Post-Release Mortality of School-Size Atlantic Bluefin Tuna (Thunnus thynnus) in the U.S Recreational Troll Fishery

• Main Author: Marcek, Benjamin Jon
• Format: Text
• Language: English
• Published: W&M ScholarWorks 2013
• Subjects: Fresh Water Studies; Oceanography; Tac; North Atlantic
• Online Access: https://scholarworks.wm.edu/etd/1539617936; https://doi.org/10.25773/v5-fknv-f695; https://scholarworks.wm.edu/context/etd/article/3066/viewcontent/10632089.pdf

Atlantic bluefin tuna Thunnus thynnus (ABFT) support commercial and recreational fisheries throughout the North Atlantic Ocean. Due to heavy fishing pressure over the course of several decades, the eastern and western stocks of ABFT were overfished and the current biomass of the western stock is estimated to be approximately 19% of the biomass necessary for maximum sustainable yield. Despite a variety of management measures, including the implementation of minimum sizes and reductions of the total allowable catch (TAC) and country-specific quotas, little change was observed in the status of the western stock. The U.S. commercial and recreational ABFT fisheries are managed by the National Marine Fisheries Service (NMFS), which distributes the U.S. quota among domestic fisheries by gear type. The U.S. recreational fishery, which has historically targeted small or “school-size” (69-119cm) ABFT, is managed by open seasons, a minimum size, and bag limits (the number of ABFT allowed to be landed per vessel per day). Over the past 20 years, bag limits have been severely reduced due to decreased annual quotas, increasing the number of ABFT released each year, mostly within the school-size category. It is important, for the management of ABFT, to account for all sources of fishing mortality and the large number of releases in the recreational fishery each year could be a significant source of mortality. However, there is very little information available to assess post-release mortality of school-size ABFT in the U.S. recreational fishery. In this study, twenty pop-up satellite archival tags (PSATs) were deployed to estimate the post-release mortality of school-size ABFT captured under normal fishing conditions in the recreational fishery. PSATs recorded pressure (depth), temperature, and light data and were deployed on school-size ABFT caught using trolling methods. These tags were programmed to record data approximately every five minutes for a 31-day deployment. Nineteen tags (95%) reported to the satellites of the ...