Analysis of stranding data to support estimates of mortality and serious injury in common bottlenose dolphin (Tursiops truncatus truncatus) stock assessments for the Atlantic Ocean and Gulf of Mexico

The common bottlenose dolphin (Tursiops truncatus truncatus, hereafter referred to as bottlenose dolphin(s) or dolphin(s)), occurs in estuarine, coastal, continental shelf, and oceanic waters of the western North Atlantic (WNA) and Gulf of Mexico (GMx). In the WNA, distinct morphological forms have been identified: a larger, more robust “offshore” morphotype occurring in deep waters of the continental shelf and slope from Florida's east coast to Canada, and a smaller “coastal” morphotype present in estuarine, coastal, and shelf waters from Florida to approximately Long Island, New York (Mead and Potter 1995; Torres et al. 2003; Rosel et al. 2009; Hayes et al. 2017). The offshore morphotype is considered a single separate stock (Offshore Stock). The coastal morphotype, however, comprises at least 11 bay, sound, and estuary (BSE) stocks in WNA waters from Florida through Virginia, and five coastal stocks that abut the BSE stocks (Hayes et al. 2017) (Figures 1–3). Many of the BSE stocks also occur in nearby coastal waters resulting in spatio-temporal overlap with coastal migratory stocks (e.g., Speakman et al. 2010; Hayes et al. 2017; Balmer et al. 2018; Lyssikatos and Garrison 2018). Additionally, spatio-temporal overlap occurs between different coastal migratory stocks in the WNA (e.g., Hayes et al. 2017; Lyssikatos and Garrison 2018). In the northern GMx (i.e., U.S. GMx), the coastal morphotype comprises at least 31 BSE stocks from Texas through Florida's west coast and three coastal stocks that abut the BSE stocks. As described for the WNA, there is known spatio-temporal overlap in distribution between some stocks in BSE and coastal waters (e.g., Balmer et al. 2016; Hayes et al. 2017; Mullin et al. 2017; Wells et al. 2017). 2019 NMFS (National Marine Fisheries Service) SEFSC (Southeast Fisheries Science Center) Submitted https://doi.org/10.25923/jt1x-jv75 Public Domain 1864