Estudo etnobiológico comparativo do conhecimento popular de pescadores em diferentes regiões do litoral brasileiro e implicações para a conservação do Boto-cinza Sotalia guianensis (van Bénéden, 1864) (Cetacea, Delphinidae)

Abstract

Based on the possible negative influence produced by conflicts betwen the traditional comunity and the boto-cinza (Sotalia guianensis) this study has as objective to describe and evaluate the state of knowlodge, practice and believes of artisanal fishermans related to boto-cinza. Further to obtain information about the ecology and describe the behavioural patterns exihibit by the species based on the informations of the fisherman and identify the relation betwen them and the boto during the fishery activities. The work was realized on the extreme south of the state of Bahia, at municipality of the Prado on the Fisherman’s Colony Z-23 and Nova Viçosa on the Fisherman’s Colony Z-29, on the state of Espirito Santo on the region of Barra do Riacho, municipality of Aracruz, on the Fisherman’s Colony Z-7; at the state of Rio de Janeiro, at Baia de Sepetiba on the Fisherman’s Colony Z-15 and on the extreme south of the state of São Paulo, on the area of the Complexo Estuarino-Lagunar of Iguape-Cananéia on the Fisherman’s Colony Z-9. The informations were colected betwen the months of september of 2005 to april of 2006. were made 100 interviews with the fishermans, 40 on the extreme south of Bahia, 20 on the north coastland of the state of Espirito Santo, 20 on the south portion of the state of Rio de Janeiro, and 20 on the south of the state of São Paulo. The informations was colecteds through structured interviews, basead in one pattern-questionnaire previously elaborated, were made recorder of evidence used a oriented logbook for the same. Were selected 77 informer that clearly identificated S. guianensis through of characteristics defined by fishermans considering: color (back’s gray, white belly, browny or pinky), length of the body (adult of 1 – 2,5m), geral behaviour (in the presence of boat and bather – evasive behaviour), locality of occurrence of animals (beach, river, estuary and sea near coastland). After this selection, were analysed the data related to fishermans such as participation in education of environment, time of fishing on the local, local of fishing (sea, river, xxi estuary), artifact or fishing`s arts, boats, autonomy in the sea (embarkation`s days). All this informations were related to identification of boto-cinza. Examined to the datas related with the interference of boto in the activities of fishing, collision betwen boats and botos, pattern behavioural of the specie, behaviour of the animal in the presence of boats, size of group, diet, area of occurrence and sighting, seazonality, behaviour of nestling, incidental capture of boto in the artifacts of fishing, the types of artifacts used for the fishermans, area where occur the incidental captures, destine gave to carcass, local of fishing and fish caught of value economic. To the analyses were made the statisticals tests of Kruskal–Wallis and the test of Mann-Whitney, used the program statistical BioEstat (2.0). The results showed that the artisanal fishing activits permit easy identification of boto by fishermans that practice this type of fishing the majority of informers demonstrated knowledge the boto through characteristcs like color, lenght of the body and location of the occurrence of the animals. Was possible to identify a regard perception of the fishermans about the habitat, behaviour and diet of the boto-cinza, beyond of identificated the seazonal, behaviourals patterns and possible preys presents in the diet of the boto. There are positives interactions related to the fact of the animals aid the fishermans during the fishing and also negatives interactions where the animals scare the fishes and with this the fishermans can’t fishing they. The informers can distinguish juveniles individuals of adult through color, lenght of body and observation of the behaviourals patterns. Can observe the occurrence of the incidental capture of the boto, caused by nets of wait used on the fishing. This captures are more frequents on the area of the ‘open sea’, occurring also on the bar, beach, estuary, coast and bay. The carcass that are found can be eaten; used like bait in the fishing of the shark and too be discardeds. In spite of occur the capture there isn’t apparent conflicts on the vision of the fishermans betwen their activity and the boto. This results intend to contribute to the conservation of the boto-cinza on the specifics areas, together with the participation of the local population, subsidizing others works and proposals of the management to the diminuition of the impacts about the populations of the species.