Here we present the weight-length relationship of the spinner shark (Carcharhinus brevipinna) on the continental shelf of southern Brazil, estimated from an analysis of 125 specimens. No significant differences between males and females, so the data were grouped in equation W = 0,003L 3.1534 . The results presented here are the first to approach sharks above 75 cm and confirm the positive allometric growth of the species. RESUMOAqui apresentamos, a relação peso-comprimento do tubarão-rotador (Carcharhinus brevipinna) na plataforma continental do sul do Brasil, estimada a partir de análise de 125 exemplares. Não houve diferenças significativas entre machos e fêmeas, portanto os dados foram agrupados na equação W = 0,003L 3.1534 . Os resultados aqui apresentados são os primeiros a abordarem tubarões acima de 75 cm e confirmam o crescimento alométrico positivo da espécie.

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The present study compares the trophic ecology of two guitarfishes (Pseudobatos percellens and Pseudobatos horkelii) from the continental shelf of the São Paulo State, Brazil, caught by the bottom pair trawls between 2007 and 2009. These two sympatric species are under different threat categories, “Vulnerable” and “Critically Endangered,” respectively, according to Brazilian agencies. Thus, any study considering trophic ecology parameters is pivotal in understanding the trophic ecology role of such species in the ecosystem. The authors analysed 500 stomachs of P. percellens and 108 of P. horkelii, quantifying with dietary indexes: numerical (%N), gravimetric (%W), frequency of occurrence (%FO) and the prey‐specific index of relative importance (%PSIRI). For P. percellens and P. horkelii, 26 and 14 different prey items were found, respectively. Crustacea and Teleostei were the most important prey items for both species, indicating a specialist feeding behaviour due to their low niche amplitude. The results provide evidence related to ontogenetic dietary shift in P. percellens and individual‐level diet specialization in both species. These two benthic‐demersal elasmobranchs are important mesopredators (3,7 for P. percellens, and 3,5 for P. horkelii) in the study area, with high trophic‐level values.