The Bear Lake Monster is Alive and Well-hunt milfoil

 The Bear Lake Monster is Alive and Well 

Growing in the waters of Bear Lake is an invasive aquatic weed that threatens recreation, fish habitat and water quality. With long stems reaching up to 30 feet long, and feather-like green leaves, Eurasian watermilfoil (Myriophyllum spicatum) creates dense mats that can impede recreation. One small fragment of this plant can break off, settle in the sediment and establish roots anywhere around the lakeshore. It thrives in marinas, where it is protected from wave action and boat props chop up the stems to produce hundreds of new plants. Oftentimes, you can look down through the crystal clear water of Bear Lake and see this monster growing on the lake bed in depths up to 40 feet. Its native relative, northern watermilfoil (Myriophyllum sibiricum), also grows in Bear Lake. The Eurasian and native species can hybridize, creating an herbicide resistant weed that would pose an even greater threat to the lake. There are no hybrids growing at Bear Lake yet, but it is important that we prevent them from establishing.

Eurasian watermilfoil was first found in Bear Lake in 2019 by the Idaho State Department of Agriculture and was confirmed on the Utah side later that year. Utah Forestry, Fire & State Lands (FFSL) put together a treatment plan for this invasive weed in 2020, and have been treating it with an aquatic approved herbicide (ProcellaCOR) ever since. Each year, staff has monitored and treated in various areas around the lake, focusing primarily on marinas, boat ramps and areas with high recreation use. This past summer, FFSL staff partnered with Bear Lake Watch and Utah Department of Agriculture and Food to put in massive efforts to survey the entire Utah shoreline for the first time. Because of this effort, FFSL was able to treat nearly 200 acres of open water for milfoil, doubling the amount of acres that had ever been treated on the Utah side in the past. The 5 marinas on the Utah side of the lake were also treated for both Eurasian watermilfoil and another invasive weed, curly leaf pondweed. In total, almost 220 acres were treated for aquatic invasive species on the Utah side last year.

This coming summer, FFSL plans to use sonar to map underwater vegetation and reduce the number of man hours needed for surveying. This will also be a great tool to map the spread of the invasive weeds year after year. In addition, Mirella Ortiz, a professor and researcher from Utah State University has partnered with FFSL to investigate which herbicides are most effective specifically for Eurasian watermilfoil at Bear Lake. The results of her work will help managers decide which herbicide(s) would be most effective in Bear Lake’s waters.

As recreationalists and concerned community members, there are some things that you can do to help prevent the spread of this invasive aquatic weed, as well as others. Just like for quagga mussels, the best practice is to CLEAN, DRAIN, DRY. Ensure that your boats, jetskis, kayaks, paddleboards, and fishing gear are cleaned of all vegetation and mud before AND after entering any body of water. If you see thick patches of vegetation in the water, don’t navigate your watercraft through it, and go around if possible. Do your part to prevent the spread of these invasive aquatic weeds and help us protect the Caribbean of the Rockies.

 

Visit our website to learn more about invasive weeds at Bear Lake: https://ffsl.utah.gov/state-lands/bear-lake/invasive-plants/