Sensitivity of invasive alien fish in Serbia black bullhead Ameiurus melas (Rafinesque, 1820) as a bioindicator of genotoxicity

Abstract

Invasive alien fish species represent one of the greatest threats to the biodiversity and ecological status of freshwater ecosystems. Within their management, their application as bioindicators of pollution in monitoring programs should be considered. The aim of this study was to examine the use of black bullhead Ameiurus melas (Rafinesque, 1820), invasive alien fish in Serbia, as a bioindicator of water genotoxicity by alkaline comet assay. Sampling was performed from June to September 2021 on Markovačko Lake, which is exposed to diffuse pollution from the application of pesticides on the surrounding agricultural land. Monitoring also included the assessment of water quality by basic physical and chemical parameters, as well as microbiological indicators of faecal pollution. Alkaline comet assay was performed on fish erythrocytes, on ten specimens per month. The study also included ten control fish from the recirculating aquaculture system (RAS), which were transferred from Markovačko Lake for breeding, and treatment of their erythrocytes with H2O2 as a positive control. Scoring of comets was performed by CometScore 2.0 software. The lowest level of DNA damage was recorded in the control group and the highest in the positive control group. August was the month with the lowest level of DNA damage, and September with the highest. Statistically significant differences were found between all groups indicating a high sensitivity of the alkaline comet assay to discriminate fine differences in the genotoxic potential of water. Knowing that black bullhead is highly abundant in stagnant waters and relatively easy to sample, this study draws additional attention to its use as a bioindicator of genotoxicity.