Reproductive impairment of a viviparous fish species inhabiting a freshwater system with anthropogenic impact

Abstract

The potential threat to animal reproduction by contaminated freshwater systems posed the necessity to identify and develop bioindicators and biomarkers to be used for screening and evaluation of the effects in organisms. The main goal of this work was to determine whether in a freshwater system pollution by sewage, agricultural, and industrial activities could cause alterations at organ?s level. We also propose the live-bearing fish, Jenynsia multidentata, as a species suitable to study the effects of contaminated aquatic environments. We compared males sampled at two different stations in Suquía River basin (Córdoba, Argentina) differing in pollution degree. The water quality based on physicochemical characteristics of the studied stations varied markedly, with a decrease in water quality at the downstream site (Station 2). At the highest polluted area it was evident the detrimental effects on liver and testis revealed through histological analysis. Male individuals from Station 2 also presented noticeable structural changes of the anal fin such as a straight gonopodium and abnormal tip area. The present results demonstrate that a freshwater system polluted by anthropogenic activities impacts on J. multidentata. The alterations registered in individuals from the polluted station indicate an impairment of male reproductive performance and imply a risk for other live-bearing species as well as the entire biodiversity. We consider J. multidentata a sentinel species, useful to evaluate the potential risk present in the studied basin, not only to itself, but to other species as well.