How the Alewife and West Coast Salmon Transformed the Great Lakes

The St Lawrence Seaway opened the Great Lakes to ocean going vessels. Since then 160 species have invaded the Lakes ecosystem, with ship ballast water being the primary suspected pathway causing drastic economic and ecological changes to the lakes.

It is thought that improvements to the Welland Canal in 1919 allowed the invasive Sea Lamprey to spread throughout the lakes, were it decimated indigenous fish populations such as the Lake Trout. Another invasive was the Alewife (river herring), that had no natural predator, thus exploded in population. In the 1960's the Alewife colonized the Lakes and became abundant mostly in lakes Huron and Michigan. They often had Summer die offs, which washed up on the shorelines.

These die offs presented the stench of decay that closed beaches and resort communities. The economic losses were staggering throughout the lakes communities. To address this disaster, Dr Tanner, a University of Michigan Biologist proposed that a predator, the Coho salmon from the West Coast, be introduced into Lake Michigan to control the alewife population. Dr. Tanner's experiment was a huge success which eventually led to state salmon/trout hatcheries and annual Spring fish plants throughout the lakes.

Today, Lake Michigan is a world class salmon/trout fishery. The invasive Alewife, and the introduction of the Coho salmon has transformed once industrial waterfronts into recreational harbors and revitalized towns around the Great Lakes. Tourists have flocked back.

Charter fishing fleets have sprung up throughout the lakes because of the great fishing. Waukegan, Illinois, once an avoided industrial area, has been revitalized and was declared, in the 1970's by West Port, Washington Captains, the Fresh Water Salmon Capital of the Great Lakes.