Selectivity of gillnets for a non-native fish species in a neotropical reservoir, Parana, State, Brazil

Abstract

Biological invasions are considered the second main cause of loss biodiversity in aquatic environments. Thus, many techniques have been developed with the aim of eradicating undesirable species. Then, this paper had the purpose of estimate the selectivity of the gillnets used to catch Odontesthes bonariensis, introduced specie in Salto Santiago reservoir, Iguassu River, Brazil. Samples were made bimonthly from July 2003 to March 2013. Altogether 6,952 individuals were captured. The mesh sizes of 2.5 cm and 3.0 cm are the most effectively both captured 89.90% of the individuals. The optimal sizes of capture estimates for mesh sizes of 2.5 and 3.0 cm were 13.35 cm and 16.00 cm, respectively. Thus, we suggest the intense use of gillnets with mesh sizes less than 3.0 cm, to capture small sized individuals at first maturation.