Occurrence and behavior of a lone gray dolphin, Sotalia guianensis , in Northeast Brazil: when to consider a stranding?

Abstract

The gray dolphin, Sotalia guianensis , is largely distributed throughout the Atlantic tropical and subtropical coast of South and Central Americas. Stranding records are common along the Brazilian coast. Behavioral studies have been performed in restricted areas of the species distribution with few solitaries’ specimen records. From September 4th to 26th,1998, a gray dolphin spent time in a natural pool on Maracaípe, Pernambuco, Brazil. The dolphin was monitored with the purpose of understanding the reasons why it stayed there even when the environmental conditions allowed it to leave. A total of 31.17 hours of observation time was performed. The specimen left the pool on September, 26th and a dead dolphin was found three days later with similar characteristics. Even though it was not possible to define why the dolphin stayed there, it is possible to classify it as a stranding case due to the absence of human interaction. Considering the nonexistence of rehabilitation centers to small cetaceans in Brazil, on similar cases it is recommended to get biological tissue, mark and release the dolphin into an appropriated area immediately.