Page "Sea lamprey" Paragraph 2

Sea lampreys are considered a pest in the Great Lakes region.

The species is native to the inland Finger Lakes and Lake Champlain in New York and Vermont.

It is not clear whether it is native to Lake Ontario, where it was first noticed in the 1830s, or whether it was introduced through the Erie Canal which opened in 1825.

Improvements to the Welland Canal in 1919 are thought to have allowed its spread from Lake Ontario to Lake Erie, and while it was never abundant in either lake, it soon spread to Lake Michigan, Lake Huron, and Lake Superior, where it decimated indigenous fish populations in the 1930s and 1940s.

They have created a problem with their aggressive parasitism on key predator species and game fish, such as lake trout, lake whitefish, chub, and lake herring.

Elimination of these predators allowed the alewife, another invasive species, to explode in population, having adverse effects on many native fish species.

The lake trout plays a vital role in the Lake Superior ecosystem.

The lake trout is considered an apex predator, which means the entire system relies on its presence to be diverse and healthy.

With the removal of an apex predator from a system, the entire system is affected.

The sea lamprey is an aggressive predator by nature, which gives it a competitive advantage in a lake system where it has no predators and its prey lacks defenses against it.

The sea lamprey played a large role in the destruction of the Lake Superior lake trout population.

Lamprey introduction along with poor, unsustainable fishing practices caused the lake trout populations to decline drastically.

The relationship between predators and prey in the Great Lakes ' ecosystem then became unbalanced.