Alewife - in The North American Great Lakes

In The North American Great Lakes

Alewives are perhaps best known for their invasion of the Great Lakes by using the Welland Canal to bypass Niagara Falls. Alewives colonized the Great Lakes and became abundant mostly in Lake Huron and Lake Michigan. They reached their peak abundance by the 1950s and 1980s. Alewives grew in number unchecked because of the lack of a top predator in the lakes (lake trout were essentially wiped out around the same time by overfishing and the invasion of the sea lamprey). For a time, alewives, which often exhibit seasonal die-offs, washed up in windrows on the shorelines of the Great Lakes. Their control was the impetus for the introduction of various Pacific salmon species (first coho, and later the Chinook salmon) to act as predators on them. This caused the development of a salmon/alewife fish community, popular with many sport anglers. Alewives, however, have been implicated in the decline of many native Great Lakes species through competition and predation.