Feeding ecology of elasmobranch species in southeastern Brazil

Alessandra F. Viana,Jean L. Valentin,Marcelo Vianna

doi:10.1590/1982-0224-20160176

Alessandra F. Viana, Jean L. Valentin + Show 1 more

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https://doi.org/10.1590/1982-0224-20160176

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Abstract

ABSTRACT The feeding ecology of five elasmobranch species was studied on the southern coast of Rio de Janeiro, southwestern Atlantic Ocean. The specimens were caught with a trawl or bottom longline between January 2006 and August 2007. The diets of Psammobatis rutrum and Psammobatis extenta appeared to be basically carcino-benthophagous, with a very small niche width. Rioraja agassizii was basically carcino/ichthyo-benthophagous, also with a narrow niche, including teleost fish and shrimp, but in different proportions according to age and sex. Rhizoprionodon lalandii was ichthyophagous, not influenced by age or sex. The analyses of these species and Atlantoraja cyclophora indicated two trophic groups: one composed of the smaller rays, P. extenta and P. rutrum, which basically fed on small crustaceans, polychaetes and nematodes; and the other of R. lalandii and the larger rays R. agassizii and A. cyclophora, which preyed on teleost fish and brachyurans.

Highlights

Studies on the feeding of organisms in the natural environment are important mainly to extend knowledge of their trophic ecology, including resource sharing and competition, for the understanding, administration and management of ecosystems (Valls et al, 2011; Braga et al, 2012; Estalles et al, 2015)
The goal of this study was to generate information about the diets of Psammobatis rutrum, Psammobatis extenta (UERJ 2125), Rioraja agassizi (UERJ 2147) and Rhizoprionodon lalandii (UERJ 2168) in southeastern Brazil, by identifying the main food items of the species; determine differences in their diets according to the sex and stage of maturity; and investigate the diet overlap of these four species, as well as of Atlantoraja cyclophora (UERJ 1256) (Viana, Vianna, 2014)
We seek to contribute with this study on the feeding ecology of four species of rays and one shark

Summary

Introduction

Studies on the feeding of organisms in the natural environment are important mainly to extend knowledge of their trophic ecology, including resource sharing and competition, for the understanding, administration and management of ecosystems (Valls et al, 2011; Braga et al, 2012; Estalles et al, 2015). These studies contribute to explaining the variations in growth, reproduction, migration and predation behavior. The price per kilogram of shark fins is about $1,697 and the price per individual for marine species ranges from $11,121 for dwarf sawfish to $341,139 for the whale shark (McClenachan et al, 2016)

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