The trailering and passage of boats from one body of water to another has significantly contributed to the rapid spread of zebra mussels. Recreational boaters, anglers, and commercial barges all need to take great care to avoid the transfer of zebra mussel "stowaways."
The smaller the mussel, the more likely it is to be inadvertently transported. Although an adult mussel can survive for a week or more in a cool, moist, shaded area, smaller mussels and veligers cannot survive out of water for as long. Veligers can die quite quickly when exposed to drying or the sun. Boats that have been in the water for more than 1 or 2 days may have mussels attached to their hulls, anchors and chains, trailers, equipment, and engine drive units.
More often the mussels are found attached to the aquatic plants that have been snagged by props or drive units. These are easily transported from water body to water body, and are naturally a moist and shaded environment for the mussel to remain alive in. The zebra mussel veliger can be inadvertently transported in live wells, in bilges, within the engine cooling systems, and in bait and collection buckets.
If you look closely, you will be able to detect a dense layer of zebra mussels attached to the shaft of the aquatic plant.
Zebra mussels settle on aquatic plants that can be caught on props, anchors, chains, and drive units and can be accidentally transported from an infested water source to an uninfested one.
Weeds such as these may contain zebra mussels and could easily be transported from lake to lake on props and drive units. Once relocated, they could easily establish a dense population.
Following the guidelines below will not only help to slow the spread of the zebra mussel across North America, but will help to prevent zebra mussel fouling of equipment and avoid potentially expensive removal procedures.
Various federal and state agencies recommend taking the following precautions to minimize further unintentional zebra mussel introductions into currently uninfested waters.
Always examine a boat for adult zebra mussels immediately after exiting a body of water. Even if none are visible, rinse the boat thoroughly with fresh water. Rinse the boat at the launch, taking care to rinse the bottom and any crevices thoroughly. This will dislodge any mussels that may have settled on the boat. (The high pressure jet sprayer of a car wash is more efficient and time-effective for the removal of mussels.) If possible, it would be ideal to let the boat dry out for a week, as this should kill any of the remaining mussels.
Take care to drain bilges and any live wells, including the engine cooling system, immediately after exiting a body of water. If it is necessary to maintain the live well until later, pour a small amount of chlorine-based bleach into the well, and drain after 30 min. If possible, do not drain the well in an area where the water will enter another watershed.
Vigorously rinse any gear that has come into contact with lake and river water with fresh water prior to use in another habitat. Ideally, rinse or wipe sampling gear such as plankton or drift nets, sieves, or probes with hot water or a chlorine-based water solution to ensure that any veligers are killed. If these are not options and duplicate sets of gear are available, let one set of gear dry out while the other is in use.