AUGUST 2020
The zebra mussel is a small freshwater mussel that is native to the Caspian and Black Seas. These mussels have spread to North America, as passengers in the ballast water of transatlantic ships, and are found in waterbodies throughout the eastern portions of Canada and the United States. Zebra mussels have recently been found in southern Manitoba in several areas of Lake Winnipeg and the Red River. High reproductive rates and the absence of native predators often result in large population increases in freshwater lakes.
The larval stage of the mussel is a microscopic veliger that floats freely with water currents, expanding its range. When the veliger matures, it settles and attaches to hard, submerged surfaces such as rocks, the hulls of boats, generating stations and other important infrastructure. Of increasing concern is the possibility that zebra mussel veligers may be transferred between dis-connected water bodies by human activities.
Manitoba Hydro contracted AAE Tech Services Inc. to carry out a monitoring program to detect zebra mussel invasions at the early stages of colonization in major water bodies in Manitoba. Veliger sampling was conducted in Au-gust and September of 2019 in several major waterbodies in Manitoba including the Assiniboine, Winnipeg and Nelson Rivers as well as at Cedar Lake near Grand Rapids.
As part of this project, AAE provided the following:
• Vertical tows in deep calm waters using plankton net;
• Horizontal tows in shallow water using plankton net;
• Oblique tows in heavy current using plankton net;
• Water quality measurements at all sampling sites;
• Laboratory analysis by ALS Environmental for zebra mussel veliger presence and enumeration;
• Detailed reporting on the progression of zebra mussel invasion front during the study period;
• Recommendations for mitigation and further action.
AAE followed the Aquatic Invasive Species Regulations and disinfected the boat, trailer and all equipment that came into contact with water using an Easy-Kleen Hot Water Pressure Washer before moving to the next water body.
