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Seasonal Patterns In The Abundance And Distribution Of California Cetaceans, 1991-1992, Karin A. Forney, Jay Barlow

United States Department of Commerce: Staff Publications

This study presents a detailed seasonal comparison of the abundance and distribution of cetaceans within 100-150 nmi (185-278 km) of the California coast during 1991 and 1992. The results of a shipboard line-transect survey conducted in July-November 1991 (“summer”) were compared to those from aerial line-transect surveys conducted in March-April 1991 and February-April 1992 (“winter”). Using a confidence-interval-based bootstrap procedure, abundance estimates for six of the eleven species included in the comparison exhibited significant (a = 0.05) differences between the winter and summer surveys. Pacific white-sided dolphins (Lagenorhynchus obliquidens), Risso’s dolphins (Grampus griseus), common dolphins ( …