Officials issue warning after finding harmful creatures in US waterways: 'We're getting more alarmed'

Aquatic invasive species have been popping up in the waterways of the United States for years, but a report has shown a worrying increase in their spread in one state.

What's happening?

Roughly a dozen new instances of invasive aquatic species have been cataloged in Montana by volunteers and biologists in 2025, according to the Daily Inter Lake. Some of the species spotted include the faucet snail, the fragrant water lily, and two additional types of snail, one from New Zealand and the other from Malaysia.

The biggest concern is the presence of zebra and quagga mussels. The outlet cited the United States Geological Survey, which observed that Montana is one of only 10 states with no known occurrences of either species, though there was a brief appearance in 2016. 

In 2025, the researchers found zebra and quagga mussels on 38 of 120,000 vessels inspected passing through Montana checkpoints, a figure lower than in the past but still concerning, according to officials. 

"They're getting closer and closer to here, and we're getting more alarmed the closer they get," said Tom Woolf, the Aquatic Invasive Species Bureau chief for Montana Fish, Wildlife and Parks, told the Western Montana Conservation Commission, per the Daily Inter Lake. "Our island is really shrinking here."

The threat posed by mussels is further complicated by differences in state regulations and prevention programs across surrounding areas. Woolf said improvements are planned to improve Montana's programs, but they are facing federal funding issues in the form of cuts or delays from several different agencies. 

Why are invasive species important?

Invasive species can wreak havoc on a region's biodiversity. In the case of zebra and quagga mussels, they filter plankton, depleting resources for native species, per the Invasive Species Center. They also clog water intakes thanks to their dense colonies, and pose a risk to swimmers, potentially cutting their feet.

While initially introduced to the Great Lakes, zebra mussels have continued to spread, threatening waterways across the country, including in the Des Moines River in Iowa. 

It's not just environmental issues that invasive species cause; they also cause economic ones. According to the U.S. Department of Agriculture, invasive species have cost the U.S. economy over $26 billion per year since 2010.

What's being done about the invasive species?

While Woolf noted the funding issues, he is still hopeful about engaging the community. This includes encouraging participation in boating inspections and urging people to report encounters and sightings to the Montana Natural Heritage Program via the iNaturalist app.

Elsewhere, states are cracking down on the spread as much as possible, such as Michigan, which introduced a bipartisan bill that would support a coordinated response to combat zebra mussels.

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