Structure of a toothed cetacean community around a tropical island (Mayotte, Mozambique Channel)

Jeremy Kiszka (1) , Peter Ersts (2) , Vincent Ridoux (1)

1 LIENSs - LIttoral ENvironnement et Sociétés
2 AMNH - American Museum of Natural History [New York, USA] = Musée américain d'histoire naturelle [New York, USA]

We describe the structure of a toothed cetacean community around the island of Mayotte (South-West Indian Ocean, 45°10'E, 12°50'S), using data collected from small boat-based surveys conducted between July 2004 and June 2006. In all, 16 odontocete species were recorded. Diversity (Shannon-Weaver index) was particularly high along the outer slope of the barrier reef. Patterns of spatial distribution underscore the existence of three main cetacean habitat types: the inner lagoon (Indo Pacific bottlenose dolphin Tursiops aduncus, and humpback dolphin Sousa chinensis), the outer reef slope (Spinner dolphin Stenella longirostris, Pantropical spotted dolphin S. attenuata and melon-headed whale Peponocephala electra) and oceanic waters deeper than 500 m (e.g. Blainville's beaked whale Mesoplodon densirostris). Group characteristics were highly variable among species, with oceanic small delphinids characterised by larger group sizes than strictly coastal and non-delphinid oceanic species. The outer slope of the barrier reef appears to be of primary importance in terms of density and diversity of odontocetes around Mayotte. Results support the hypothesis that a number of cetacean species, particularly several delphinid species, are dependant on coral reef complexes.

Domaines: Ecosystèmes

Jeremy Kiszka, Peter Ersts, Vincent Ridoux. Structure of a toothed cetacean community around a tropical island (Mayotte, Mozambique Channel). African Journal of Marine Science, 2010, pp.543-551. ⟨hal-00606322⟩