Sensitivity of the neotropical teleost <i>Odonthestes bonariensis</i> (Pisces, Atherinidae) to chromium(VI), copper(II), and cadmium(II)

Fish have been historically used to assess biological effects of xenobiotics in aquatic environments. Although most studies have been conducted using species of the Holartic Region, the assessment of the sensitivity to toxicants on Neotropical species is recent (Ronco et al. 2000). The atherinid teleost Odonthestes bonariensis is a widespread and characteristic fish species from the meridional sector of the 'del Plata' basin. It inhabits shallow ponds, rivers and estuaries with moderately hard to hard waters with variable conductivity, from fresh to brackish (Conzono and Claverie 1990; Villar and Bonetto 2000). This oviparous and planktonic fish has an important economic value due to both sport and commercial fishing (Bonetto and Castello 1985) and has been introduced in many other geographical regions from Bolivia and Chile to Japan (Welcome 1988). In spite of the extensive literature available on its biology (Lopez et al. 1991) and its phylogenetic and ecological relationship to Menidia beryllina a species widely employed in bioassays, the effect of environmental contaminants on O. bonariensis has been poorly studied (Menone et al. 2000; Carriquiriborde et al. 2000). A recent publication reports on the sensitivity to toxicants of Odonthestes regia, a marine species, from the Pacific Ocean (Silva et al. 2001). The present study reports on the sensitivity of O. bonariensis to salts of three toxic metals of environmental significance - Cr(VI), Cu(II) and Cd(II) -, in laboratory acute toxicity tests, in relation with the origin and age ofthe organisms, time of exposure and the water chemistry. Results will be useful for future risk assessment studies and planning strategies in environmental programs of the region.

Centro de Investigaciones del Medioambiente