Fish-food interaction network around cage fish farming in a neotropical reservoir

Abstract: Aim Investigating whether wild fish accept residual ration from cage farming to the point of changing their diet and fish-food interaction network. Methods The species, Astyanax lacustris, Iheringichthys labrosus, Leporinus amblyrhynchus, Schizodon nasutus Steindachnerina insculpta, bred in Chavantes Reservoir, Upper Paraná basin, was evaluated. Samples were collected on a monthly basis - March 2008 February 2009 around (NC) reference site (RS) free influence activity. Results analyzed through graphs metrics complex network analysis, Permutational analysis variance. total number 641 individuals belonging all five species collected, 292 NC 349 RS. amount food items consumed by them comprised 24 22 has shown nested pattern two evaluated areas, which evidenced generalist structure this interaction. Connectance values mean degree networks low. Detritus most representative item both sampling sites. Three (A. S. I. labrosus) had diet. Residual fourth NC. It also for A. lacustris nasutus. Conclusions have that activity can trophic interactions aquatic systems, as well ability nasutus, L. labrosus take advantage new environment.