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Coon, T. G., 1993. Safe Use Of Zebra Mussels In Classroom And Laboratories, Michigan State University, Ohio State University, Michigan Sea Grant College Program, Ohio Sea Grant College Program A Great Lakes Sea Grant Network fact sheet produced by the Michigan and Ohio Sea Grant College Programs Safe Use Of Zebra Mussels In Classroom And LaboratoriesZebra mussels (Dreissena polymorpha) were accidentally introduced into North American waters in the mid-1980s. Since that time, they have spread throughout the Great Lakes region and into the Mississippi River basin. They have attained considerable notoriety because they are extremely prolific and move into new regions fairly quickly, but most importantly because they clog water intakes and plumbing systems and foul boat hulls, docks and other submerged surfaces. Some of the features that make zebra mussels a nuisance also make them interesting for use in the classroom. Adult mussels can be kept alive easily in a simple aquarium system for at least several days, and they readily exhibit interesting facets of animal behavior, physiology and ecology. However, zebra mussels are not native to North American waters and they can be a costly nuisance. Because of this, it is important to use extreme caution when using them for class instruction. It is imperative that classroom use not result in the release of live mussel either adults or larvae into lakes, streams or plumbing systems, either by accident or by intent. To understand the basis for control measures, it is important to understand a few aspects of zebra mussel biology, specifically, their means of transport and their tolerance of adverse conditions. Adult zebra mussels attach themselves to hard substrates such as rocks, other mussels, logs, boat hulls and the inner walls of pipes with secreted fibers called byssal threads. It is when these attached mussels accumulate (up to hundreds of thousands per m2) that they become a nuisance to industries, municipal water suppliers, power plants and other water users. Adult mussels can survive being detached from their substrate, and they can crawl along the substrate to find new attachment sites. In fact, adult mussels will readily detach themselves from a substrate, crawl to another substrate and reattach. The primary means of dispersal for zebra mussels is not the movement of adult mussels, however. Rather, zebra mussels spread as their planktonic larvae are carried by water currents into previously mussel-free habitats. Though this passive transport can only occur downstream in rivers, it assures broad dispersal of mussels within a lake basin. However, zebra mussels can and do move upstream and against lake currents-with human help. For example, larvae can be carried in the bilge water of boats (including pleasure craft) traveling upstream or being transported over land to upstream waters. Adult mussels attached to boat hulls, trailers, anchors or ropes can also be transported upstream by boat travel. Adult mussels, in particular, can survive out of water for days simply by closing their valves and slowing their metabolic processes. These "opportunistic" characteristics make it imperative that people take precautions to prevent the spread of zebra mussels into waters where they could not go without our assistance. For example, zebra mussels have effectively surrounded lower Michigan by colonizing Lakes Erie, St. Clair, Huron and Michigan. However, they have only been found in a few inland water bodies. These invasions occurred when boats from the Great Lakes were transported to these inland lakes. Even in areas where zebra mussels are established, it is important to use them with caution in the laboratory. For example, a flow-through aquarium that drains into a sink or floor drain could introduce mussels into plumbing and eventually clog the plumbing and require expensive repairs. We recommend several preventative measures for teachers and students to follow to ensure against introducing zebra mussels into plumbing or inland waters. First, know the current status of zebra mussels in your area. You can get this information by calling your state's Sea Grant office or natural resources agency or the zebra mussel hotline operated by New York Sea Grant. Are zebra mussels present in the lakes or streams around your school? If mussels are not present in your area's surface waters, then you should not transport them to your lab or classroom from infested areas. Transportation across state lines is generally illegal and many states forbid transporting them anywhere within the state. If there are no mussels in your area, do not use them in your class but go to a site that is already infested to study them. In other words, confine your use of zebra mussels to field trips to areas where they are already present. Do not bring live mussels, water that was in contact with zebra mussels or items that have been in contact with water that contained zebra mussels back to your classroom. The water may contain microscopic larvae, and items with hard surfaces may have tiny post-larval mussels attached. To avoid the risk of introducing zebra mussels to the interior waters of Michigan, Michigan State University researchers have conducted their research with live mussels at F. T. Stone Laboratory, Ohio State University's biological field station on Lake Erie. , if you do use zebra mussels, water or items that have been in contact with zebra mussels in your classroom, quarantine them from contact with your plumbing system and the surface waters in your area. In other words, keep the mussels and water in closed systems. , treat any items that have been in the water with mussels (such as gravel, rocks, filters, siphon tubes, plants, etc.) with a 10% solution of household chlorine bleach before using them again. This will kill any attached larvae, juvenile or adult mussels. Also, be sure to treat any water that has come into contact with mussels before disposing of it. The preferred treatment is a bleach solution (I part full-strength bleach to 9 parts water, minimum 30 minute exposure). Alternatives include exposure to hot water > 40°C (104°F) or hot salt water ( > 3 parts per thousand) for at least 15 minutes or freeze samples at -18 °C (0°F) for a minimum of 24 hours. We recommend using a water-proof bin or tub to soak all items that came into contact with zebra mussels or zebra mussel water and a separate container for discarded zebra mussel water. Keep these containers away from sink and floor drains so that untreated spillage does not escape down the drain. At the end of each day, treat both containers with chlorine bleach or hot water as prescribed above. This will kill any remaining larvae, juvenile or adult mussels. Overnight exposure is more than long enough to kill remaining mussels, as long as concentrations are appropriate. You may want to place several live adult mussels into the treatment water to verify that your treatment is adequate to kill zebra mussels.
The only other appropriate way to dispose of treated water is to pour it over very porous (sandy) soil-far from a surface water body or storm sewer. Zebra mussels and other exotic organisms can be effective teaching tools for a variety of biological topics. However, careless use of any exotic species will likely result in an undesired, costly lesson-both in terms of potential repairs and in terms of adverse ecological effects on your local aquatic ecosystems. To avoid this, use any exotic species with caution and take all necessary precautions to prevent release of live exotics into aquatic or terrestrial ecosystems! Contact: T. G. Coon, Michigan State University l3 Natural Resources
Building, East Lansing, MI 48824 or your local Sea Grant
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