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The Utility of Underwater Video in a Fisheries-Independent Reef Fish Survey

Dawn Glasgow, SCDNR

23 February 2018

Stock assessments indicate many valuable reef fish species are declining, often due to past or current overfishing. Stock assessments for many valuable reef fish species in southeastern U.S. Atlantic use several data sources to indicate abundance levels, including a fishery-independent chevron trap survey for members of the snapper-grouper complex.  However, catchability for trap surveys vary for many reasons such as gear selectivity, environmental conditions, and/or inter- and intraspecific relationships. Underwater video has become a popular method for assessing reef fish populations around the world as a passive and non-extractive gear to provide researchers with abundance estimates. Recent research has utilized trap catches and complementary video to provide a more comprehensive view of abundance and community patterns of reef fish and how the environment, or habitat, play a role in these patterns. The combined survey has also been used to examine predator-prey dynamics within traps that may influence the relative abundance of large predatory fish that cannot be determined by trap catch alone. Underwater video provides a unique look at interesting behaviors, species interactions, and the ecosystem rather than just the fish, and provides much needed insight that can help guide our future efforts to manage and conserve these communities, and increase fisheries sustainability.