Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2021
Erindi/veggspjald / Talk/poster E85
Höfundar / Authors: Filipa Samarra (1), Asunción Borrell (2), Alex Aguilar (2) and Gísli Víkingsson (3)
Starfsvettvangur / Affiliations: 1. University of Iceland, 2. University of Barcelona, 3. Marine and Freshwater Research Institute
Kynnir / Presenter: Filipa Samarra
Niche partitioning among sympatric species occurs to decrease competition for resources. Here, we investigate the feeding ecology of four of the most common odontocetes occurring in Iceland. Using stranding, bycatch and/or biopsy samples spanning approximately 30 years we investigate within and between species differences in stable isotopic signatures of carbon and nitrogen in relation to year of sampling, length, sex, age class and differences between stranded and bycatch/biopsy samples. We find evidence of niche segregation but also some extent of overlap between species, suggesting that largely these species avoid competition by either targeting different resources or by possibly consuming the same resource in different proportions. Temporal trends in carbon isotopic signatures indicative of the Suess effect are observed but the rate of change through time varies with species. Changes in nitrogen isotopic signatures between age classes were observed. Stranded white-beaked dolphins showed higher carbon and nitrogen isotope ratios than bycaught dolphins, suggesting that bycaught individuals might have with a diet that is not representative of the whole population or, alternatively, that stranded individuals were under nutritional stress or poor health condition or might have shifted to alternative prey. This study provides the first integrated assessment of odontocete feeding ecology in Iceland, which will contribute to measure the effects of future environmental changes.