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1 April 2015 Possible Stock Structure of Coastal Bottlenose Dolphins off Baja California and California Revealed by Photo-Identification Research
R.H. Defran, Marthajane Caldwell, Eduardo Morteo, Aimée R. Lang, Megan G. Rice, David W. Weller
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Abstract

Boat-based photo-identification research has been carried out on bottlenose dolphins in eastern North Pacific coastal waters off northern Baja California, Mexico and southern and central California, USA from 1981 to 2001. Within these waters, bottlenose dolphins routinely travel back and forth between coastal locations while generally staying within a narrow corridor extending only 1–2 km from the shore. Inter-area match rates for 616 dolphins photo-identified between 1981–2000 in four California coastal study areas (CCSAs) of Ensenada, San Diego, Orange County and Santa Barbara averaged 76%. To explore possible southern range limits for these dolphins, photo-identification surveys were carried out in the coastal waters off San Quintín, Baja California, Mexico between April-August 1990 (n = 8 surveys) and July 1999 to June 2000 (n = 12 surveys). The 207 individual dolphins identified off San Quintín were compared to the 616 dolphins identified in the CCSAs. The inter-area match rate between San Quintín and the CCSAs was 3.4% (n = 7 dolphins). This low rate contrasts sharply with the much higher average match rate of 76% observed between the CCSAs. These differences in match rates suggest that both a California coastal stock and coastal Northern Baja California stock may exist, with only a limited degree of mixing between them.

© Southern California Academy of Sciences, 2015
R.H. Defran, Marthajane Caldwell, Eduardo Morteo, Aimée R. Lang, Megan G. Rice, and David W. Weller "Possible Stock Structure of Coastal Bottlenose Dolphins off Baja California and California Revealed by Photo-Identification Research," Bulletin, Southern California Academy of Sciences 114(1), 1-11, (1 April 2015). https://doi.org/10.3160/0038-3872-114.1.1
Published: 1 April 2015
JOURNAL ARTICLE
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