Stable isotope analysis in two sympatric populations of bottlenose dolphins Tursiops truncatus: evidence of resource partitioning?

Skin and muscle from 43 bottlenose dolphins (38 juveniles/adults, 5 calves) stranded in NW Spain were analysed to determine whether stable isotope ratios (δ 13 C and δ 15 N) could be used to assess dietary variation, habitat segregation and population substructure. Results were compared with publish...

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Bibliographic Details
Published in:Marine biology 2011-05, Vol.158 (5), p.1043-1055
Main Authors: Fernández, Ruth, García-Tiscar, Susana, Begoña Santos, M., López, Alfredo, Martínez-Cedeira, Jose A., Newton, Jason, Pierce, Graham J.
Format: Article
Language:English
Subjects:
Animal and plant ecology
Animal behavior
Animal, plant and microbial ecology
Aquatic mammals
Biological and medical sciences
Biomedical and Life Sciences
Body size
Competition
Delphinidae
Dolphins
Dolphins & porpoises
Freshwater & Marine Ecology
Fundamental and applied biological sciences. Psychology
Isotope analysis
Isotopes
Life Sciences
Mammalia
Marine
Marine & Freshwater Sciences
Marine biology
Mass spectrometry
Microbiology
Oceanography
Original Paper
Physiological aspects
Prey
Resource partitioning
Sea water ecosystems
Stable isotopes
Synecology
Trophic levels
Tursiops truncatus
Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
Zoology
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Summary:Skin and muscle from 43 bottlenose dolphins (38 juveniles/adults, 5 calves) stranded in NW Spain were analysed to determine whether stable isotope ratios (δ 13 C and δ 15 N) could be used to assess dietary variation, habitat segregation and population substructure. Results were compared with published stomach contents data. Stable isotope ratios from 17 known prey species were also determined. Isotope ratios of the main prey (blue whiting, hake) varied significantly in relation to fish body size. Dolphin calves showed significant heavy isotope enrichments compared to adult females. Excluding calves, δ 15 N decreased with increasing dolphin body size, probably related to an ontogenetic shift in diet towards species at lower trophic levels, e.g. on blue whiting as suggested by stomach content results. Bottlenose dolphins were divided into two putative populations (North, South) based on previous genetic studies, and values of δ 13 C and δ 15 N differed significantly between these two groups, confirming the existence of population structuring.
ISSN:0025-3162
1432-1793
DOI:10.1007/s00227-011-1629-3