Objectives
After participating in this activity, students will be able to:
- Name and visually recognize the primary aquatic invasive species of the Great Lakes
- Understand and analyze the negative impacts that invasive species have on the Great Lakes ecosystem
- Explain the ways in which non-native species are introduced into the Great Lakes
Summary
Many non-native species live in the Great Lakes, and some of them have become invasive. These species have established populations, multiplied rapidly, and caused profound and lasting impacts on the Great Lakes ecosystem. Others (such as Asian carp) have caused serious ecological problems in other parts of the country and threaten to enter the Great Lakes. Students will learn about some of the impacts of invasive species and how people can help prevent the spread of these unwanted species.
Background
Many non-native species have been introduced into the Great Lakes since the early 1800s, either accidentally or intentionally. Nonindigenous or non-native species are plants and animals living outside of the area where they evolved. A fraction of these species (about 10%) are considered invasive. Aquatic invasive species are non-native plants, animals and microscopic organisms that have a profound negative impact on an aquatic ecosystem or human activity.
Free from natural predators, invasive species reproduce rapidly in their new homes and compete with native species for food and habitat. They disrupt the aquatic food web by reducing food for native species or by preying directly upon native species. Invasive species are often called “biological pollutants.” They’re costly to manage and have led to a severe loss of biodiversity throughout the world.
In the Great Lakes, zebra mussels and sea lamprey are among the invasive species that have permanently altered the ecosystem, contributed to declines in native species, and impacted sport and commercial fishing. Invasive plants, such as purple loosestrife and Eurasian watermilfoil, have established themselves in many wetlands and inland lakes, respectively, resulting in a loss of native plants and the wildlife that depend upon them.
Many invasive species in the Great Lakes were transported from foreign ports in the ballast water of ocean going freighters. Ships often take on ballast water for better balance, stability, and safety. Today, the United States and Canada require that most ships entering the Great Lakes exchange their ballast water while still at sea to reduce transport and introduction of new species. Other species like sea lamprey entered the Great Lakes on their own when shipping canals were modernized. Still other introductions are the result of accidental releases.
See: Additional details and photos
See: Aquatic Invasive Species Poster Series
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