Gyrinus affinis was recorded from New Brunswick by Oygur and Wolfe (1991), Nova Scotia by Oygur and Wolfe (1991) and Roughley (1991), and Prince Edward Island by Majka (2008). It is one of the most abundant and widely distributed species in the region (Fig. 8). Oygur and Wolfe (1991) recorded the species from streams and lakes while Morrissette (1979) reported it from stagnant water. It is found in both lotic (41%) and lentic (59%) habitats ( Oygur and Wolfe 1991).