Fishing activity in Northern Rio de Janeiro State (Brazil) and its relation with small cetaceans

Abstract

Research on fishing activity at Atafona village, in Northern Rio de Janeiro, Brazil (21°35'S), was carried out between 1987-96 for the purpose of relating it to the accidental capture of small cetaceans and of estimating the relationship between fishing activity and the diet of small cetaceans. Data on fishing operations were obtained at the cold storage plants management, from interviews with fishermen and personal observations. The most representative fishing resources were Xyphopenaeus kroyeri, Micropogonias furnieri, Carcharhinus plumbeus, C. acronotus,and Rhizoprionodon porosus. Gillnets are responsible for the accidental capture of small cetaceans in the region, mainly Pontoporia blainvillei and Sotalia fluviatilis (marine form). Four types of gillnets that are used on the region ("minjuada", "sarda", "caçoá" and "pescadinha") were dangerous to these species because they are placed in their preferred habitat. There is no competition between fishermen and small cetaceans due to the selection in the capture of commercialized fishes<br>Investigação sobre a atividade pesqueira na localidade de Atafona, Norte do Rio de Janeiro, Brasil (21º25`S), foi conduzida entre 1987-96 com o objetivo de relacioná-la com a captura acidental e a dieta dos pequenos cetáceos. Dados sobre as operações pesqueiras foram obtidos na administração dos entrepostos de pesca, através de entrevistas com pescadores e observações pessoais. Os recursos pesqueiros mais representativos foram Xyphopenaeus kroyeri, Micropogonias furnieri, Carcharhinus plumbeus, C. acronotus, and Rhizoprionodon porosus. As redes de espera são responsáveis pela captura acidental de pequenos cetáceos na região, principalmente de Pontoporia blainvillei e Sotalia fluviatilis (forma marinha). Quatro tipos de redes de espera que são usadas na região ("minjuada", "sarda", "caçoá" and "pescadinha") foram mais perigosas para essas espécies pois são colocadas no seu hábitat preferencial. Não existe competição entre pescadores e pequenos cetáceos devido à seleção na captura dos peixes comercializados

Hábito alimentar do peixe-espada adulto, Trichiurus lepturus, na costa norte do Rio de Janeiro, sudeste do Brasil

“…No sul do Brasil, Martins et al (2005) relatam que o canibalismo é importante principalmente para os indivíduos adultos, podendo ocorrer devido a elevada abundância de presas co-específicas, comportamento gregário da espécie durante a alimentação e diminuição da produtividade biológica no ecossistema marinho daquela região nos meses de verão e outono. No norte do Rio de Janeiro, a escassez de presas parece não ser o fator que esteja conduzindo a espécie ao canibalismo (Di Beneditto et al, 1998;Di Beneditto, 2000;Di Beneditto et al, 2001) devido a alta produtividade biológica associada à desembocadura do Rio Paraíba do Sul. No entanto, os demais fatores não podem ser desconsiderados como explicativos para tal comportamento na região.…”

Incidental mortality of franciscana (<i>Pontoporia blainvillei</i>) in the artisanal fishery of Praia Grande, São Paulo State, Brazil

“…While fishery monitoring and bycatch estimates have been obtained for other areas (e.g. FMA I [Di Beneditto et al, 1998]; FMA III [Moreno et al, 1997;Praderi, 1997;Secchi et al, 1997;Kinas and Secchi, 1998] and FMA IV [Corcuera, 1994;Corcuera et al, 1994;Cappozzo et al, 2000]), information for FMA II is scarce and limited to small geographic areas (e.g. Zanelatto, 1997;Rosas, 2000).…”

“…The species has been extensively captured in coastal gillnets throughout its range (e.g. Perez-Macri and Crespo, 1989;Praderi et al, 1989;Corcuera, 1994;Pinedo, 1994;Secchi et al, 1997;Di Beneditto et al, 1998). Given its coastal distribution, within 30m of depth, the franciscana is vulnerable to most gillnet fisheries operating close to shore (e.g.…”

Dolphins, whales and porpoises : 2002-2010 conservation action plan for the world's cetaceans

“…Although the franciscana is the species of greatest concern Di Beneditto et al 1998;Kinas and Secchi 1998;Ott 1998;Secchi 1999), the tucuxi has also experienced relatively high levels of incidental mortality in some areas (Siciliano 1994;Zanelatto 1997;Alves-Júnior et al 1996;Beltrán-Pedreros and da Silva 1998;Di Beneditto et al 1998;Santos 1999). Other species, including bottlenose, spinner, Risso's, roughtoothed, Atlantic spotted, and common dolphins and false killer, killer, pilot, minke, humpback, and southern right whales, have been taken in lower numbers (Simões-Lopes and Ximenez 1993;Pinedo 1994;Siciliano 1994;Bassoi et al 1996;Lodi et al 1996;Di Beneditto et al 1998;Marques et al 1998;Dalla Rosa 1998;Greig et al 2001). Monitoring by on-board observers has been maintained on a regular basis in some regions (e.g., Rio Grande, Imbé/Tramandaí, and Torres in southern Brazil), but information is still almost entirely lacking on the scale and species composition of the bycatches, fishery characteristics, and fleet dynamics for most of the Brazilian coast.…”

“…The species faces various threats from human activities along its range, including incidental mortality in fisheries (Simões-Lopes and Ximenez 1993;Zanelatto 1997;Di Beneditto et al 1998;Lailson-Brito et al 1999;Monteiro-Neto et al 2000;Edwards and Schnell 2001), habitat loss and disturbance (Flores 1995;Santos 1998), and chemical pollution (Brito et al 1994). The species seems to occur as a series of small "resident" populations along the Brazilian coast (e.g., Flores 1999;Pizzorno 1999;Santos 1999), although further studies are needed to confirm it.…”