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.

Environmental Consequences

Sea lampreys are an invasive freshwater species in the Great Lakes region. The species is native to the inland Finger Lakes and Lake Champlain in New York and Vermont.

There is some confusion as to whether it is native to Lake Ontario or was introduced there sometime around 1830 when it was first noticed. Many believe it was introduced to Lake Ontario when the Erie Canal was opened in 1825.

After 1919, the sea lamprey 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.

In each lake, it decimated indigenous fish populations by the end of the 1930s and 1940s. Most effected fish species were the lake trout, lake whitefish, chub and lake herring. As a result, these species were eliminated, allowing the alewife, another invasive species, to explode in population, having adverse effects on native fish species.

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.

Sea lamprey

The Sea Lamprey, (Petromyzon marinus), was a significant factor in the collapse of the lake trout and whitefish fisheries in the 1940s and 1950s. However, after implementing the Sea Lamprey Control Program, implemented in 1955, resulted in a 90% reduction in sea lamprey populations.

Sea lamprey is a primitive eel-like fish that feed on the body fluids of other fish by clinging by their mouth and goring though the scales and skin with their tongue. They prey on all species of large fish in the Great Lakes.

Distribution and Feeding

In each lake, it decimated indigenous fish populations by the end of the 1930s and 1940s. Most effected fish species were the lake trout, lake whitefish, chub and lake herring. As a result, these species were eliminated, allowing the alewife, another invasive species, to explode in population, having adverse effects on native fish species.

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.

Efforts at control

The control programs are carried out under the Great Lakes Fishery Commission, a joint Canada-United States body, under management by the Fisheries and Oceans Canada and the United States Fish and Wildlife Service.

Researchers from Michigan State University have teamed up with others from the Universities of Minnesota, Guelph, Wisconsin, as well as many others in a massive research effort into newly synthesized pheromones. These are believed to have independent influences on the sea lamprey behavior.

Researchers are trying to develop defences against the Sea Lamprey by researching the effects of pheromone and how they initiate migratory function. There are two pheromones that are thought to elicit different behaviors that collectively influence the lamprey to exhibit migratory behaviors or spawning behaviors.

Another technique used in the prevention of lamprey population growth is the use of barriers in major reproduction streams of high value to the lamprey. The purpose of the barriers is to block upstream migration of the lampreys to allow for minimal reproduction.