Habitat use of the Guiana dolphin, <i>Sotalia guianensis</i> (Cetacea, Delphinidae), in the Caravelas River Estuary, eastern Brazil
AbstractHabitat use patterns of the Guiana dolphin (Sotalia guianensis) were assessed in the Caravelas River Estuary, eastern Brazilian coast (17°54’S, 39°21’W). During 191 surveys (2002-2004), 187 groups were sighted. The Arcview 3.1 software was used to create a GIS environment that included the distribution of dolphin sightings, a 5x5km quadrats grid, and the bathymetry of the study area. Each quadrat was characterized according to environmental variables such as depth, contour index, distance from sand banks and distance from the coastline. The Caravelas River mouth was found as the core area of the dolphins. Guiana dolphins did not use the several classes of environmental variables homogeneously, occurring more frequently in shallow waters, closer to sand banks and closer to the coastline. Also more dolphins occurred in areas with flatter bottoms and in waters with salinity ranging from 35 to 38ppm, despite dolphins being sighted in waters 14km inside the river. Dolphins used a wide range of habitat types but the Caravelas River mouth seems to propitiate the most adequate conditions for foraging strategies or concentration of prey.
LicenseAuthors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).