island, Seattle

At the port of Astoria, Oregon. A labeled individual (left)

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