The influence of seasonality, tide and time of activities on the behavior of Sotalia guianensis (Van Bénéden) (Cetacea, Delphinidae) in Pernambuco, Brazil

Abstract

Data on Sotalia guianensis Van Bénéden, 1864 occurrence on the beaches of Pernambuco (Northeastern Brazil) is restricted to information on stranding and on printed material from local newspapers; actual observations of such animals have not been published. This study intends to determine the use of habitat, behavioral activities and assess the relationships between environmental factors and the recorded behavior. Observations were conducted on open sea coastal areas, on the beaches of Olinda and Piedade, as well as in sheltered areas, in the ports of Recife and Suape. Monitoring was carried out every month in each area, during two consecutive days, from September 2004 to August 2005. Results corroborate that this species prefers to occupy more protected environments, the port of Recife being the main concentration area for such species. Piedade is just an exploratory area, possibly due to shark occurrence. Olinda is only occasionally used. Concentration areas seem to be used for feeding, and incidence of caudal exhibition suggests that most of the estuarine dolphin prey items are demersal. Environmental conditions (seasonality, tide and time) did not show to be significant when related to the estuarine dolphin behavior.