Incorporating Migration and Local Movement Patterns into Management Strategies for Spiny Dogfish (Squalus acanthias)

• Main Authors: Cudney, Jennifer L., NC DOCKS at East Carolina University
• Language: English
• Published: 2023
• Subjects: Acoustic telemetry;Contingent; Northwest Atlantic; spiny dogfish; Squalus acanthias
• Online Access: http://libres.uncg.edu/ir/ecu/f/0000-embargo-holder.txt

The overall purpose of this dissertation is to increase understanding of migration and movement behaviors associated with a highly migratory elasmobranch species. In particular, I seek to determine whether sufficient evidence exists to warrant the separation of the northwest Atlantic Spiny Dogfish (Squalus acanthias) into separate management units. These management units are not genetically distinct, but rather would be based on unique behaviors adopted by hypothesized groups of dogfish that connect reproductive, feeding, and overwintering grounds (“contingents”). This dissertation includes an introductory chapter that introduces the reader to the Spiny Dogfish resource and recent management actions undertaken, followed by a chapter that provides technical and design recommendations based on a meta-analysis and a case study, which address the challenges of conducting behavioral research in dynamic environments through the use of acoustic telemtry. Approximately 30 percent of papers reviewed had no details on design specifications. Meta-analyses suggest that more fish were redetected when more acoustic equipment was deployed for longer periods of time, exemplifying the need for robust equipment that can withstand the rigors of an offshore, dynamic environment. In particular, we found that a heavy anchor, a subsurface float holding a mooring line, and a highflier-float system produced the best results in our case study. New behavioral information, derived from an analysis of data collected through a long-term conventional mark-recapture program and a multi-year acoustic tagging program, suggest that spiny dogfish tagged off North Carolina in overwintering grounds routinely make seasonal migrations to summer feeding habitats off southern New England (specifically, Massachusetts), but do not necessarily follow the same pathway each year. Sharks were often not detected on acoustic receivers for lengthy periods of time, and mark-recapture data indicated extremely lengthy times at liberty (1,000+ days). Spiny Dogfish ...