Autonomous Platforms

Fish spawning aggregations (FSAs) consist of the temporary gathering of a large number of fishes at a specific location to spawn. Monitoring of FSA is typically conducted by divers, but surveys are often restricted to a limited area and dependent upon sea conditions, thus our knowledge of FSA dynamics is extremely limited. Fisheries independent research strives for new technology that can help remotely and unobtrusively quantify fish biomass and abundance. FSAs are challenging to observe and monitor because they are mostly found at remote locations near the shelf break , in water depths between 30 and 80 m while spawning activities occur mostly at dusk. A region of the Western Dry Rocks, approximately 10 miles southwest of Key West, Florida hosts a multitude of spawning aggregations for reef fish species of economical and recreational significance (e.g., mutton and grey snappers, permit, and other jack species). In an effort to protect these vulnerable aggregations, FWC implemented a temporary 4-month annual closure (1 April – 30 July) on the area to assess the efficacy of such measures for the long term. A first-year assessment was conducted in 2023 using AUV surveys to capture the spatial distribution and density of target species within the aggregation site. Repeating the same surveys in subsequent years will provide information on the temporal dynamics of the species and their biomass within the aggregation site following the initial closure. The evolution of these aggregation parameters will be foundational to a comprehensive evaluation of the management scheme from which to provide a case for permanent implementation.