Monitoring Pacific herring abundance with combined acoustic and optical technologies

The Prince William Sound Science Center has monitored the abundance of Pacific herring in Prince William Sound, Alaska, since 1993. The effort has expanded in the past three years because of the critical role of herring as winter-period forage for the endangered Steller sea lions. The new effort includes more seasonal coverage in Prince William Sound and expansion to herring populations around Kodiak Island. While acoustic applications for Pacific herring are well developed, species information has required expensive direct capture techniques. In the past three years, underwater cameras have been used for species identification. This application has become very effective both for identification and information on school structure and behavior.