A B S T R A C TRhinobatos percellens is one of three species of Rhinobatidae found on Brazilian shores and is one of the most abundant species on the shallow continental shelf of Paraná and Santa Catarina States. Specimens caught by artisanal fishery between July/2001 and March/2003 by fishing communities located on the frontier between two southern Brazilian States (Paraná and Santa Catarina) had their stomach contents analyzed. According to the Alimentary Index (IAi), Decapoda (69%) and Teleostei (22%) were the main items consumed. Polychaeta, a common prey consumed by several benthonic fishes, was poorly represented in the feeding of R. percellens. This fact may be related to the availability of prey in the environment, or to the size of the guitarfish analyzed (ontogeny). Seasonal variance of main preys (with higher IAi) was observed: Dendrobranchiata and Pleocyemata displayed higher percentages in spring and autumn, Teleostei in the winter and Brachyura during the summer. R E S U M ORhinobatos percellens é uma das três espécies de Rhinobatidae encontrada na costa brasileira e uma das espécies de elasmobrânquio mais abundante na plataforma continental dos estados do Paraná e Santa Catarina. Indivíduos capturados pela pesca artesanal entre Julho/2001 e Março/2003 nas comunidades pesqueiras localizadas entre o Paraná e Santa Catarina tiveram seus conteúdos estomacais analisados. O Índice de Importância Alimentar (IAi) mostrou que as principais presas consumidas foram Decapoda (69%) e Teleostei (22%). Polychaeta, principal presa ingerida por várias espécies de peixes bentônicos foi pouco expressiva na alimentação de R. percellens. Essa diferença pode estar relacionada com a disponibilidade de presas no ambiente ou com o tamanho das raias analisadas (ontogenia). De acordo com análises sazonais, observou-se que os camarões Dendrobranchiata e Pleocyemata foram as principais presas consumidas durante a primavera e outono, Teleostei durante o inverno e Brachyura durante o verão.
Apresentam-se atributos de estrutura populacional, reprodução e alimentação de Paralonchurus brasiliensis no litoral Sul do Estado do Paraná. As coletas foram realizadas com rede de arrasto de fundo, de março de 1999 a janeiro de 2000, sobre as isóbatas 10 e 15 m. Os indivíduos são mais abundantes durante a primavera, época de recrutamento dos jovens menores que 93 mm. A relação peso/comprimento para sexos grupados é PT(g) = 2,74E-6.CT(mm)3,22 (n = 659; R² = 0,99). Maturação gonadal é registrada a partir da classe de comprimento 130-165 mm, e o comprimento médio de primeira maturação - sexos grupados - é estimado em 175 mm. Poliquetas são o item alimentar mais freqüente em todas as classes de tamanho e estações do ano, seguidos de crustáceos e peixes. Conclui-se que o período reprodutivo da espécie estende-se do outono (início da maturação) ao verão (final da desova). Após a primavera, os jovens provavelmente saem da área de profundidade 10 m. A interdição do arrasto camaroneiro nesta profundidade durante primavera e verão seria eficiente para reduzir o by-catch de P. brasiliensis, hoje composto por indivíduos recrutas ou em proximidade de desova.
Lead concentrations and isotopic composition have been measured in bone and teeth of small cetaceans belonging to three species (Delphinus delphis, Phocoena phocoena and Stenella coeruleoalba), to evaluate the toxicological risk and to determine sources of lead in the European waters. Lead concentrations, far lower than threshold value inducing toxic effects in human, were higher in teeth than in bones, but highly correlated between the two tissues (r=0.92, p<0.001). Large variations of 206Pb/207Pb values in bone tissue showed that cetaceans must be submitted to various atmospheric influences. No geographical differences appeared which is consistent with studies on their distribution indicating seasonal movements between Brittany waters and the Bay of Biscay. The negative correlation between 206Pb/207Pb ratios and age of the individuals reflected the decrease in the production of alkyl lead in Europe, i.e., the increasing use of unleaded gasoline.
The present study was conducted in two artisan fishing communities in the cities Guaratuba (Paraná) and Itapoá (Santa Catarina), in the South Brazilian coast. Stomach contents of Sphyrna zygaena specimens were identified, showing three categories of food items. The most important feeding categories were teleosts (78.6%) and cephalopods (60.7%), represented by the sardine Harengula clupeola the squid Loligo sp., both considered the main food items of S. zygaena in the studied region. O presente estudo foi conduzido em duas comunidades da pesca artesanal nas cidades Guaratuba (Paraná) e Itapoá (Santa Catarina), no sul da costa brasileira. Os conteúdos estomacais de indivíduos Sphyrna zygaena foram identificados, sendo os itens alimentares agrupados em três categorias. As categorias mais importantes foram teleósteos (78,6%) e cefalópodes (60,7%), representados pela sardinha Harengula clupeola e a lula Loligo sp., ambos considerados como principais itens alimentares de S. zygaena na região estudada.Palavras-chave: Elasmobranchii, alimentação, pesca artesanal, costa paranaense.
BrazilTechnical, biological and socioeconomic factors act as obstacles in the development of fishing activity in the Guaratuba Bay, southern Brazil. Amongst the difficulties registered, the following stand out: there was little variety of fishing gear; the purchasing power of the fishermen was low; there was a lack of regularity in the presence of the target species in the estuary; legislation restricted the use of certain gear at particular times; the size of the individual fish was small when compared to those from the continental shelf. Aquaculture could offer an alternative to the revenue of the fishermen, but cultural tradition and the lack of financial resources make it difficult to introduce aquaculture as an activity for the fishermen. The pessimism encountered in the community indicates that the future of artisanal fishing in this estuary is uncertain.
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