Assessing the potential movement of invasive fishes through the Welland Canal

Aquatic invasive species have become one of the most serious threats to freshwater biodiversity due to the severe negative impacts they can have on native ecosystems. Examining the potential pathways that aquatic invasive species may use to invade and spread throughout the Great Lakes basin is a critical step in preventing their spread. This study focused on a major shipping canal, the Welland Canal, as a possible dispersal corridor for invasive species within the Great Lakes basin, specifically evaluating the ability of fishes to utilize canals and locks as a dispersal corridor between waterbodies. To determine the extent to which fishes were moving within the canal and through the eight locks, we captured, tagged, and released 179 fish of 10 species within the canal with acoustic tags and tracked their movement using 34 acoustic receivers placed in strategic locations within the system. Seven tagged fish (3.9%) moved from the canal into lakes Ontario or Erie. Within the canal, only one fish (0.6%) moved through the flight locks (locks 4, 5, and 6). These results indicate that fishes can move through the Welland Canal and out of it into lakes Ontario or Erie, but that the locks, particularly the flight locks, limit such dispersal.