Use of space and temporal distribution of Trichechus manatus manatus Linnaeus in the region of Sagi, Rio Grande do Norte State, Brazil (Sirenia, Trichechidae)

Abstract

The marine manatee Trichechus manatus manatus Linnaeus, 1758 is endangered in the Brazilian Atlantic coast due to indiscriminate hunting practiced in the past, and to the low reproductive rate of the species. This work studies its use of space and temporal occurrence in the coastal area of Sagi, Northeastern Brazil. Daily observations from the beach of the animals in the sea were made during daytime from 1990 through 1993. The presence of reefs covered with marine algae is a determinant factor in the occurrence of the manatee. They were sighted feeding on algae that grow over the reefs close to beaches that were of high energy during high tide. The range used by manatees shifted according to tide. They occur in depths of 0.4 to 3.8 m; the distance from the beach varies according to the tide level. They show marked seasonality of occurrence, with higher frequencies in December - January and lowest in June - July. Two possible causes of the seasonal occurrence are discussed. Sagi is important for the conservation of the species in Northeastern Brazil as feeding and reproductive grounds.