NOAA’s GoPro Aquaculture Habitat Project uses video from underwater cameras to study fish abundance, behavior, and community composition on oyster aquaculture cages at shellfish farms and natural rock reef habitat in the Connecticut waters of Long Island Sound. We attached two action cameras to each study cage, one camera positioned to record across the cage top and the other with a view across two cage sides and the interface between the cage and the seafloor. We used timers to record video at 8-minute intervals hourly over a full tidal cycle. In 2018, we placed 4 study cages on both a high-density (40+) commercial oyster farm, and on featureless seafloor, respectively, to compare how cage abundance affects fish activity. To compare cages to natural structured habitat, we also constructed T-platform stands to mount cameras among boulders that provided a similar perspective to cage-mounted cameras and minimized added structure. In 2019, we compared two styles of oyster cage, shelf & bag versus stacked tray, at three oyster farms in central and western Long Island Sound. From 2017 to 2023, we monitored fish abundance on cages adjacent to the Milford commercial oyster farm to assess interannual changes in fish activity on cages. During 2022, we used GoPro cameras in stereo configuration to collect continuous video on farms and reefs in Clinton, Milford and Noank, CT that will be used to measure the body length of fish in these habitats. In 2023, we collected juvenile black sea bass from Clinton and Milford farms and reefs to assess fish condition using energy density and relative condition factor as indicators of habitat quality. To increase efficiency of processing fish for abundance estimates, we are collaborating with researchers at National Research Council-Canada to develop a machine-learning model to automate identification of the four most common temperate reef species associated with oyster cages in Connecticut.
To date, our video analysis has documented fish of all sizes and life stages using cages as habitat, including commercially and recreationally important black sea bass, scup and tautog. These temperate reef species occurred in similar or higher abundance on cages as compared to boulders. Overall, fish abundance did not differ on cages at large and small farms and or between styles of oyster cage. We have observed a variety of fish behavior associated with habitat provisioning on oyster cages including courtship/reproduction, escape from predators, feeding, grouping/schooling, sheltering and territoriality. Using 2018 data, we are estimating enhanced production of black sea bass based on the greater abundance of young-of-the-year fish we observed on oyster cages relative to the natural rock reef. We found no difference in physiological condition of fish on farms and reefs based on energy density and relative condition factor metrics. These results suggest that oyster aquaculture cages provide habitat services to fish in much the same way as natural boulder habitat and that oyster farms may act like artificial reefs providing structured habitat for fish on otherwise featureless seafloor.