Estimated Bycatch of Marine Mammals and Sea Turtles in the U.S. Atlantic Pelagic Longline Fleet During 2017

The U.S. Atlantic Pelagic Longline fleet operates throughout the western North Atlantic Ocean, including along the U.S. coast from the Gulf of Mexico to New England, the waters of the Caribbean, and in international waters of the North Atlantic Ocean. The Atlantic longline fleet is defined as a Category I fishery under the Marine Mammal Protection Act, and it is also the subject of management under the Endangered Species Act due to interactions with leatherback (Dermochelys coriacea) and loggerhead (Caretta caretta) turtles. Total bycatch of marine mammals and turtles in the longline fishery was estimated for 2017 using data from the pelagic longline fishery observer program and a mandatory fishery logbook reporting program. We applied a delta-lognormal approach to estimate region specific and total annual interactions with protected species in the fishery. During 2017, there were an estimated 292.9 (206.2 – 416.1 [95% CI]) interactions with leatherback turtles and 77.1 (39.8 – 149.3 [95% CI]) interactions with loggerhead turtles. The primary marine mammals interacting with this fishery were pilot whales (Globicephala sp.) in western North Atlantic waters. Interactions were apportioned between short-finned and long-finned pilot whales based upon location and environmental parameters. The majority of interactions were with short-finned pilot whales with an estimated 132.9 (76.1 – 232.1 [95% CI]) interactions resulting in serious injury. Potential sources of bias and uncertainty in these bycatch estimates are discussed. 2020 NMFS (National Marine Fisheries Service) SEFSC (Southeast Fisheries Science Center) Submitted https://doi.org/10.25923/a3hs-ea60 Public Domain 1930