A certain species of fish was recently caught just outside the north entrance of Yellowstone National Park, and officials with Montana Fish, Wildlife, and Parks are concerned.

An angler reportedly caught a smallmouth bass on February 19 on the Gardner River at its confluence with the Yellowstone River. Smallmouth bass are not native to the upper Yellowstone River, and wildlife officials are worried that their presence may impact and pose threats to populations of fish that are native to the region.

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Montana Fish, Wildlife, and Parks
Montana Fish, Wildlife, and Parks
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FWP officials say that as of now, it's unclear how the smallmouth bass arrived in the upper Yellowstone and reminded anglers that it's illegal for people to move live fish from one waterbody to another without prior authorization from Montana FWP.

This isn't the first time that an angler has reported catching smallmouth bass on the upper Yellowstone River. There have been two reported cases in the past seven years. According to Montana FWP, two smallmouth bass were caught at the Highway 89 bridge just east of Livingston, and one near Emigrant. One smallmouth bass has also been found in the Shields River, a tributary to the Yellowstone east of Livingston.

However, FWP fisheries staff have not found smallmouth bass during yearly sampling efforts in the upper Yellowstone River.

One of FWP’s primary management goals in this area is to protect native Yellowstone cutthroat trout, which spawn in the tributaries and upper reaches of the Yellowstone River. An established population of invasive smallmouth bass could occupy the same areas, preying on and displacing trout and other native fish.

said Montana Fish, Wildlife, and Parks.

Anglers are important when it comes to managing smallmouth bass where needed. FWP staff are preparing a proposed emergency rule for the Fish and Wildlife Commission to consider, which could require anglers to kill and report any smallmouth bass caught in the upper Yellowstone River.

Until any proposed rules can be implemented, anglers are asked to voluntarily kill, remove and document any smallmouth bass caught in the Yellowstone River and its tributaries between the Springdale Fishing Access Site east of Livingston upstream to the Yellowstone National Park boundary and provide them to FWP for testing.