Multisensor acoustic tracking benthic landers to evaluate connectivity of fishes in marine protected areas

Deep-sea fishing has been carried out on an industrial scale since the 1950s, and this has had a variety of effects on the environment and its biota. Most benthic species experience a decline in abundance or a constant decline in abundance as a result of direct disturbance of the seafloor, such as its plowing and scraping by hauled nets, with overall impacts on regional biodiversity 1. Sediment has lost some of its biogenic habitat complexity, and sessile epifauna-provided microhabitat has been destroyed or disrupted 2 and marine protected areas (MPAs) have been widely implemented to address this decline. Marine fish mobility, which is crucial for ecosystem function and is increasingly being researched with acoustic telemetry, has an impact on how well no-take MPAs (i.e., marine reserves) work in terms of protecting and repopulating fish populations 3, 4 Therefore, it is necessary to continuously monitor periodic changes in commercially exploited deep-sea ecosystems in order to gather baseline information, give accurate environmental impact assessments, and derive sound biological indicators for restoration. Using a fixed acoustic ultra-short baseline (USBL) receiver on benthic lander and miniature bidirectional acoustic tags 5, we address three key questions: How far can fish move? Does connectivity exist between adjacent MPAs? Does existing MPA size match the spatial scale of fish movements?