The common thresher (Alopias vulpinus) is listed by the IUCN on its Red List of Threatened Species as Vulnerable to extinction globally, due to severe, continued declines in their populations around the world.
A. vulpinus is widely distributed and has a circumglobal in distribution. It can be found in tropical to cold-temperate seas, but is most common in temperate waters (Compagno 2001) and most abundant in waters up to 40 or 50 miles offshore (Strasburg 1958; Gubanov 1972; Moreno et al. 1989; Bedford 1992). Genetic studies and comparisons of biological characteristics (fecundity and length at maturity) of specimens from different regions of the world show that although migratory, A. vulpinus appears to exhibit little to no immigration and emigration between geographic areas; namely between the Pacific and northwest Atlantic populations (Gubanov 1972; Morenoet al. 1989; Bedford 1992; Trejo 2004). In the absence of records of transatlantic migrations a single northeast Atlantic and Mediterranean stock of A. vulpinus is assumed (ICES 2007).In the Northeast Atlantic, A. vulpinus has been recorded from Norway to the Mediterranean and Black Seas, and off Madeira and the Azores, with juveniles caught in UK waters in the English Channel and southern North Sea (Ellis 2004).
Alopias spp.are caught and killed in both target and bycatch fisheries in domestic waters and the high seas globally. Catch is often unmanaged or only managed over part of their range. Alopias spp. fins are an important component of the global shark fin trade, with the last comprehensive study of the trade identifying them as accounting for approximately 2.3 % of sharks in the Hong Kong market. This is equivalent to up to four million thresher sharks per year (Clarke et al. 2006 A and B).They all exhibit particularly low productivity and growth rates meaning they have a high susceptibility to anthropogenic pressure and show slow recovery from overexploitation.