In their report to the Board the Waterfront Committee proposes to expand education through the CSA website, Ecology Fun classes, the CSA welcome packet, and other means on the following topics:
1) The fragility of our regional ecosystem
2) The need to adopt measures to prevent the introduction and spread of aquatic invasives in Crystal Lake and surrounding waterways
The Crystal Lake Watershed Association (CLWA) asked us to pass along this information about the invasive Eurasian Watermilfoil (EWM) to the CSA community. The CLWA Board is starting to discuss options and wants to inform all interested groups about possible ways to approach this invasive plant that has been present for 25 years. They will be gathering opinions and answering questions before the CLWA Board decides on the best treatment option in 2020. Even though the CSA Crystal Lake beach doesn’t have any known EWM they want our community to be informed. EWM appears to be expanding it’s hold in Crystal and the CLWA feels it is time to consider treatment options, of which there are many. We would like the CSA Community opinions and thoughts as well. Should we treat, and how much & how often? Please see the story below with more information.
Invasive Eurasian Watermilfoil in Crystal Lake, Benzie County 2019
The Crystal Lake & Watershed Association (CLWA) has compiled a 3 year study of our lake to update our knowledge of the aquatic plants which are so beneficial to the health of the lake ecosystem. We have found only one invasive plant from the Caspian Sea, Eurasian Watermilfoil (EWM), located primarily in the east end. It was undoubtedly introduced at least 25 yers ago by itinerant fisherman or recreational boaters at the Beulah boat launch where it has established a vigorous population of high density extending along the entire drop-off of the east end. There is intermittent colonization along the southeast shore up to and past the DNR launch and around Railroad Point into Onkeonwe Bay. There are colonies established at the Loeb road launch and none found going west from the Disciples of Christ Church Camp on South Shore Rd. The western and northern shore appear to be virtually free. The total acreage is calculated by very accurate drone photography to be 6.05 acres.
This invasive, by way of the St.Lawrence Seaway, has been found in virtually every county of Michigan and efforts to control EWM have become the dominant lake treatment budgetary item of state and local riparian organizations. EWM can out-compete local beneficial aquatic plants, and can effect fish, amphibian and benthic invertebrate populations as well. When it sometimes takes over a lake and extends to the surface, boating, swimming, fishing and all recreational activity can be severely curtailed. Property values can start to decline.
Since EWM appears to be expanding it’s hold in Crystal the CLWA feels it is time to consider treatment options, of which there are many. We would like your opinions and thoughts as well. Should we treat, and how much & how often? Most authorities recommend treatment before it reaches a stage where control becomes difficult. Once established in an inland lake invasive plants and animals (zebra mussels) can only be controlled, not eliminated.
These are the various options to consider:
- Observation - with regular monitoring of extent and change in acreage over time. Expansion of plant mass is usual, although to and fro spontaneous growth patterns do occur for unknown reasons. This has been documented by drone survey.
- Hand Removal - for early plant growth when small; this requires educating riparians on correct identification and is labor intensive but can be effective early on.
- Biologic Control with the Milfoil Weevil - there have been partial successes in the past on some lakes. This often takes years of supplying weevils and they require undisturbed shoreline to overwinter, something which Crystal Lake has almost none left due to shoreline development.
- Benthic Mats-these can be effective for small to moderate growth and require smothering the plants to deprive them of oxygen and sunlight with strong artificial or natural fiber mats like burlap. It is very labor intensive to put down and maintain mats in place and requires time in years for effect. We have preformed this on Crystal on small patches in shallow water and 5-6 years were required to complete the kill. From what we can determine use in deeper water in our large windy lake could be very difficult.
- Diver Assisted Suction Harvest (DASH) - effective and very expensive with large ongoing labor expense to pay divers to daily hand pull and place plants in the underwater suction machine run by operators in the boat above. This system disturbs the bottomland and has therefore been criticized for potentially allowing more invasive plant establishment which can favor disturbed soil.
- Mechanical Harvesting - this is for lakes overtaken by massive plant growth to allow temporary use of the top layer of water for short periods before plant growth returns. A distinct disadvantage for EWM is spreading by fragmentation and rooting of loose segments of plant. So in fact it spreads the milfoil every time it is cut.
- Herbicides - the most widely used treatment for milfoil, it is quick ,relatively less expensive than other methods , especially for smaller plant masses, and effective in controlling but not eliminating the invasive plant. It usually requires two treatments per year in our climate and is professionally applied by permitted companies only after permission is given of involved riparian landowners. Monitoring for effect over time is required and there are many lakes that have a regular program of use for control. The specific agents used for milfoil, 2, 4D or Triclopyr do not affect the native plants of Crystal Lake. We have seen more accurate placement and potential less use of product with the addition of drone supervision.
Please direct questions to: