Seasonal distribution and habitat use of the common thresher shark (Alopias vulpinus) in the western north atlantic ocean inferred from fishery-dependent data

Abstract

—Improved understanding of the seasonal distribution, habitat use, and fishery interactions of the common thresher shark (Alopias vulpinus) in the western North Atlantic Ocean (WNA) is required for future management. We compiled and analyzed 3478 fishery-dependent capture records in the WNA between 1964 and 2019 to examine dynamics by sex and life stage (i.e., young of the year, juvenile, and adult). Sharks were captured over a broad geographic range from the Gulf of Mexico to the Grand Banks, primarily in continental shelf waters shallower than 200 m. Seasonal north–south movements along the east coasts of the United States and Canada were observed for all life stages and both sexes, with individuals generally occurring at more northerly latitudes in the summer and more southerly latitudes in the winter. Distinct areas of more frequent capture in fisheries were identified for all life stages throughout their range. Common thresher sharks were observed in waters with sea-surface temperatures of 4–31°C, most commonly of 12–18°C. The results of this study will help to identify essential fish habitat for each life stage of common thresher sharks along the U.S east coast and to develop management measures for the WNA population.