Ecological niche segregation within a community of sympatric dolphins around a tropical island

• Published in: Marine ecology. Progress series (Halstenbek) 2011-07, Vol.433, p.273-288
• Main Authors: Kiszka, Jeremy, Simon-Bouhet, Benoit, Martinez, Ludivine, Pusineri, Claire, Richard, Pierre, Ridoux, Vincent
• Format: Article
• Language: English
• Subjects: Aquatic communities; Aquatic habitats; Dolphins; Ecological niches; Ecology, environment; Ecosystems; Foraging; Habitat preferences; Isotopes; Lagenodelphis hosei; Life Sciences; Marine; Peponocephala electra; Signatures; Species; Stenella longirostris; Tursiops aduncus; Whales
• ISSN: 0171-8630; 1616-1599
• DOI: 10.3354/meps09165

Investigating ecological segregation among organisms of a given community is challenging, especially when these organisms share similar patterns of distribution, and similar size and morphology. Around the island of Mayotte, a diversified community of at least 4 sympatric delphinids is present year round within a very restricted range: the Indo-Pacific bottlenose dolphinTursiops aduncus, the spinner dolphinStenella longirostris, the pantropical spotted dolphinS. attenuata, and the melon-headed whalePeponocephala electra. In addition, the Fraser’s dolphinLagenodelphis hoseimakes temporary incursions into peri-insular waters as well. This study aims to assess niche segregation among this tropical dolphin community. We hypothesized that each species occupies its own distinct niche defined by the following axes: habitat, resources and time. We analysed habitat in relation to physiography, behavioural budgets and C and N stable isotope values from skin and blubber samples for each species. The results highlighted that habitat and behavioural budgets were relatively distinct among species, with few exceptions. However, in those species living on the outer reef slope where habitat and behaviour were not well discriminated, stable isotope analyses confirmed that species have different trophic levels (mostly reflected through δ15N values) or foraging habitat (mostly reflected through δ13C values). This study confirms that the use of multiple methodologies (habitat, behaviour and feeding ecology studies) help in discerning ecological niche segregation, especially when examining closely related species within a common restricted range.