Estimates of abundance are available for a subset of the range of northern right whale dolphins. Across the oceanic North Pacific, Buckland et al. (1993) estimated 68,000 (CV=71%) and Miyashita (1993) estimated 307,000 northern right whale dolphins, with wide confidence limits, from sighting data, whereas Hiramatsu (1993) estimated about 400,000 dolphins for the same region based on bycatch data. All estimates have high uncertainty, and Buckland (1993) considered the two higher estimates to be positively biased. In the eastern North Pacific, the distribution of this species has been documented to vary seasonally (Forney and Barlow 1998), and abundance estimates along the U.S. West Coast have ranged from about 9,000 to 21,000 dolphins (Forney 1995, Barlow and Forney, in press). The average abundance in this region during 1996-2001 was estimated to be about 11,000 (CV = 26%); Barlow and Forney, in press).
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