Eurasian water-milfoil is a very invasive water plant. The plant was introduced into North America through the aquarium trade in the 50’s. Over the early years the plants spread from aquariums to lakes, due to the lack of controls regarding the disposal of aquarium contents. It then spread between lakes by fragments attached to boats and boat trailers (or any other aquatic equipment). This is currently the primary source which is causing environmental damage across North America. Fragments can stay alive for weeks out of water if they happen to stay moist. Although this invasive water plant has been around for decades, it has become a major issue across North America over the last 5 to 10 years, adversely affecting many 10s of 1000s of populated lakes. One of the reasons that this plant is so invasive is that it spreads through stem fragmentation; e.g. if a single plant is cut into 5 pieces, it will grow 5 more plants from those pieces. When it infests an area, it can form thick underwater stands of tangled stems and vast mats of vegetation at the water's surface.
The dense growth of the milfoil displaces the indigenous species and prevents fish from laying eggs in the infested area. This reduces the indigenous plant growth, negatively affects fish populations and makes recreational use in those areas difficult or impossible. ABV-7 considers Eurasian Milfoil their number-1 environmental issue to be managed in their region.
A significant increase in the milfoil growth rate can occur when it spreads into high boat traffic areas on lakes and rivers. These areas include boat launch zones and shallow waterways with high traffic. These areas are significantly contributing to the growth rate, since each powered boat passing through the infested areas has the potential to chop up hundreds of milfoil plants with its propeller. This then leads to the re-growth of hundreds of new plants