LAUSR

Aquatic invasive species (AIS) pose significant threats to the biodiversity of freshwater ecosystems worldwide. Consequently, it is crucial to understand the distribution and growth rates of AIS to protect susceptible lakes and rivers from potential invasions. Zebra mussels (Dreissena polymorpha) originated from the Ponto-Caspian region and were first recorded in the mid-1980s in the North American Laurentian Great Lakes. In 2013, zebra mussels were first observed in four harbours on Lake Winnipeg, Manitoba, Canada. Since then, the species appears to be spreading rapidly throughout Lake Winnipeg. Here, we present the results of the distribution of zebra mussels in the south basin of Lake Winnipeg along a 7 × 7 km grid. In fall of 2016, zebra mussels were widely distributed in the south basin of Lake Winnipeg. The highest observed density of zebra mussels on artificial substrate was 16.5 individuals per cm. Mean length of zebra mussels decreased with depth and latitude. This work provides valuable information for the management of AIS prevention and monitoring programs for waterbodies with similar conditions in Central and Western Canada and the United States.