Distribution of Bottlenose Dolphins (Tursiops truncatus) on the East Coast of Isla Margarita and the Los Frailes Archipelago, Venezuela

Abstract: There have been few studies on the composition, distribution, and abundance of cetaceans in Venezuelan waters. Opportunistic stranding and sighting data revealed Tursiops, Stenella, Delphinus, and Balaenoptera edeni in the waters around Isla Margarita, Coche, Cubagua, and Los Frailes Archipelago. All of these sites are located off the northeast coast of the mainland of Venezuela in an area of coastal upwelling and complex submarine topography. The purpose of this study was to conduct a preliminary assessment of bottlenose dolphins and other cetaceans in this area. Data were gathered from June 1999 through November 2000 using a land-based platform (28 h) and a boat-based platform (26 surveys, totaling 121 h and 699 nmi). Data in relation to sea floor relief were analyzed using GIS software. Complex topographical features, such as depressions and passes located southwest of the study area, appear to limit the range of Tursiops. Bottlenose dolphins commonly occur between Punta Ballenas and Los Frailes Archipelago, where movements among those localities evidence a great plasticity in two different environments, likely to be related to prey distribution. No interspecific aggregation was recorded for bottlenose dolphins, as observed in the central coast of the country with Stenella frontalis and Tursiops truncatus. This study is the first to document cetacean habitat use around Isla Margarita and, with continued effort, will be important not only for documenting Venezuelan cetaceans but also for the assessment of potential impacts of local development, including ecotourism.


Document Type: Research article

DOI: 10.1578/AM.31.4.2005.442

Page Numbers: 442 – 446

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