Variação espaço-temporal de encalhes de neonatos de peixe-boi marinho (Trichechus manatus manatus Linnaeus, 1758) no litoral setentrional do estado do Rio Grande do Norte, Brasil

Abstract

The Antillean manatee (Trichechus manatus manatus Linnaeus, 1758) is an aquatic mammal whose make part of the order Sirenia and family Trichechidae. This species is herbivore and has a coastal distribution, which occurs in shallow waters such as rivers and estuaries. It is classified as “Vulnerable” by the International Union for Conservation of Nature (IUCN) and as “Endangered” by the Brazilian Red Book of Threatened Species. Consequently, the specie became as high priority conservation target in the country. The west coast of Rio Grande do Norte (RN) State and the east coast of Ceará (CE) State are the major areas of stranding occurrence of living manatee calves, which is the main threat of the specie in Brazil. This might be related to the habitat loss across the years, especially in mangrove areas by shrimp farming and saline activities. The aim of this study was to identify abiotic and anthropogenic factors that influenced stranding of manatee calves in the west coast of RN during the period of 1998 and 2018 for six cities: Tibau, Grossos, Areia Branca, Porto do Mangue, Macau, and Guamaré. In addition, it was analyzed for the same period mangrove vegetation, shrimp farming and saline areas on the Apodi-Mossoró and Piranhas-Açu rives estuaries using GIS tools. As result, it was possible to identify that anthropogenic activities such as salt production and shrimp farming intensifies deforestation of mangroves and stranding of manatee calves in both estuaries. At the same time, it was possible to notice the increase of stranding manatee calves throughout the years of living individuals records. Furthermore, the stranding calves were recorded from 2002 to 2018, being related to the rainy season of the year (during December until May). Due the lack of stranding manatee calves’ patterns it is recommended a continuous monitoring throughout the year, once that ecosystem changes seem to be related to it.