3 days ago
Pink water at Bear Lake? Here's how this study aims to curb invasive plant species
BEAR LAKE STATE PARK, Utah (ABC4) — Bear Lake was looking a little pink recently, but don't worry, it wasn't the infamous Bear Lake Monster. Rather, it's part of a study to learn more about eliminating an invasive plant species.
Jessie Danninger, DNR Bear Lake program manager, said it's part of a team-up with Mirella Ortiz, an associate professor in weed science at USU. The purpose of the study is to better understand the effectiveness of DNR's aquatic herbicide treatments for Eurasian watermilfoil, an aquatic noxious weed.
In the study, pink dye is poured into a few spots throughout the lake. A fluorometer is then used to measure how much dye remains in that location as it dissipates over time.
Ortiz said the dye that is used is known as Rhodamine Water Tracer dye, which is non-toxic and considered to be the safest option for this type of study.
Danninger explained that the study will help the team better understand how the herbicide disperses in the water to see if it's effectively reaching the target weeds, which will better inform decisions for the management plan going forward.
'Not much is known about the currents at Bear Lake, so we are hoping to learn a bit more about how the water is moving. We want to make sure our herbicide treatments are as effective as they can be, and understanding what happens to the chemical once it's sprayed in the water column is key,' Danninger said.
Danninger said the public should remember to clean, drain, and dry all watercraft and gear to prevent the spread of Eurasian watermilfoil.
'Eurasian watermilfoil is an extremely invasive aquatic weed found all around Bear Lake, and it can spread from just one tiny fragment. Thoroughly cleaning watercraft (motorized and non-motorized) and gear can help prevent the spread. It's also important not to navigate watercraft through dense vegetation as the weeds can entangle props, impellers and paddles, creating a safety hazard, as well as providing the weeds with the perfect opportunity to spread,' she said.
At this time, the pink dye has already dissipated, so visitors shouldn't expect to see it. A second round is expected to begin soon.
According to DNR, Eurasian watermilfoil was first found in Bear Lake in 2019 and was listed as a noxious weed in 2024. It has small, feathery needles, which reproduce and spread rapidly. This can form thick mats that choke out fish and other native plant life, blocking out the sun, as well as lake access for boats, jet skis, and other recreationists.
The species spreads through fragmentation. DNR works to monitor and treat this species annually.
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