The Zebra Mussel Zebra Mussels

Description The zebra mussel is a small freshwater mussel. Zebra mussels get their name from the striped pattern on their shells (not all look like this). Usually about the size of a fingernail.

The life span of a zebra mussel is about 4-5 years. An adult female zebra mussel may produce between 30,000 and one million eggs per year. However, only abut 2-5% of those eggs reach adulthood.

Within 2-3 weeks of their birth, zebra mussels “settle” and attach by strong byssus threads to hard, still surfaces such as rock, wood, glass, rubber, and other sessile (immobile) animals.

Zebra mussels are filter feeding organisms; their filter out nearly all the phytoplankton and small zooplankton in an area. Because of their large populations, they can eat the majority of important producers in an aquatic ecosystem.

There are a large number of natural predators of the zebra mussel. The are eaten by crayfish, waterfowl, muskrats and some fish. However, at cool water temperatures, predation rates are very low.

Because of these qualities, zebra mussels have become an INVASIVE SPECIES in many countries worldwide. An invasive species is a species that does not naturally occur in a specific area AND whose introduction causes economic, environmental or harm to human health.

Zebra mussels originally lived in the lakes of Southeast Russia. The first sighting of zebra mussels outside of Russia was in the early 1800s in Europe. They were able to disperse through man-made canals that linked European waterways.

Zebra mussels were first seen in Canada in the Great Lakes in It is believed they were brought here accidentally on the hull of a European ship.

Negative Effects of Zebra Mussels Their shells are very sharp. People’s feet often can be cut by walking in areas of high concentrations of zebra mussels. They also produce foul odors when they decay.

They threaten native fish and wildlife by reducing species of algae and microscopic aquatic animals that are important for the food chain. They also attach to other animals like other mussels and crayfish, making it hard for them to survive.

Their colonies can become so dense and thick that they clog pipes and waterways.

They are an expensive nuisance to boaters and fishermen. They can attach to boats and clog water intake pipes, causing costly repairs.

Once zebra mussels enter an ecosystem, it is very difficult to control them. Their populations grow at a rapid speed. Because their threads are so strong, it is difficult to remove them from objects once they are attached.

The cost of trying to control zebra mussels is extreme – the cost in the Great Lakes alone exceeds $500 million per year.

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Questions 1.What is an invasive species? 2.Why is the zebra mussel considered an invasive species? 3.In what ways do the zebra mussel negatively affect the natural food webs that exist in their aquatic ecosystems? 4.How do zebra mussels negatively affect us? 5.Do you think humans should try and make zebra mussels extinct?