Year-round sampling of sharks associated with specific geomorphological features of the continental shelf are uncommon but can provide details on seasonal abundance trends and habitat associations that are often lacking in coarse-scale regional surveys. Because these surveys often span wide stretches of coastline, replication at any given location is low with shark abundance and diversity insights largely focusing on the role of oceanographic factors (e.g., temperature, chlorophyll, depth, salinity). These efforts, based on traditional sampling gears including longlines and gill nets, are designed, in part, to better describe shark habitat needs and assemblage structure. Several fishery-independent shark surveys are underway in continental shelf waters of the US Atlantic and Gulf of Mexico (see Peterson et al. Yet even here, shark habitat requirements and seasonal distributions are often only broadly described, as is the function and relative value of different marine habitat types in supporting shark populations and communities. In US waters for example, where there is evidence of recent recovery in shark abundance and diversity, most species now have recognized Essential Fish Habitat (EFH) whose boundaries are established to minimize habitat impacts from commercial fishing, dredging, military operations, and other human activity. Habitat considerations are already incorporated into management policy in some countries. Understanding the habitat needs of sharks is a central component of effective management policy, especially for coastal species that are most directly exposed to human disturbances. Potential impacts to these nearby habitats should be considered when planning for sand extraction and offshore wind infrastructure.Īs a group, sharks have proven highly prone to population declines from fishing harvest and habitat loss, and increased management intervention is urgently required in many regions of the world. Overall, this study confirms that sharks can be an important component of sand shoal fish communities but suggests that deeper water immediately adjacent to shoals (as opposed to shallow shoal ridges) is more valuable to some species. Both sampling approaches documented similar single-species and community trends but longlines underestimated the shark nursery value of the region while telemetry-based community assessments are inherently biased by the number of species under active study. Water temperature, water clarity, and distance from shore were habitat factors that most strongly correlated to community composition. Moreover, the shark assemblage detected at an active sand dredge site was similar to that at nearby undisturbed sites. PERMANOVA modeling of both datasets indicate that the shark species assemblage differed more across seasons than water depth although both factors were important. A contemporaneous acoustic telemetry array detected 567 sharks from 16 species (14 in common with longlines) tagged locally and by researchers elsewhere along the US East Coast and Bahamas. limbatus) sharks being the most abundant species. Monthly longline sampling from 2012–2017 yielded 2,595 sharks from 16 species with Atlantic sharpnose ( Rhizoprionodon terraenovae), blacknose ( Carcharhinus acronotus), and blacktip ( C. This study pairs multi-year longline and acoustic telemetry surveys to reveal depth-related and seasonal patterns in a shark community associated with the largest sand shoal complex in east Florida, USA. Shoals often support unique fish assemblages but their habitat value to sharks is largely unknown due to the high mobility of most species in the open ocean. Offshore sand shoals are a coveted sand source for coastal restoration projects and as sites for wind energy development.
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