406 
78W 76W 74W 72°W 70°W 
Fishery Bulletin 118(4) 
78W 76W 74W 72°W 70°W 
Figure 5 
Distribution of young-of-the-year common thresher sharks (Alopias vulpinus) by season in the 
western North Atlantic Ocean between 1964 and 2019. The number of capture records (Rec) in 
each grid cell (0.5° x 0.5°) is natural log transformed. One record of a capture in the Gulf of Mexico 
is not presented because it may have been a misidentification. The 200-m depth contour delineates 
the boundary of the continental shelf. 
distributed at depths <200 m in the continental shelf 
waters in the WNA but that its range seasonally extends 
farther offshore, closer to the northern edge of the Gulf 
Stream along the Scotian Shelf and Grand Banks (Fig. 4) 
(Castro, 2011). Although higher rates of observer coverage 
in coastal fisheries (NMFS, 2019b) would contribute to 
more frequent capture of common thresher sharks in con- 
tinental shelf waters, their limited occurrence in the 
extensive and fairly well-monitored pelagic longline fish- 
eries in offshore waters of the United States and Canada 
