NURSERY AREA FOR THE THREATENED GUIANA DOLPHIN, SOTALIA GUIANENSIS, ON THE NORTHEAST COAST OF BRAZIL

Abstract

Cetacean calves are considered fragile and vulnerable, especially in the first year of life. To guarantee safety and increase the likelihood of survival, females with calves use habitats with unique characteristics, called nursery areas. In the present study, we investigated whether the Guiana dolphin Sotalia guianensis, considered a threatened species in Brazil, uses the Tibau do Sul Coastal Wildlife Reserve (REFAUTS) as a nursery area. We identified the Guiana dolphins through photographs and recorded the composition of the groups during the 41-day sampling period, between 2013 and 2019. We identified 17 adults/juveniles in the company of calves, five of which were recorded in three or more years of the study. The average size of the Guiana dolphin groups (mean±SE) was 2.4±0.08 individuals, ranging from 2 to 5 individuals (n = 98). Groups with calves were recorded in every year of the study and on 53.7% of the sampling days. A total of 35.8% of the Guiana dolphin groups had calves. These results suggest that REFAUTS is an important nursery area for Guiana dolphins on the Northeast coast of Brazil.