Sea Lampreys: Great Lake Invaders

Sea Lamprey are sometimes referred to as the vampire fish. They are jawless fish that have been around before the dinosaurs and have a suction cup mouth with over 100 teeth. The teeth are used to attach to other fish. Their tongue serve as a file that drills holes into the fish to enable them to suck out their blood.  Originating from the Atlantic Ocean, an area in which they were not a problem, have migrated to the Great Lakes where they cost a whole host of problems. Unforeseen circumstances lead them to the Great Lakes. This has created a huge problem because these species are invasive and are threatening the lives of the fresh water fish.

            These invasive fish spawn in gravel areas of streams and build horseshoe-shaped nests. Their eggs are laid, fertilized, and hatched. One female can have up to 100,000 eggs. About 10% of them survive which makes up to 10,000 baby lampreys, from a single male-female pair. Amazing numbers. Baby sea lampreys are called larvae and these offspring burrow into the stream bottom where they live for three to ten years as filter feeders. Once they reach five to six inches long in length, they develop a suction mouth, eyes, fins, and a desire for fish blood. These parasites are ready to eat. They migrate to the lakes to feed for approximately one and one half years and then return to the streams to spawn.

            The sea lamprey entered the Great Lakes through shipping canals built in the 1800s, allowing them to migrate into Lake Ontario from the ocean. They were trapped in Lake Ontario because the Niagara Falls stopped them from entering Lake Erie. In 1919, the Welland Canal, connecting Lakes Ontario and Lake Erie, was made deeper for larger ships. This permitted them to swim into Lake Erie by 1921. By 1937, they were discovered in Lakes Huron and Lake Michigan. Unfortunately by 1938 they reached Lake Superior.

            Soon after they invaded the Great Lakes they began to destroy sport and commercial fish species usually Lake Trout. Before it was realized that sea lamprey were a problem, populations of lake trout were eliminated from Lake Huron and Lake Michigan. Steps were taken to prevent this from happening in Lake Superior. Great Lakes fisheries, worth over seven billion dollars, is worth saving. In 1955, the Great Lake Fishery Commission was established by the U.S. and Canada. Both countries have been negatively affected by the invasion of the sea lamprey. Currently, the commission collaborates with many partners.

            The exciting news is the U.S. Fish and Wildlife Service has tested over 6,000 chemicals and found two lampricides which were successful in destroying sea lamprey that has invaded the streams without harming other fish. Applications of the lampricides are conducted by the U.S. Fish and Wildlife Service and Fisheries and Oceans Canada. The U.S. Army Corps of Engineers builds barriers and traps to capture and stop the sea lamprey. The sea lamprey are stopped and captured before they can go to their spawning areas.

            Sea lamprey are known for their powerful olfactory senses and are often referred to as “swimming noses.” They use these abilities to seek mates and spawning streams. Biologists haves used their strong sense of smell as a method of controlling the population. By putting sea lamprey pheromones into the water, the biologists can attract or repel sea lamprey. They can lure them into traps.

            They have been referred to as eels but they are not eels. They are jawless and eels have jaws and a bony skeleton.

            The Great Lakes have been plagued with the invasion of the sea lamprey since the 1930s. One single male-female pair can produce thousands of baby sea lamprey. Lake trout were eliminated from Lake Huron and Lake Michigan by these blood sucking parasites. Before complete devastation of the lake trout population in Lake Superior has occurred, stringent efforts by many partners have come to the rescue. We could find out how to help with this menacing problem and lend a hand. 

Reference

Activity Book: Great Lakes Fishery Commission, (no date). Sea Lampreys: Great Lake Invaders. 

website for further information: www.sealamprey.org

Pamplet: Great Lakes Fishery Commission, (no date). Sea Lamprey: The Battle Continues to Protect our Great Lakes Fishery. 

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