Answer:
Sea Lampreys
Step-by-step explanation:
Niagara Falls acted as a natural barrier preventing sea Lamprey movement to Lakes Erie, Huron, Michigan, and Superior. However, when the Welland Canal (constructed to bypass the falls) was deepened in 1919, sea lampreys gained access to the rest of the Great Lakes. By 1938, they had invaded all of the Great Lakes.May 4, 2018