Ecologia trófica da comunidade de peixes do reservatório do Lobo (Broa), Brotas-Itirapina/SP, com ênfase à introdução recente da espécie alóctone Cichla kelberi (Perciformes, Cichlidae)
Abstract
The introduction of predatory species has carrying deep modifications on the original
fish wildlife structure at aquatic environments. The feeding spectrum characterization
of fish community from Lobo Reservoir (Broa), beside providing information about the
species biology and establishing trophic guilds, made possible the follow-up of trophic
alterations due the dam constructions and species introduction, beyond to propose ways
of mitigation or management in order to sustain the environment fishery production.
The Alimentary Index was used to see the features of the species feeding habits, and to
verify if competition exists among the species, was used the Overlap and Similarity
Index among the diets. A total of 23 species were collected and distributed in five
trophic guilds. Three species present omnivorous diet, six species had shown
insectivorous diet and present the major number of individuals, and the piscivorousinsetivorous
guild presented two species. The piscivorous are represented by Hoplias
malabaricus and Cichla kelberi. Cyphocarax modestus is real iliophagus, but his diet is
quite similar to the Hypostomus ancistroides, detritivorous, and to the omnivorousdetritivorous
Geophagus brasiliensis, Oreochromis niloticus and Phalloceros
caudimaculatus. Poecilia reticulata presented a detritivorous diet, but with large
participation of insects, and the diet of Serrapinnus heterodon is described as
phytoplancktophagus. In the general community analisys was observed that peacook
bass do not present overlap related to any specie, but his ascendancy on the community
is shown through the restriction on the distribution of P. caudimaculatus and Corydoras
aeneus and abstence of Hyphessobrycon bifasciatus and Cetopsorhamdia iheringi. It
was observed yet a decrease of relative occurrence of G. brasiliensis e H. malabaricus
and an increase of C. kelberi and Astyanax altiparanae, related to previous researches.
Therefore, we are dealing with an environment disturbed by the establishing of peacook
bass, despite his recently introduction, being indispensable the follow-up and
management in order to dimishing the impacts already showed