Bone lesions in Sotalia fluviatilis (Cetacea) as a consequence of entanglement: Case report

RESUMO

The objective of the present study was to describe a set of lesions caused by entanglement of Sotalia fluviatilis accidentally captured by gillnet on July, 23, 1995, in the Northern Rio de Janeiro State (21º37'S-041º01'W), Southeastern of Brazil. The specimen presented lacerated lesions of the skin and subcutaneous tissue around the posterior extremity of the rostrum. Nylon twines were found associated to these lesions. Bone and teeth lesions were also observed in the underlying area and affected the maxillaries, pre-maxillaries and mandibles. The lesions were likely caused by non-lethal entanglement in fishing gears. Abnormalities in the growth layer pattern of the damaged teeth between the third and sixth growth layers suggest that this encounter had taken place when the specimen was around three years old. The data indicate that non-lethal encounters with fishing gears may cause serious health problems to small cetaceans and reduce their lifetime. This is the first description of fisheries-related chronic lesions in S. fluviatilis