Invasive Species

With a big appetite, these fish eat 40% of their body weight a day, discharging about half their undigested food back into the water, skewing the nutrient levels, and increasing the chances of toxic algae blooms.

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They have no natural predators, and reduce the resources and habitat quality for native species.

These fish have poor digestive functioning, and need to feed constantly. They have no natural predators in North American lakes, and threaten the habitat for native species. They are not yet documented in the Great Lakes, but scientists are concerned about their ability to travel.

A high reproductive rate and the propensity to destroy native fish habitat and predate on their eggs makes the common carp a serious ongoing threat in all the Great Lakes. 

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They disrupt the lakebed  through extensive feeding, and by disrupting the sediment, impeding underwater plant growth.

Breeding in large colonies, zebra mussels can overtake fish-spawning habitats as well as recreational areas.

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They over-filter the water, making it unnaturally clear, so that sunlight reaches the lakebed and disrupts the growth of underwater vegetation. This process increases the chance of toxic algae blooms.

These prolific breeders can breed up to a million eggs in a season, greatly dispersing their population, and causing severe damage to the ecosystem, and to boats and docks. 

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Like zebra mussels, they filter plankton, altering the food web and allowing too much sunlight to reach new depths in the lake.

Through breeding several times a year, and by aggressively feeding on small aquatic organisms, round goby outcompete native fish for food.

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They also carry a strain of botulism from eating zebra mussels that kills native birds and fish that eat the goby. They are so destructive, it is illegal to posses a live one.