Report of the stranding of a tucuxi dolphin, Sotalia fluviatilis Gervais, 1853, with remainings of nylon strings on tissue of scarred rostrum

Abstract

There are very few records of small cetaceans that survive entanglements in fishing gear. This affirmative is supported by the reduced records of dolphins that are released alive from entanglements, and also by the low frequency of healed wounds caused by interaction with fishing nets found in stranded carcasses. In this paper, the stranding of a tucuxi dolphin, Sotalia fluviatilis, in Ceará State, Brazil showing evidence that it survived a previous entanglement is reported for the first time. On november, 2000 a young male tucuxi dolphin 1300 mm long stranded in Pecém Beach, 65 km from Fortaleza city. The animal had all the teeth exposed in the upper and lower jaws, and the stomach content was a light colored paste, indicating that he was feeeding milk. During ectoscopy, recente scars cauded by fishing nets were observed along the rostrum, as well as residues of nylon strings protruding from both sides of the rostrum, close to the melon. Inserted in the tissue surrounding the rostrum, nine pieces of nylon strings (monofilament, 70mm width) were found, crossing it from side to side. Apparently, the animal was first caught in a fishing net and managed to escape, dying later in a subsequent entanglement. Debris of the fishing gear of the first entanglement remained in the animal’s tissue, after the wounds caused by the first entanglement. Debris of th fishing gear of the first entanglement remained in the animal’s tissue, after the wounds caused by the first entanglement healed. This type of record supports previous studies in the sense that small cetaceans in Ceará are highly subjected to interactions with artesanal fisheries, and urgent management actions are needed to reduce cetacean by-catch.