Eurasian Watermilfoil a Growing Threat to the Lake

The Facts

In 2012, the Farlain Lake Community Association discovered a small isolated patch of Eurasian Watermilfoil (EWM) at the Southwest end of the Lake - a  non-native and very invasive weed.  This aquatic plant will quickly establish itself throughout the Lake unless aggressively controlled.  If allowed to spread, it will impact fish and wildlife, restrict recreational activities, and affect community real estate vaues.

Why is EWM a Threat?

This non-native plant forms thick underwater strands of tangled stems and vast mats of vegetation on the water's surface, especially in shallow lakes like Farlain Lake.

Why is EWM a Problem?

Once established, dense colonies of EWM makes boating, fishing, and other recreational activities difficult. EWM will alter the lake’s ecosystem by choking out important native plants, thus harming fish and wildlife habitat. EWM promotes algae growth.

Property owners can expect increased costs to keep boat channels open. Boat owners could incur increased boat repair and maintenance costs. In severe conditions, EWM can depress real estate values.

How Widespread is EWM and How was it Introduced to the Lake?

The invasive aquatic plant species is limited to a small area of the lake. The approximate one acre area of dense vegetation is located in an isolated area near the western shoreline.

 It is unknown when EWM was introduced to the Lake. It was discovered during  the FLCA’s submerged aquatic plant study of the lake during the summer of 2012. The plant has now spread throughout the Lake.

While EWM could have been transported to Farlain Lake through human activity, EWM could have also been introduced to the lake through natural means such as waterfowl or animals.  EWM is primarily transported from one body of water to another on the bottom of boats and boat trailers, and anglers emptying bait buckets into the water.

How Will EWM Spread Throughout the Lake?

EWM primarily reproduces through plant fragments (leaf parts and stems) rather than through the dispersion of seeds. Accidental cutting the EWM plants create plant fragments which can be transported by watercraft to another part of the lake. EWM plants also naturally ‘auto fragment’ at the end of the growing season creating plant fragments. The fragments float and can be carried by wind and wave action to new areas where the plant fragments settle to the lake bottom to take root and grow. One small plant fragment has the potential to colonize 20 new EWM plants.

Can EWM be Controlled?

Once established EWM can never be fully eradicated, and control is costly. Left unchecked, EWM has the potential to render the lake unusable.

What is the Plan?

The FLCA Board of Directors has considered a number of EWM management alternatives. One option…no action….is a gamble. The infestation may continue from year to year and spread throughout the lake. Because EWM is an aggressive species that out-competes and eliminates natural aquatic plants creating EWM milfoil beds which become denser over time, it is imperative that the  EWM be controlled before it becomes a major lake-wide issue.

Go to Dealing with the Threat for details on the current Save Our Lake Campaign and the plans for battling this weed in 2017.