Abundance of marine mammals in waters of the U.S. southeastern Atlantic during summer 2016

In this report, we describe the results of a large vessel, visual line-transect survey conducted by the NMFS, Southeast Fisheries Science Center in U.S. waters of the U.S. Atlantic coast during the summer of 2016. The primary objective of the survey was to collect data and samples to support assessment of the abundance, habitats, and spatial distribution of cetaceans within U.S. waters. These data and resulting abundance estimates support the assessment of marine mammal stocks as required under the Marine Mammal Protection Act (MMPA) The MMPA requires that stocks of marine mammal species in U.S. waters be maintained at or above their optimum sustainable population level (OSP), defined as the number of animals which results in the maximum net productivity. To meet this requirement, the National Marine Fisheries Service (NMFS) conducts research to define stock structure, and for each stock, estimates annual human-caused mortality and potential biological removal (PBR), the maximum number of animals that may be removed from a stock due to human activities (e.g., fisheries bycatch) while allowing the stock to reach or maintain its OSP. PBR is calculated following specific criteria using the estimated minimum abundance of the stock, its maximum net productivity rate (theoretical or estimated), and a recovery factor (Barlow et al., 1995; Wade and Angliss, 1997). The NMFS is required to prepare an annual Stock Assessment Report (SAR) for each stock to update abundance, stock structure, maximum net productivity, human-caused mortality, PBR, and status (e.g., Hayes et al., 2019). This study describes the results of a summer 2016 vessel based survey and resulting abundance estimates for U.S. Western North Atlantic oceanic stocks of marine mammals.