The zebra mussel has become prevalent in the Great Lakes and is a very invasive species.
They were first detected in Canada in the Great Lakes in 1988, in Lake St. Clair. They are thought to have been inadvertently introduced into the lakes by the ballast water of ocean-going ships that were traversing the St. Lawrence Seaway. Another possible, but unproven, mode of introduction is on anchors and chains. Since adult zebra mussels can survive out of water for several days or weeks if the temperature is low and humidity is high, chain lockers provide temporary refuge for clusters of adult mussels that could easily be released when transoceanic ships drop anchor in freshwater ports.
Since their arrival in the Great Lakes, they have covered the undersides of docks, boats, and anchors as can be seen on the Kristy-Lyn II now in dry-dock at Southampton Harbour.
They have also spread into streams and rivers throughout the U.S. and, in some areas, they completely cover the substrate, sometimes covering other freshwater mussels. They can grow so densely that they block pipelines, clogging water intakes of municipal water supplies and hydroelectric companies. Zebra mussels do not attach to cupronickel alloys, which are a combination of copper and nickel, that can be used to coat intake and discharge grates, navigational buoys, boats, and motors where the mussels tend to congregate.
According to sources zebra mussels are also believed to be the source of deadly avian botulism poisoning that has killed tens of thousands of birds in the Great Lakes since the late 1990s.
Since their first appearance, zebra mussels have widely spread to a number of waterways, including Lake Simcoe, Lake Huron, the St. Lawrence and in states that include Ohio, Missouri, Tennessee, Colorado, Arkansas and in 11 lakes and fiver river basins in Texas.
In scientific reports, a female zebra mussel begins to reproduce within 6–7 weeks of settling and can produce 30,000 to 40,000 eggs in each reproductive cycle, and over 1 million each year. The free-swimming microscopic larvae, called veligers, then drift in the water for several weeks and settle onto any hard surface they can find. Zebra mussels also can tolerate a wide range of environmental conditions, and adults can even survive out of water for approximately seven days.
They not only damage harbours, waterways and ships and boats but also water-treatment and power plants. Water-treatment plants are most affected because the water intakes bring the microscopic, free-swimming larvae directly into the facilities. Zebra mussels also cling to pipes under the water and clog them.
Since zebra mussels cling to the motors of boats, boat-owners should follow a few steps prior to putting their boats into a new lake and after removing their boats from infected lakes to stop the spreading of the species.
They should make sure to inspect their boat, trailer, and other recreational equipment that have been in contact with water, remove all mud, plants, or animals, drain all bilge water, live wells, bait buckets, and all other water from their boats, engines and equipment. They should then wash all parts of their boats, paddles, and other equipment that have been in contact with water, and dry their boats and trailers in the sun for five days before launching into another body of water. This is important because adult zebra mussels are able to close their shells and may survive out of water for several days. When washing their boats, boat owners should be sure to wash with warm, soapy water as well and it is said that *vinegar will kill the mussels.
*In a project funded by the New York State Department of Environmental Conservation Award Number 69018 and published by the Regional Euro-Asian Biological Invasions Centre (REABIC), Matt Albright and Holly Waterfield of the SUNY Oneonta Biological Field Station aided in the use of laboratory space and equipment with experiment design aided by advice from Ashlie Watters and valuable insight provided by three anonymous reviewers, it was found that a distilled vinegar solution of 25% was effective in killing zebra mussels. To read the study, CLICK HERE.
If these precautions are followed, it is hopeful that the spread of the species should slow down, and more lakes can be saved from contamination.