New mussel added to list of Montana’s invasive species

HELENA – Golden mussels were recently added to Montana’s invasive species list. This listing prohibits the possession and transport of golden mussels in the state.

Golden mussels originate from Eastern Asia and were first identified in North America in Stockton, Calif., in October 2024. Their distribution now extends from Rio Vista to San Diego, Calif. Recently, the first golden mussel-infested boat seen outside of California was intercepted by the state of Oregon.

“This illustrates the new threat of this species expanding rapidly throughout California,” said FWP Aquatic Invasive Species Bureau Chief Tom Woolf. “It’s more important than ever to ensure watercraft are inspected when they enter the state and all boats are cleaned, drained and dry when they leave the water.”

Golden mussels are similar to zebra and quagga mussels and are transported on watercraft. Aquatic invasive species cause serious damage to Montana’s natural resources, economy and recreational opportunities. AIS can create significant, long-term ecological harm that can impact everyday life for current and future generations.

Mussels filter plankton out of the water, which are a vital part of the food chain that our native fish eat, thus causing. When they attach to boat motors and hulls, they reduce the performance and efficiency of the boat. They form dense colonies that clog water intakes, forcing power plants, utilities and irrigators to use costly control methods to maintain their systems.

All boaters and other water recreationists need to follow the rules to prevent aquatic invasive species from affecting Montana’s waters.

Those rules include:

• All boats must stop at all open watercraft inspection stations they encounter. Failure to do so could result in a fine of up to $500.
• Always be sure to clean, drain and dry your boat.
• All watercraft entering Montana are required to be inspected for aquatic invasive species. An inspection is required before launching on Montana waters.
• Nonresidents transporting watercraft into Montana must purchase a Vessel AIS Prevention Pass before launching. The fee is $30 for motorized and $10 for nonmotorized watercraft. The pass is valid until Dec. 31.
• Inspection is required for Montana residents before launch IF: the boat is entering the state, crossing west over the Continental Divide or entering the Flathead basin.