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Genetic differentiation among coastal and offshore common bottlenose dolphins, Tursiops truncatus , in the eastern North Pacific Ocean
Author(s) -
LowtherThieleking Janet L.,
Archer Frederick I.,
Lang Aimee R.,
Weller David W.
Publication year - 2015
Publication title -
marine mammal science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.723
H-Index - 78
eISSN - 1748-7692
pISSN - 0824-0469
DOI - 10.1111/mms.12135
Subject(s) - microsatellite , bottlenose dolphin , stock (firearms) , submarine pipeline , ecotype , geography , fishery , mitochondrial dna , genetic diversity , biology , ecology , oceanography , allele , genetics , population , geology , demography , archaeology , sociology , gene
Common bottlenose dolphins ( Tursiops truncatus ) are found worldwide in temperate and tropical regions, often occurring as distinct coastal and offshore ecotypes. Along the west coast of the United States, two stocks are recognized for management based on morphological and photo‐identification studies: a California coastal stock, estimated at 450–500 individuals, and a California/Oregon/Washington offshore stock of about 1,000 animals. This study is the first to analyze genetic differentiation between these stocks. We examined both the hypervariable portion of the mitochondrial DNA (mt DNA ) control region and fifteen microsatellite markers for coastal ( n = 64) and offshore ( n = 69) dolphins. Significant genetic differentiation was found between the two stocks for mt DNA ( Φ ST = 0.30, P < 0.001; F ST = 0.14, P < 0.001) and microsatellite loci ( F ST = 0.19, P < 0.001). Coastal dolphins had less genetic diversity than offshore dolphins. Further substructuring within the offshore stock was not detected. The level of genetic differentiation between the coastal and offshore dolphins is consistent with long‐term separation and reinforces recognizing them as separate stocks. These findings are particularly important for management of the smaller, less genetically diverse, coastal stock that is vulnerable to a variety of anthropogenic threats.