Zebra Mussels Update -2019

Zebra Mussel Update:

In the fall of 2016, a suspected Zebra Mussel (ZM) was found on a removed dock and verified by the Wisconsin DNR.  McKenzie Lakes Association applied for and received a DNA Rapid Response Grant to assess, monitor for ZM, and to educate the public about the presence of the ZM.  The grant runs for three years and we are in its final year.  The MLA was invited to be part of the ZM Management Team made up of state, federal and county representatives.  The ZM Management Team objectives were to provide guidance and resource management to the local area to help contain and prevent the spread of ZM.

During these last two years MLA was instrumental in passing an amended transport law in Burnett and Washburn counties, where watercraft must be decontaminated before entering or leaving a lake or river.  Our Association also designed and set-up decontamination stations at each of the public boat landings on the three McKenzie Landings.  Volunteers maintain these stations throughout the year, making sure that fresh bleach is always available in the sprayers.

Under the RRG, the MLA set up a monitoring procedure using sample plates to monitor the population of ZM over time.  Volunteers placed 40 sampler plates throughout the three lakes and at the end of the season counted the number of ZM on each plate.  These counts where used to provide a density measurement for each of the lakes.  Big McKenzie (BM) showed a density measurement in 2017 of 10/sq. ft. and in 2018 a density of 55.5/sq. ft.  In Middle McKenzie (MM) during 2017, ZM were found at two different monitoring sites.  Based on this finding MM was designated by the DNR that MM had an established population of ZM.  In 2018, the density was still very low 0.22/sq. ft.  In Lower McKenzie (LM) monitors have yet to find a ZM on any of their monitoring plates.

During 2019, MLA will continue to monitor for ZM using plate samplers, maintaining the decontamination stations and doing watercraft inspections at the public boat landings on BM and MM.  Additionally we will be working with the DNR to do veliger tows, underwater substrate surveys, and this year have added, eDNA.  eDNA analysis is a monitoring method to determine if the DNA of ZM can be detected in the environment (the water).  The Wisconsin Department of Health has set-up the test to be performed in their laboratory.  Besides the three McKenzie Lakes, lakes in our area designated as highly susceptible to ZM populations will also participate in the testing protocol.

In 2018, ZM adults were collected from BM and sent to the Minnesota AIS Institute at the U of M to determine the possible origin of the ZM.  Testing was completed early in 2019 and the Big McKenzie ZM population more closely aligns with populations found in Wisconsin’s lakes.

As we complete the last year of the RRG, it will be important to continue the programs we have started.  Monitoring using plate samplers should continue to determine the status of ZM population.  Will it continue or will it stabilize or decline over time?  Also, decontaminations stations need to be maintained and used, not only to prevent the spread of ZM from the McKenzie Lakes chain but also to prevent the introduction of other invasive species that could be just as detrimental as ZM or even worse.