History+of+Zebra+Mussels

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The Zebra mussel, // Dreissena polymorpha //, is native to Russia and has been living in both western and central Europe for over 200 years. It is believed that Zebra mussels entered the Great Lakes aboard a commercial cargo ship in 1988 in Lake St Clair. They traveled from the Black Sea and entered the lakes when their larval stages were released during a ballast exchange. They are now found in at least 20 of the continental United States. (1)

Timeline of // Dreissena polymorpha, // Zebra Mussels, in Lake Erie:[]

Map showing a timeline of // Dreissena polymorpha // across North America:[]  Video Clip on [|"How they got into Lake Erie?"]

The zebra mussel gets its' name from their stripped appearance. They grow anywhere from 1/4 to 2 inches in length. (2) They are filter feeders that can filter up to 1L of water a day. (4) Egg production in female zebra mussels starts when water temperature at 13 degrees Celsius. A mature female can produce anywhere from 40,000 to 1,000,000 eggs in one season. The eggs fertilize and hatch within a few days. The larva that hatch are called veligers and the drift in the current for three to four weeks. The veligers will die if they do not attach to a hard surface. 95% of these veligers do die. (5) After a month they turn into the two shelled mussels and become sexually mature after just a year. The average life span of a zebra mussel is five to six years old but they traditionally only live to be three years old in Lake Erie. These mussels can form beds on hard surfaces with their byssal threads of up to 70,000 mussels.  REASONS THAT ZEBRA MUSSELS ARE SO SUCCESSFUL: 1. Invading is an escape from natural predators: Lake Erie does not have nearly as many natural predators to feed on the zebra mussel. The round goby and a few whitefish are really the only fish feeding on them as well as some birds.

2. The ability to build a population quickly: Zebra mussels can produce one million eggs during one reproductive season. Even if their predators were numerous, this is still a large number to keep under control.

3. Their strong dispersal powers: This might be its strongest factor. During the veliger stage they just passively float downstream, the yearling phase allows them to detach and drift. Finally the adult stage attaches to boats and slow moving objects. These stages not only allow them to survive but makes them great "invaders."

4. They can out-compete the native species: The native mussels don't stand a chance. Even if they could compete, these zebra mussels will attach to the native mussels shells with colonies in the thousands and smother the native mussel.

5. They adapt easily to their new environment: These mussels, like most, have the ability to adapt to many chemical and biological changes that come along.

6. They have a broad, flexible diet: There is an immense food source for the zebra mussel in Lake Erie. Feeding primarily on phytoplankton allows them to always have a food source. They also produce massive amount of phosphorus in their pseudofeces which can cause algal blooms. This creates even more food.

7. They have had help from humans: They were brought here in a boat by accident. They are so small and seemingly harmless that they have been traveling with us around Lake Erie and other waterways for year now.

Video Clip: [|Zebra mussels]

Video Clip: [|Zebra mussels in Lake Erie]