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 identify to the species level at sea; therefore, some of the descriptive material below refers to Globicephala sp., and is identified as such. The species boundary is considered to be in the New Jersey to Cape Hatteras area. Sightings north of this area are likely G. melas. Pilot whales (Globicephala sp.) are distributed principally along the continental shelf edge in the winter and early spring off the northeast USA coast, (CETAP 1982; Payne and Heinemann 1993). 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). In general, pilot whales occupy areas of high relief or submerged banks. They are also associated with the Gulf Stream north wall and thermal fronts along the continental shelf edge (Waring et al. 1992; NMFS unpublished data). 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 correlated 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. POPULATION SIZE The total number of long-finned pilot whales off the eastern USA and Canadian Atlantic coast is unknown, although ten estimates from selected regions of the habitat do exist for select time periods. Sightings were almost exclusively in the continental shelf edge and continental slope areas (Figure 1). Two estimates were derived from catch data and population models that estimated the abundance of the entire stock. Seven seasonal estimates are available from selected regions in USA waters during spring, long-finned and short-finned pilot whales are difficult to identify at sea, seasonal abundance estimates were reported for Globicephala sp., both long-finned and short-finned pilot whales. One estimate is available from the Gulf of St. Lawrence. Mitchell (1974) used cumulative catch data from the 1951-61 drive fishery off Newfoundland to estimate the initial population size (ca. 50,000 animals).