Avoidance behavior of cold-, cool-, and warmwater fish exposed to Zequanox in a two-choice preference chamber, data release

Zequanox® is an EPA-registered biopesticide for controlling populations of dreissenid mussels (zebra and quagga mussels). Zequanox has demonstrated selective toxicity toward dreissenid mussels; however, a recent laboratory study indicated the potential for Zequanox to impact a non-target salmonid species. We assessed the potential exposure risk by observing the avoidance behavior of two representative species of cold-, cool-, and warm-water fish (lake trout, brook trout, lake sturgeon, yellow perch, fathead minnow, and bluegill). Fish were subjected to the maximum allowable concentration of Zequanox per the product label (100 mg/L active ingredient). Naïve juvenile fish (n = 30 per species) were individually observed in a two-current choice tank with simultaneous and unobstructed flow of treated and untreated water. Each individual fish was observed during a control period (20 min) with no treatment and two treatment periods (20 min each), where the treated side was alternated between treatment periods. Positional data was collected and tabulated in real time with EthoVision® XT software. Zequanox concentrations and water quality (pH, dissolved oxygen, temperature, and specific conductance) were monitored during each trial. Results from this research will help inform resource managers of the likelihood of non-target fish to avoid Zequanox treated areas, thereby assisting in the establishment of treatment-related risk assessments.