Aquatic Invasive Species (AIS)

Late in the fall of 2017, the BPLA Board was notified by Tim Plude, Minnesota Department of Natural Resources (MNDNR) Invasive Species Specialist, that Eurasian Watermilfoil (EWM) was found directly below the Crosslake U.S. Army Corps of Engineers (USACE) dam and downstream within the Pine River basin.  Based on Tim’s discovery, he inspected the navigable portion of the Pine River via Big Pine Lake to determine how far downstream EWM may exist. Unfortunately, he located EWM in various locations upstream and downstream from the Big Pine Lake inlet but, fortunately, not within the lake itself.

In June 2018, Tim Plude and BPLA Director of Lake Management, Scott Eichhorst, performed a more thorough review of the river channel in and around the lake inlet and found a moderate amount of EWM upstream, smaller quantities downstream, but none within the lake.  The two also found a couple of plants right at the lake inlet which were properly removed and disposed of.  Tim provided Scott with instructional training on how to remove and dispose of any isolated plants found in the future.

Based on these findings, Tim and Scott discussed methods to control and hinder the spread of the plant, especially with regard to the lake.  Basically, EWM in a river is not effectively treatable with herbicides since the river washes chemicals downstream before they can be absorbed by the plants to the point it can kill the root system.  Therefore, the emphasis should be on keeping EWM out of Big Pine Lake and educating all who boat on Big Pine Lake and Pine River of its presence in the river basin.  Tim’s recommendation was to somehow inform all who boat on the Pine River to clean their prop(s) of all aquatic plants before entering or returning to Big Pine Lake. 

As you may know, there is a “No Wake” sign at the junction of Big Pine Lake and the Pine River basin, so that is the location where the prop should be checked for attached plant material.  The correct method is to remove all aquatic plants from the prop, take them back to shore and dispose of them properly, e.g. in the garbage, burn pit, or by drying them out away from shoreline, etc.  EWM should NOT be thrown back into the river/lake, as this will result in the unintentional spread of the plant. EWM has multiple methods of spreading; one in particular is individual leaves/stems floating and finding shoreline where they will re-root.

The BPLA Board will continue to work with MNDNR to perform shoreline inspections, discuss possible treatment/control methods, and identify additional educational information that can be provided. We have begun to explore the possibility of getting both educational information and additional signage from the MNDNR so that all users of Big Pine Lake will be aware of the presence of EWM and helpful in preventing an EWM invasion. 

Please be responsible when exiting the river, as well as, informing any/all boaters you have contact with to clean their prop appropriately.