Social Behavior of Sotalia Fluviatilis (Gervais & Deville, 1853) (Cetacea, Delphinidae), in the Northern Channel of the Amazon River, Amapá, Brazil

Abstract

Sotalia fluviatilis is known as “tucuxi” is endemic to the rivers of the Amazon basin, with aggregations of individuals at the mouths of rivers and canals, it is an almost endangered species and information about it is lacking in the state of Amapá. This study was aimed at monitoring the social behavior of S. fluviatilis in the northern channel of the Amazon River, Amapá, Brazil. Monitoring was carried out from a fixed point on the bank of the northern channel of the Amazon River, located in a Private Reserve of Natural Heritage. Ninety-six days of monitoring were carried out from a fixed point of observation, totaling 480 hours of sample effort. S. fluviatilis was frequently observed throughout the year in predominantly small groups formed mostly by two to three adult animals. Young individuals were observed in larger groups of four to six individuals, formed during activities such as feeding or for protection. Behavioral activities included slow and fast travel, which were in most cases associated with other behaviors, mainly foraging and socializing. The largest number of sightings of socialization occurred in the months of January and February, when river water levels are high. Studies on key species are essential for decision making, in order to optimize conservation strategies for this aquatic mammal in the Amapá. As a suggestion for conservation measures, it would be the distancing of vessels when they perceive a group of porpoises using the region, thus stimulating the conservation of the species.