Early post-hatching sensitivity of a Neotropical annual killifish to glyphosate-based-herbicide

Abstract

Neotropical annual killifish are short-lived fish species which inhabit exclusively temporary freshwater wetlands. These organisms are proposed as standard fish models, but are poorly studied for pollutants and pesticide effects, including herbicides based on glyphosate that are widely used worldwide. Effects of different Roundup® concentrations (1.5–6 mg/L), a commercial formulation containing glyphosate, are assessed on the early post-hatch survival of the annual killifish species Garcialebias botocudo and compared to the sensitivity (LC50 to 24, 48, and 72 h) of juveniles of other freshwater fish species (annual and non-annual). Early post-hatched individuals (48 h age) of G. botocudo showed sensitivity to Roundup®, reaching 55% mortality after 72 h of exposure to 6 mg/L of glyphosate and an LC50 of 6.5 ± 1.6 mg/L. The sensitivity of our biological model was generally higher compared to other non-annual fish species used as models in ecotoxicological studies, showing to be an excellent bioindicator for this xenobiotic. The habitat and characteristics of annual killifish which inhabit temporary wetlands, make them more threatened by pesticides. This situation becomes even more worrying in Brazil, as there is a scenario of increase and uncontrolled use of pesticides, especially those based on glyphosate, in the coming years.