EarthTec QZ can effectively suppress zebra mussels according to independent study

EarthTec QZ can effectively suppress zebra mussel veligers, juveniles, and adults according to a joint study by the United States Geological Survey (USGS) and the University of Minnesota Aquatic Invasive Species Research Center (MAIRSC). The study was conducted on two bays in Lake Minnetonka, Minnesota during the summer of 2019. It is the largest-scale project of its kind to date.

Zebra mussels were first discovered in Lake Minnetonka in 2010 and have established themselves throughout the lake since then. The goal of the study was to determine whether low doses of ionic copper over a long duration would effectively suppress zebra mussels, especially the microscopic juveniles called veligers. The project is part of a broader effort to develop strategies for suppressing zebra mussels that have minimal impact on water quality and non-target species.

Considerable effort went into testing the impact of the treatment on target species, non-target species and water quality. The design of the project included a treated test site, St. Alban’s Bay, and an untreated control site, Robinson’s Bay. The two sites are very similar in water quality and zebra mussel density, with some variations in size, depth and substrate.

Preliminary results were presented in a webinar hosted by the University of Minnesota AIS Detectors program on August 26, 2020. The results show that EarthTec QZ greatly suppressed zebra mussel veliger density (i.e., by > 90%) as measured 1 day and 14 days post-treatment, juvenile zebra mussel settlement as measured 30- and 90-days post-treatment, and live adult zebra mussel density as measured in SCUBA surveys two months post-treatment.