Impactos de pisciculturas em tanques-rede sobre a ictiofauna da ...

Abstract
Impactos de pisciculturas em tanques-rede sobre a ictiofauna da represa de Chavantes:
alimentação, parasitas e bromatologia - Autor: Igor Paiva Ramos
Currently, the deployment of fish farming in cages in Brazilian reservoirs is a source of
negative impacts on water quality and biota. This activity acts as a secondary source of energy
to the aquatic ecosystem, such as ration wastes that attract adjacent biota, causing changes in
the structure of local community. The aim of this study was to evaluate the influence of fish
farming in cages on fish species attracted to these areas, focusing on biological features (diet,
bromatology and parasitology) in a large dam in the middle Paranapanema River. To this aim,
it was used five fish species (Astyanax altiparanae, Galeocharax knerii, Iheringichthys
labrosus, Pimelodus maculatus and Plagioscion squamosissimus). The specimens were
captured with gill nets in areas around the cages (CF) and in areas without the influence of
this type of activity (CT). It was characterized the diet for the five selected species,
bromatological composition of the species G. knerii and P. maculatus, and the infection rate
of metacercariae of Austrodiplostomum compactum in P. squamosissimus was assessed, being
all comparative analysis between the CF and CT areas. The results show that there were
significant changes in the diet of trophic generalist species (A. altiparanae, P. maculatus and
I. labrosus) with consequent increase in condition factor values in the TR areas. Trophic
specialist species, such as the carnivorous fish G. knerii and P. squamosissimus, showed small
differences between CF and CT areas regarding diet, with no significant changes for other
analyses performed. Concerning bromatological analysis, significantly higher values were
observed (p 0.05) for P.
maculatus. There were no differences (p> 0.05) between G. knerii specimens captured in the
tank and control areas. Regarding parasitological aspects of P. squamosissimus, the mean
intensity of infection (CF = 20.31 ± 1.13 / CT = 4.29 ± 7.14), prevalence (CF = 86.4% / CT =
57.1%) and average abundance (CF = 17.70 ± 6.27 / CT = 2.35 ± 0.77) showed significantly
higher values in the tank area comparing to control area (p