The effect of artificial increases in water conductivity on the efficiency of electric fishing in tropical streams (Paraná, Brazil)

Abstract

Four sites in three small tropical streams each were sampled with three successive electrofishings per constant unit effort, starting at the site with lowest natural water conductivity. Each second-fourth site was sampled at double water conductivity (up to 300 µS cm-1 only) by dissolving salt in the water. Electric fishing efficiency estimated by three efficiency indexes was not significantly correlated with increasing conductivity. The reasons for this result are discussed.