Interações de cetáceos (subordem Odontoceti) com a pesca artesanal no Brasil

Abstract

Dolphins are aquatic animals adapted to living in environments such as seas, estuaries, and rivers, and they feed on fish, cephalopods, and crustaceans. These animals interact with fishing activities, which result in either positive or negative interactions for both fishermen and the animals themselves. These interactions have been reported along the entire Brazilian coast, which is home to approximately 1.084 million artisanal fishermen operating along over 8,000 km of coastline. Therefore, for the conservation of dolphin species, it is essential to analyze the types of interactions that exist between them and fishing, so that this recognition enables the promotion of actions and the development of conservation strategies, mainly directed towards species most threatened by fishing activities. In seeking to investigate interactions between cetaceans and artisanal fishing, this dissertation consists of two chapters. Considering the importance of efforts to assess existing interactions between small cetaceans and artisanal fishing activity along the Brazilian coast and inland river environments, the first manuscript aimed to: a) compile studies considering artisanal fishing and its interactions with small cetaceans in Brazil; b) classify interactions between cetaceans and artisanal fishing recorded in Brazil; and c) identify dolphin species recorded in the studies. For this purpose, a national bibliometric study with a predominantly exploratory-descriptive approach was conducted. ArcGIS cloud-based analysis and mapping solution were used for data analysis. Results revealed 36 publications addressing artisanal fishing and interactions with cetaceans. In these studies, 12 types of interactions between cetaceans and fishing activity along the Brazilian coast were identified, of which only seven (Entanglement, Collision, Netting, Harpooning, Theft, Ambush, and Cooperation) matched descriptions available in the literature, while the others were included and described based on analyses of reports obtained from the studies reviewed. The newly identified interactions were: Disturbance, Predation, Discard, Startle, and Signaling. Furthermore, the compiled studies encompassed 43.2% (n = 16) of the 37 odontocete species reported for Brazil. The dolphin species most mentioned by fishermen were Sotalia guianensis (n = 14; 21.2%), Tursiops truncatus (n = 12; 18.2%), Pontoporia blainvillei (n = 8; 12.1%), Inia geoffrensis (n = 7; 10.6%), and Sotalia fluviatilis (n = 5; 7.6%). Thus, it can be considered that studies focusing on understanding interactions between cetaceans and artisanal fishing can generate data that contribute to establishing guidelines in management plans and the conservation of cetacean species and coastal and riverine ecosystems where these species occur. The second manuscript aimed to evaluate interactions between cetaceans and artisanal fishing in a Marine Protected Area (MPA) located on the continental shelf of Paraíba, Northeast Brazil, through interviews with fishermen engaged in artisanal fishing within the Naufrágio Queimado MPA. Ethnographic tools were employed for this purpose: field diary, semi-structured questionnaires, and illustrative boards with images of dolphin species occurring on the Brazilian coast. A total of 41 interviews with fishermen from ten locations were conducted. Fishing boats (37%; n = 25) were the most commonly used type of vessel, while handlines stood out (33%; n = 36) as the most commonly used fishing gear by respondents. Accidental capture of turtles and sharks represented 26% (n = 28) of non-target animal captures. All respondents (100%; n = 41) reported sighting dolphins during artisanal fishing activities. The species most reported by fishermen were Sotalia guianensis (39%; n = 27) and Tursiops truncatus (23%; n = 16). Theft-type interaction (23%; n = 30) was the most cited by fishermen. The fishing gear variable showed a significant relationship with fishermen's perceptions of interactions, and boat size was significantly related to all interaction categories. Our data demonstrate the need for a better understanding of cetacean interactions with fishing, especially based on fishermen's perceptions of these interactions. Continuous dialogue between fishermen, researchers, and environmental agencies is necessary to understand the needs and challenges in the management, sustainable use, and conservation of species and ecosystems.