LONG-FINNED PILOT WHALE (Globicephala melas): Western North Atlantic Stock

STOCK DEFINITION AND GEOGRAPHIC RANGE There are two species of pilot whales in the western Atlantic—the Atlantic or long-finned pilot whale, Globicephala melas, and the short-finned pilot whale, G. macrorhynchus. These species are difficult to differentiate at sea; therefore, some of the descriptive material below refers to Globicephala sp., and is identified as such. The species is considered to occur from Canada to Cape Hatteras. NMFS is currently conducting research to improve the understanding of species delineation and distribution. Pilot whales (Globicephala sp.) are distributed principally along the continental shelf edge off the northeast U.S. coast in winter and early spring (CETAP 1982; Payne and Heinemann 1993; Abend and Smith 1999; Hamazaki 2002). In late spring, pilot whales move onto Georges Bank and into the Gulf of Maine and more northern waters, and remain in these areas through late autumn (CETAP 1982; Payne and Heinemann 1993). Pilot whales tend to occupy areas of high relief or submerged banks. They are also associated with the Gulf Stream wall and thermal fronts along the continental shelf edge (Waring et al. 1992; NMFS unpublished data). The long-finned pilot whale is distributed from North Carolina to North Africa (and the Mediterranean) and north to Iceland, Greenland and the Barents Sea (Sergeant 1962; Leatherwood et al. 1976; Abend 1993; Buckland et al. 1993; Abend and Smith 1999). The stock structure of the North Atlantic population is uncertain (ICES 1993; Fullard et al. 2000). Morphometric (Bloch and Lastein 1993) and genetic (Siemann 1994; Fullard et al. 2000) studies have provided little support for stock structure across the Atlantic (Fullard et al. 2000). However, Fullard et al. (2000) have proposed a stock structure that is related to sea surface temperature: 1) a cold-water population west of the Labrador/North Atlantic current, and 2) a warm-water population that extends across the Atlantic in the Gulf Stream.