the zebra mussel: Did you know?
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The zebra mussel is a small freshwater bivalve about the size of a fingernail and is named for the zigzag lines on the shell. It was originally found in the Caspian Sea and rivers that flow from the Ural Mountains in Russia, but has been accidentally transported on ships to many parts of the world where they are now considered an invasive species. Zebra mussels attach themselves by byssus threads to lake and river bottom surfaces such as silt, rocks, and shells. They are filter feeders, filtering food and other particles from the water and excreting waste and non-edible matter. Zebra mussels can kill native freshwater mussels by: (1) attachment to the shells of native species which can kill them, and (2) outcompete native mussels and other filter feeding invertebrates for food. The presence of zebra mussels in Lake Erie and other bodies of water across the U.S. has shown mixed effects. Waste from feeding provides nutrients for bottom-feeding fish, but the clearer water allows light to penetrate deeper, allowing more algae and other aquatic plants to grow. When these plants die, the decaying matter fouls the water and washes up on shore in large quantities. The interactive distribution map below shows how this species has spread in the Great Lakes area since 1987. Credits:
Project's Library of Life Lead: Andrew Hipp, Morton Arboretum Great Lakes Invasive Species Card Image: U.S. Fish and Wildlife Service 3-D Imaging: Anne Basham More information: http://www.dnr.state.mn.us/invasives/aquaticanimals/zebramussel/index.html |
