Invasive species are non-native plants or animals that enter a new environment that they are not native to, often eradicating native species. Invasive species are also known as alien species, nuisance species, or biological pollution. the vast majority of these invaders are transported by the ballast water of oceangoing ships being released, the St. Lawrence Seaway, and off the hulls of boats from a different body of water.
Sea Lamprey
Sea lampreys are a primitive, jawless, parasitic fish. they are native to the Atlantic Ocean and feed of the blood and flesh of fish. In it's parasitic stage just one lamprey consumes over forty pounds of fish! Before the Sea Lamprey invasion in the mid 1900's the lake trout harvest in Lake Superior alone was four and a half million Pounds, in the sixties that number dropped to below five hundred thousand.
Recently scientists have developed many measures of lamprey control and extermination, such as lampreycides (poisen that targets lampreys and not other fish species), barriers, traps, and the sterile male release program. The Sterile Male Release Program captures male lampreys and sterilizes them. Then the males are released to spawn in tributaries, the females release the eggs and the males cannot fertilize them therefor the thousands of eggs remain dead and unborn and the male and female die after spawning
Zebra and Quagga Mussels
Zebra and Quagga mussels were introduced into the great lakes through ship ballast water. They prefer deep cool water much like that found in Lake Superior. in one spawning season a female will produce over one millon eggs! One mussel will filter feed up to an entire liter in just one day, depleting food supplies for native mollusks. these mussels will colonize practically anything in the water including intake systems and other devices, which leads to very costly repairs.
Round Goby
The round Goby is a botom dwelling fish that reaches lengths of up to seven inches. They extremely better equipped to survive than their native counterparts. They are voracious feeders and skilled predators, because of this the native species have less food and the gobies get bigger faster. They are skilled at predator avoidance and they lay close to 5,000 eggs every few weeks or so during the spawnig season. This means they are living longer and producing more offspring than native species. They must be stopped if native small fish are to survive.
Asian Carp
Asian Carp currently have not entered the great lakes but are threatening to, all that is stopping them is a temperary electric barrier in Chicago, Ill.. There are four types of Asian Carp; the black carp, the bighead carp the silver carp, and the grass carp. They were brought to North America to control weed populations in the southern U.S. . Flooding allowed them to escape into the Mississippi River and from ther all over the country. If the carp were to enter the great lakes a lack of predators and huge appetite would leave the population unchecked.
Spiny Water Flea
The spiny flea is actually a crustacean, they are less than half an inch long and most of their length is taken up by a long barbed spine for protection. Because of this barb the flea has few predators. They mate every two months and consume much more plankton than native species.
