STOCK DEFINITION AND GEOGRAPHIC RANGE

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1998
• Subjects: Barros; Caldwell; North Atlantic; Sperm whale
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.227.9160; http://www.nefsc.noaa.gov/nefsc/publications/tm/tm182/pdfs/43.pdf

The pygmy sperm whale (Kogia breviceps) appears to be distributed worldwide in temperate to tropical waters (Caldwell and Caldwell 1989). Sightings of these animals in the Western North Atlantic occur in oceanic waters (Mullin and Fulling 2003; SEFSC unpublished data). Pygmy sperm whales and dwarf sperm whales (K. sima) are difficult to distinguish and sightings of either species are often categorized as Kogia spp. There is no information on stock differentiation for the Atlantic population. In a recent study using hematological and stableisotope data, Barros et al. (1998) speculated that dwarf sperm whales may have a more pelagic distribution than pygmy sperm whales, and/or dive deeper during feeding bouts. POPULATION SIZE An abundance of 115 (CV=0.61) for Kogia spp. was estimated from a line-transect survey conducted from July 6 to September 6, 1998, by a ship and plane that surveyed 15,900 km of track line in waters north of Maryland (38° N) (Fig. 1; Palka et al., in review). Shipboard data were analyzed using the modified direct duplicate method (Palka 1995) that accounts for school size bias and g(0), the probability of detecting a group on the track line. Aerial data were not corrected for g(0). An abundance of 580 (CV=0.57) for Kogia spp. was estimated from a shipboard linetransect sighting survey conducted between 8