SEAFWA 2018

AUTHORS: Jayne M. Gardiner, New College of Florida; Tonya R. Wiley, Havenworth Coastal Conservation; Joel A. Beaver, New College of Florida

ABSTRACT: NMFS is mandated to include Essential Fish Habitat in all Fishery Management Plans, considering all life stages of a species, not just those that are being exploited. The blacktip shark, Carcharhinus limbatus, is the dominant species captured in the directed large coastal shark fishery in the Gulf of Mexico. NMFS has managed this species since 1991, initially as part of the Large Coastal Shark Complex, and individually since 2006. Since that time, attempts have been made at quantifying blacktip shark nursery areas, which represent EFH for neonates and juveniles. However, without clear criteria for defining nurseries, EFH designations have remained broad, currently encompassing the entire US Gulf coastline. Heupel et al. (2007) proposed that nursery areas be defined based not only on the presence of juvenile sharks, but also based on site fidelity and the tendency of animals to use habitats repeatedly across several years. Low tag-recapture rates hamper efforts to define nurseries using conventional tags. Acoustic telemetry has provided important information on individual nurseries, but short battery life and the limited spatial/temporal coverage of receiver arrays have traditionally limited the relevance of this tool at a management scale. Here, we present data on two blacktip shark nurseries on the Gulf coast of Florida as case studies, demonstrating how recent advances in tag technology and the emergence of regional and Gulf-wide cooperative telemetry arrays enable assessments of long-term patterns of natal philopatry and rates of movement between nurseries, behaviors that influence population connectivity and stock structure on a Gulf-wide scale.