Human-induced injuries to marine tucuxis ( Sotalia guianensis) (Cetacea: Delphinidae) in Brazil

Abstract

Guanabara Bay constitutes the most degraded habitat along the marine tucuxi dolphin (Sotalia guianensis) distribution. Considering that these mammals are found year-round in this area, where the dolphin population is estimated to be approximately 70 individuals, interactions between cetaceans and human activities are of concern. From 1995 to 2005, photo-identification techniques have been employed to study marine tucuxis in Guanabara Bay and data on the individual injuries has been collected. Seven out of 78 photo-identified and catalogued individuals presented noticeable injuries on their bodies, including cut-like wounds, skin ulceration and mutilation. Parts of fishing gear attached to the bodies of some dolphins were also observed. The concern elicited by the injuries reported here is amplified if we consider that this cetacean population is highly exposed to contaminants of known immunosuppressive action, such as organochlorine, organotin and perfluoroalkyl compounds.