Watercraft - A Pathway for Aquatic Invasive Species


Much of the ongoing spread of aquatic invasive species (AIS) to inland waters throughout North America can be attributed to the overland movement of powerboats, small commercial and recreational fishing boats, sailboats, personal watercraft, canoes and kayaks, pontoon boats, and other boats that can be towed owerland on trailers. Translocation of organisms by boaters can be intentional (e.g., as bait), but is often unintentional, with invasive species inadvertently carried in bilge water, live wells, and bait buckets. Invasive species can also be entrained on boat exteriors, e.g., entangled on propellers and trailers, attached to other entangled organisms. Thus, every time a boat is transported overland after use in an invaded waterway, there is the possibility that it will transfer AIS to uninvaded waterways.


Overland transport of small-craft boats is thought to be responsible for the spread of spiny waterflea (Bythotrephes longimanus), Eurasian watermilfoil (Myriophyllum spicatum), and zebra and quagga mussels (Dreissena spp.). These organisms are known to have considerable negative effects on the aquatic ecosystems they invade, with impacts including damages to fisheries, interference with raw water usage, decreased property values, extirpation of native species, and threats to human health.


clean, drain, dryboat washer

*Note: The text above was excerpted from, "Aquatic Invasive Species Transport via Trailered Boats - What is Being Moved, Who is Moving It, and What Can be Done," J.D. Rothlisberger, W. L. Chadderton, J. McNulty, and D.M. Lodge, American Fisheries Society, 35(3):121-132.

Wakeboard Ballast


Aquatic nuisance species often hitch rides to other bodies of water on the boats, trailers, and equipment that people transport from place to place. Boaters and anglers can inadvertently transport aquatic invasive species in bilges, ballast water, live wells, or any other equipment that holds water. It is the responsibility of the boat owner/user to ensure ballast tanks and bags are drained and dry when moving the boat between water bodies.



What is ballast?

A ballast tank is a compartment within a boat, ship or other floating structure that holds water. Adding water (ballast) to a vessel lowers its center of gravity, and increases the draft of the vessel. A ballast tank can be filled or emptied in order to adjust the amount of ballast force. Small sailboats designed to be lightweight for being pulled behind automobiles on trailers are often designed with ballast tanks that can be emptied when the boat is removed from the lake or reservoir.

Wakeboard Ballast Tanks and Bags

Ballast water taken into a tank from one body of water and discharged in another body of water can introduce aquatic invasive species. Wakeboard boats are V-drive boats, i.e., an inboard boat with the engine placed backwards in the rear of the boat. More weight is in the back of the boat  to make wakes larger and steeper. Some wakeboard boat models are direct drive boats in which the engine is in the middle of the boat. Most wakeboard boats will have features, such as ballast, wedge and hull technology, that help to create large wakes. Ballast can take the form of hard tanks or soft bags, which are filled with water from the body of water the boat is being operated on.


Ballast bags are used to enhance the surf wake made by a wakeboard boat, and are typically filled and drained with a pump connected to a hose. Some ballast bags are designed for integration into an automated ballast system already in place in the wakeboard boat. When filling a ballast bag, it is recommended in most owner manuals  to “place the pump in the water keeping it clear of weeds and sand.” When draining, the instructions direct the boater to “place the hose of the pump over the side of the boat.” Because these bags are impossible to fully drain, if a ballast bag has been used in a water body that has tested positive for aquatic invasive species, it mustbe decontaminated prior to it being used on any other water, unless it has been out of the water for 30 days or more. The water temperature of the decontamination unit must be lowered to 120ºF to prevent any damage to the pump or bags. 

Factory Installed Ballast Bags

All Moomba ballast boats and all but one model of Supra ballast boats have soft ballast bags that have factory installed reversible pumps. They have the same inlet and outlet through-hull drain port located on the bottom of the hull. Almost all of them come with an inboard engine and three ballast bags: two bags are located on the sides of the engine compartment and one in the center floor compartment. All of these bags have a quick connect on the intake and discharge hoses to easily remove them. Only one Supra model, the 242, 2011+, has one hard tank located under a ballast bag.

Other Examples of Ballast Bags

There are many other examples of ballast bags, many of which are uniquely shaped for specific wakeboard boat models.



What is the risk?
Watercraft Type
Risk Level
House boats, cabin cruisers, ski boats, and wakeboard boats with ballast tanks           Very high biological risk
Large open boats, sailboats, ski boats, and wakeboard boats with no ballast tanks, personal watercraft Medium to high biological risk
Simple boats - open hull, single motors, no interior containers or compartments Low biological risk
Canoe, kayak, windsurfer board, sail board, belly boats, rafts, float tubes, and inner tubes Very low biological risk