Zebra mussels (Dreissena polymorpha) are small, freshwater mollusks that evolved in eastern Europe and northeastern Asia. According to the National Atlas of the United States, they began appearing in North America in the late 1980s.
Zebra mussels pose a grave threat to native mollusks by over-competing for food, and they also clog water pipes, foul drinking water, create boating hazards and damage piers and other structures. Attempts to eradicate them have been largely ineffective and expensive, but localized control is possible.
Filters are used to prevent mussels from clogging water intake pipes. The filter mesh has to be small enough to prevent mussel veligers (larva) from passing through.
Toxic chemicals, such as chlorine, are also used to control mussel populations. The trick to is modify chemical usage so that it kills only the zebra mussels and not other life forms.
The Massachusetts Department of Conservation and Recreation states that physical removal (scraping them off of surfaces) is the preferred control method. However, physical removal is impossible for large-scale infestations.
One method that has potential is to disrupt the zebra mussel reproductive cycle by using chemicals to control spawning. The problem with this method is that it needs to be specie-specific and not also disrupt native mollusk spawning.