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The dwarf sperm whale appears to be distributed worldwide in temperate to tropical waters (Caldwell and Caldwell 1989). Sightings of these animals in the northern Gulf of Mexico occur primarily in oceanic waters (Figure 1; Mullin et al. 1991; Mullin and Fulling 2004). Dwarf sperm whales and pygmy sp...
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| Format: | Text |
| Language: | English |
| Published: |
2005
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.227.7375 http://www.nefsc.noaa.gov/nefsc/publications/tm/tm194/pdfs/256.pdf |
| Summary: | The dwarf sperm whale appears to be distributed worldwide in temperate to tropical waters (Caldwell and Caldwell 1989). Sightings of these animals in the northern Gulf of Mexico occur primarily in oceanic waters (Figure 1; Mullin et al. 1991; Mullin and Fulling 2004). Dwarf sperm whales and pygmy sperm whales (Kogia breviceps) are difficult to differentiate at sea, and sightings of either species are usually categorized as Kogia spp. Sightings of this category were documented in all seasons during GulfCet aerial surveys of the northern Gulf of Mexico from 1992 to 1998 (Hansen et al. 1996; Mullin and Hoggard 2000). The difficulty in sighting dwarf and pygmy sperm whales may be exacerbated by their avoidance reaction towards ships, and change in behavior towards approaching survey aircraft (Würsig et al. 1998). In a study using hematological and stable-isotope 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. The Gulf of Mexico population is provisionally being considered a separate stock for management purposes, although there is currently no information to differentiate this stock from the Atlantic Ocean stock(s). Additional morphological, genetic and/or behavioral data are needed to provide further information on stock delineation. |
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