Stable isotopes differentiate bottlenose dolphins off west-central Florida

作者：Barros Nelio B^*; Ostrom P H; Stricker C A; Wells R S

来源：Marine Mammal Science, 2010, 26(2): 324-336.

DOI：10.1111/j.1748-7692.2009.00315.x

• bottlenose dolphins
• Tursiops truncatus
• stable isotopes
• population assignment
• group membership
• strandings
• Florida
• Gulf of Mexico

P>Distinguishing discrete population units among continuously distributed coastal small cetaceans is challenging and crucial to conservation. We evaluated the utility of stable isotopes in assessing group membership in bottlenose dolphins (Tursiops truncatus) off west-central Florida by analyzing carbon, nitrogen, and sulfur isotope values (delta 13C, delta 15N, and delta 34S) of tooth collagen from stranded dolphins. Individuals derived from three putative general population units: Sarasota Bay (SB), nearshore Gulf of Mexico (GULF), and offshore waters (OFF). Animals of known history (SB) served to ground truth the approach against animals of unknown history from the Gulf of Mexico (GULF, OFF). Dolphin groups differed significantly for each isotope. Average delta 13C values from SB dolphins (-10.6 parts per thousand) utilizing sea grass ecosystems differed from those of GULF (-11.9 parts per thousand) and OFF (-11.9 parts per thousand). Average delta 15N values of GULF (12.7 parts per thousand) and OFF (13.2 parts per thousand) were higher than those of SB dolphins (11.9 parts per thousand), consistent with differences in prey trophic levels. delta 34S values showed definitive differences among SB (7.1 parts per thousand), GULF (11.3 parts per thousand), and OFF (16.5 parts per thousand) dolphins. This is the first application of isotopes to population assignment of bottlenose dolphins in the Gulf of Mexico and results suggest that isotopes may provide a powerful tool in the conservation of small cetaceans.

• 出版日期2010-4