The Spiny Water Flea in Québec’s Waterways

The Spiny Water Flea in Québec’s Waterways

The spiny water flea, Bythotrephes longimanus, is a small zooplankton crustacean native to Central Europe and the Caspian Sea basin. This aquatic invader measures between 1 and 1.5 cm, with its barbed tail making up more than half of its total length.

It was first detected in Québec in 2015 in the Haut-Richelieu area, and its presence has since expanded into several regions, including Abitibi–Témiscamingue and the Outaouais. More recently, the species was also found in the Baskatong reservoir, marking a significant spread toward inland water bodies. It has also been observed in the Ottawa River, particularly near Lake McConnell.