WHITE-BEAKED DOLPHIN (Lagenorhynchus albirostris): Western North Atlantic Stock

• Main Authors: Stock Definition, Geographic Range
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1997
• Subjects: Barents Sea; Greenland; Mikkelsen; Reeves; Lagenorhynchus albirostris; North Atlantic; Northwest Atlantic; White-beaked dolphin
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.433.1749; http://www.nefsc.noaa.gov/publications/tm/tm114/pdfs/92.pdf

White-beaked dolphins are the more northerly of the two species of Lagenorhynchus in the Northwest Atlantic (Leatherwood et al. 1976). The species is found in waters from southern New England, north to western and southern Greenland and Davis Straits (Leatherwood et al. 1976; CeTAP 1982), in the Barents Sea and south to at least Portugal (Reeves et al., in press). Differences in skull features indicate that there are at least two separate stocks, one in the eastern and one in the western North Atlantic (Mikkelsen and Lund 1994). No genetic analyzes have been conducted to distinguish the stock structure. In waters off the northeastern U.S. coast, white-beaked dolphin sightings have been concentrated in the western Gulf of Maine and around Cape Cod (CeTAP 1982). The limited distribution of this species in U.S. waters has been attributed to opportunistic feeding (CeTAP 1982). Prior to the 1970's, white-sided dolphins (L. acutus) in U.S. waters were found primarily offshore on the continental slope, while white-beaked dolphins were found on the continental shelf. During the 1970's, there was an apparent switch in habitat use between these two species. This shift may have been a result of the increase in sand lance in the continental shelf waters (Katona et al. 1993; Kenny et al. 1996). POPULATION SIZE The total number of white-beaked dolphins in U.S.and Canadian waters is unknown, although one abundance estimate is available for part of the known habitat in U.S. waters, and two estimates are from Canadian waters (Table