June is the New July: Save Wild Trout Warns of Early Algae Blooms Across Jefferson Basin Rivers

(Big Hole River, MT) Save Wild Trout reported widespread algae blooms throughout the Jefferson River Basin in Southwest Montana, marking a troubling start to another hot summer. The early onset of algal blooms underscore the urgent need for expanded water quality monitoring and address nutrient pollution impairing Montana’s rivers. Amidst 500 miles of travel across the Jefferson Basin this past weekend, Save Wild Trout’s Director Brian Wheeler documented extensive blooms on the Big Hole, Jefferson, and Boulder Rivers, along with two fish showing symptoms of head necrosis. Visual documentation of the algal blooms and diseased fish were submitted to the Montana Department of Environmental Quality (DEQ) and Fish, Wildlife, and Parks (FWP).

The early onset of nuisance algae blooms starting in late June is a troubling indicator of a river system that is unhealthy and on the brink. Algal blooms in rivers and waterways across Southwest Montana, including in the Jefferson Basin, have become more frequent due to warming temperatures combined with elevated levels of nutrient pollution. Typically, algal blooms occur in late July and August during the hottest summer days.   

“June is the new July—a troubling and disturbing reality that doesn’t bode well for our cold-water rivers, waterways, aquatic life, wild trout, and the businesses and communities that depend on them,” says Brian Wheeler, Director of Save Wild Trout. “We can’t protect what we don’t measure. The evidence is right in front of our eyes and backed by science. The facts point to the urgent need to take action, demand accountability, use science to guide solutions, and fight for these rivers’ and wild trout’s survival.” 

Director Wheeler sent the photos of the algae observed June 28 and 29, along with GPS locations, to the Montana Department of Environmental Quality, describing a visible neon bloom that was observed upstream of the High Road Bridge to Glen Fishing Access Site on the Big Hole River, as well as in the upper river near Wisdom—nearly 30 river miles. 

On the Jefferson River, blooms extended from the South Boulder confluence upstream to Hell’s Canyon FAS—approximately 35 river miles—with widespread suspended and floating algae. The Boulder River also showed a dramatic bloom near the Cottonwood Canyon Road Bridge outside of Cardwell. Wheeler noted thick algae growth throughout much of the Big Hole and Jefferson River corridors, suggesting nutrient pollution as a primary driver.

Save Wild Trout is also calling on the public to help document troubling river conditions. “We can’t be everywhere, but Montanans are out on the water every day. If you see something wrong—algae, scummy water, or sick fish—take a photo, note the location, and send it in. You can be our eyes and ears,” Wheeler said. 

Wheeler also observed and reported two sick trout with head necrosis, which have been submitted to FWP through their sick fish reporting portal, which he recommends. Observations in the Jefferson Basin can also be submitted to info@savewildtrout.org 

To expand documentation of potential algal blooms, Wheeler will work with Upper Missouri Waterkeeper to use drone-based monitoring to collect aerial footage of river conditions across remote stretches this week. These drone surveys will provide a broader spatial understanding of the scope and spread of pollution events to complement on-the-ground science efforts. Waterkeeper also calls on the public to help document troubling river conditions at www.UpperMissouriWaterkeeper.org or by text to 406-646-9261. 

Additional Information:

Both organizations will host “Protecting the Big Hole,” a public event on Monday, July 14, at the Lewis & Clark Library in Helena. Doors open at 5:30 PM, and a livestream option will also be available. The evening will feature renowned aquatic ecologist Dr. Kyle Flynn, who will present two years of water quality data collected by Save Wild Trout. Brian Wheeler will also provide updates from the field and discuss Save Wild Trout’s expanded monitoring and advocacy efforts across the Jefferson Basin. Sign up here to join online.

This spring, Save Wild Trout and the Big Hole River Foundation formally merged their science and monitoring efforts to provide critical, independent, science-based monitoring across all four rivers of the Jefferson Basin: the Big Hole, Beaverhead, Ruby, and Jefferson. While new to Save Wild Trout, Brian Wheeler has led this work for years as Executive Director of the Big Hole River Foundation (BHRF), bringing deep experience, strong community ties, and a commitment to science-driven river protection. BHRF’s studies of nutrient levels and aquatic invertebrates—bugs—are the most extensive ever conducted for the Big Hole and its tributaries. This expanded program now builds on that foundation using field observation, data loggers, and lab analysis to track key indicators of river health, including water temperature, dissolved oxygen, nutrient loading, and turbidity.

“Over the past six years, BHRF has built one of the most respected citizen-science water quality monitoring programs in Montana. We’ve identified excess nutrients as one of the primary threats to the Big Hole, delivered actionable data to state agencies, and helped lay the groundwork for meaningful, science-driven restoration on the mainstem river,” said BHRF Chair Sarah J. Ashworth in announcement to supporters, ”Now, our small, standalone organization has the opportunity to scale this work up to the entire Jefferson Basin and meet the growing challenges our Southwest Montana rivers face - nutrient pollution, dissolved oxygen depletion, rising water temperatures, and depleted water resources - by growing the program under the umbrella of SWT.” 

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Big Hole River Foundation Joins Forces with Save Wild Trout; Save Wild Trout Welcomes New Full-Time Program Director