Journal of
Ecology and The Natural Environment

  • Abbreviation: J. Ecol. Nat. Environ.
  • Language: English
  • ISSN: 2006-9847
  • DOI: 10.5897/JENE
  • Start Year: 2009
  • Published Articles: 407

Full Length Research Paper

Ecology and behavior of the estuarine dolphin, Sotalia guianensis (Cetacea: Delphinidae), in Sepetiba Bay, South-eastern Brazil

Mariana Freitas Nery1,2*, Sheila Marino Simão2 and Tereza Pereira2
1Instituto de Ecología y Evolución, Universidad Austral de Chile, Casilla 567, Valdivia, Chile. 2Laboratório de Bioacústica de Cetáceos, DCA, IF, Universidade Federal Rural do Rio de Janeiro, BR 465 km 7 Seropédica, RJ, 23890-000, Brazil
Email: [email protected]

  •  Accepted: 05 August 2010
  •  Published: 30 September 2010

Abstract

The dynamics of habitat utilization by Sotalia guianensis has been investigated. Between January 1997 and May 1998, 145 h of direct observations were made from a fixed location at Ponta do Zumbi on Marambaia Island, and 249 groups of dolphins were sighted. Initial and final times of the observation, approximate location, presence of calves, activities performed by the dolphins and prevailing weather conditions were recorded for all sightings. Dolphin groups were observed during all seasons of the year, and sightings occurred mainly during the late morning (9:00 - 11:59 h) and early afternoon (12:00 - 14:59 h). Dolphins exhibited a preference for the sheltered sub-areas of the bay rather than for the sub-area adjacent to the open sea. The most commonly observed aggregation of animals consisted of groups of 1 – 10 individuals. The activities performed by the dolphins were, in decreasing order of frequency of occurrence: foraging/feeding, travelling, socialization and resting. Daily and seasonal profiles of dolphins activities were dictated by many interacting factors (temporal, environmental and population characteristics), none of which could alone explain the manner in which the animals utilize the area or the organization of life cycle in the habitat.
 
Key words: Sotalia guianensis, habitat use, behaviour, group size.