Tue, Aug 03, 2021:On Demand
Background/Question/Methods
Many residents in the Turks and Caicos Islands rely on commercial fishing as a main source of revenue and sustenance. Increasing efficiency of catch rates of fish such as Ocyurus chrysurus may relieve pressure on the historically overfished lobster and conch industry in the area, increase economic growth in commercial fishing, and add an alternative source for food security. Activity levels and foraging behavior have been linked to individual vulnerability to fishing. Studying this behavior has been linked to the increase in catch in certain fish species. Foraging behavior, bite duration, and conspecific density especially contribute to the overall vulnerability of fish to angling. Through the use of Baited Remote Underwater Video (BRUVs), this study analyzed the relationship between active foraging behavior (biting, circling, and hovering) and active sessions of individuals (the count of individual entrances into a frame) with reef depth (10m and 20m). Behavioral analysis was collected for foraging behaviors for each individual by start and end times of behavior in seconds. Individual active sessions were recorded by entrance and exit time of individual fish in the video frame. A total of 2,555 minutes of video was analyzed for this project
Results/Conclusions The results found that individuals at 20m spent significantly more time displaying active foraging behavior (biting, circling, and hovering) than at 10m. Bite behavior occurred significantly more at 20m than 10m however, the bite behavior duration between depths was not significantly different. Finally, more individual active sessions were recorded at 20m than at 10m. 4326 individual active sessions were recorded at 20m and 2550 individual active sessions were recorded at 10m. However, the difference between depths was not found to be statistically significant. Our study suggests that targeting O. chrysurus fish at depths of 20m would increase catch efficiency due to a higher conspecific density and significantly more time displaying active foraging behavior. This study is important as there is little behavioral research on O. chrysurus in the context of angling vulnerability or in conjunction with potential catch efficiency.
Results/Conclusions The results found that individuals at 20m spent significantly more time displaying active foraging behavior (biting, circling, and hovering) than at 10m. Bite behavior occurred significantly more at 20m than 10m however, the bite behavior duration between depths was not significantly different. Finally, more individual active sessions were recorded at 20m than at 10m. 4326 individual active sessions were recorded at 20m and 2550 individual active sessions were recorded at 10m. However, the difference between depths was not found to be statistically significant. Our study suggests that targeting O. chrysurus fish at depths of 20m would increase catch efficiency due to a higher conspecific density and significantly more time displaying active foraging behavior. This study is important as there is little behavioral research on O. chrysurus in the context of angling vulnerability or in conjunction with potential catch efficiency.