Invaders
Many non-native plants, animals and microscopic organisms have been introduced into the Great Lakes since the early 1800s, either accidentally or intentionally. Many non-native species are considered invasive, as they are free from natural predators, reproduce rapidly and aggressively compete with native species.
Invasive species disrupt the aquatic food web by reducing habitat or food for native species and/or by preying directly upon native species. Invasive species are often called “biological pollutants.” Invasive species can affect property values, and influence economies of water-dependent communities. They are costly to manage and have led to a severe loss of biodiversity in Michigan, the Great Lakes region and throughout the world.
A few examples of what happens when invasive species move in:
- The entire Lake Trout population was on the verge of crashing after the sea lamprey invasion until biologists developed ways to keep the lamprey under control.
- The hungry, aggressive Round Goby feeds on the eggs and fry of game fish, stressing the native populations.
- Invasive purple loosestrife and phragmites spread quickly — firmly taking hold in wetlands, rendering some land unusable along waterfronts and squashing biodiversity. Phragmites are especially good at knocking out other plants in their growth area, secreting a form of acid that proves lethal to those nearby.
- Eurasian Watermilfoil and Frogbit choke out waterways, which makes the areas unusable to boaters and swimmers. Some invasive plants rob the water of oxygen, causing fish kills.
- Industrial plants – including water plants that provide drinking water for cities – have reported significant reductions in pumping capabilities and occasional shutdowns due to zebra mussels. The mussels attach to hard surfaces and colonize on structures, such as boats, water intake pipes, turtle shells, etc.
- Industry, government and citizen groups spend tens of millions of dollars on invasive species control every year.
To learn more, see: what you can do to help
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