Feeding of guitarfish Rhinobatos percellens (Walbaum, 1972) (Elasmobranchii, Rhinobatidae), the target of artisanal fishery in Southern Brazil

Abstract

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.

Diet of the chola guitarfish, Rhinobatos percellens (Rhinobatidae), in the Paranaguá Estuarine complex

“…In general, decapod crustaceans tended to be the most important prey of rhinobatid species (e.g. Talent 1982, Kyne and Bennett 2002, White et al 2004, Bornatowski et al 2010, 2014b. The importance of Polychaeta and Amphipoda was reduced in R. percellens feeding, which agreed with the results obtained on the continental shelf for the same species (Bornatowski et al 2010(Bornatowski et al , 2014b.…”

“…According to Espinoza et al (2011), the patterns of site fidelity and inter-annual use remain uncertain for many coastal elasmobranchs due to the lack of quantitative behavioral data. The specimens of R. percellens caught in the estuary were smaller (< 73.0 cm -TL) than the specimens obtained by Bornatowski et al (2010), who used gillnets on the continental shelf in Southern Brazil (between the coasts of Paraná and Santa Catarina). The difference in length could be related to the fishing method, associated with environment characteristics (estuary x continental shelf).…”

“…Talent 1982, Kyne and Bennett 2002, White et al 2004, Bornatowski et al 2010, 2014b. The importance of Polychaeta and Amphipoda was reduced in R. percellens feeding, which agreed with the results obtained on the continental shelf for the same species (Bornatowski et al 2010(Bornatowski et al , 2014b. Other food items, such as the squid Lolliguncula brevis (Blainville, 1823), was one of the food items of R. percellens on the continental shelf of Southern Brazil (Bornatowski et al 2010(Bornatowski et al , 2014b, but it did not appear on this study in estuarine waters.…”

“…Shibuya et al 2005, Bornatowski et al 2010, Grijalba-Bendeck et al 2012. The lack of studies of R. percellens in estuaries and the lack of data about feeding biology of elasmobranchs in these environments in Brazil are factors that triggered this work, which showed that R. percellens use the estuary for feeding purpose.…”

“…Studies show that the species has been overexploited by fisheries, particularly on the Brazilian continental shelf (De-Franco et al 2010). Meneses et al (2005) report that R. percellens has no commercial value in some states of northeastern Brazil, while Costa and Chaves (2006) and Bornatowski et al (2010) report commercialization in the south. Based on preliminary investigations in the Paranaguá Estuarine Complex (a subtropical estuary in southern Brazil), R. percellens of several size classes can be found throughout the year (E.C.…”