30-day dry time proposed for Yellowstone-bound boats

Billings Gazette

BILLINGS – To reduce the possibility of invasive mussels reaching Yellowstone Lake, the National Park Service is considering a requirement that a boat be inspected and sealed to its trailer for 30 days ahead of its intended launch date.

The requirement, if adopted, would apply to all inboard/outboard and inboard jet motorboats and sailboats. The Park Service referred to such craft as complex motorized boats. An exception would apply to boats powered only by an outboard motor.

“Large, complex, trailered watercraft pose the highest risk of transporting and introducing invasive mussels, and other AIS, because they are difficult to inspect and less likely to completely drain/dry or be fully decontaminated,” the Park Service wrote. “Manual decontamination with the use of hot water is not always 100% effective in removing all mussels. Given this, a 30-day dry time is needed to mitigate the risk associated with these watercraft.”

In addition, the Park Service is proposing to “deny launch to any watercraft (motorized or non-motorized) that has previously been fouled by mussels, regardless of dry time.”

In seeking public comment through April 5 on the proposal, the Park Service cited the “increased risk of invasion” by zebra and quagga mussels, collectively referred to as dreissenid mussels, “following recent detections of these highly invasive species in waterways” close to the park.

The mussels “have caused irreversible ecological damage and extensive impacts to infrastructure and recreation in waterways throughout the Midwestern and Eastern United States, as well as in the lower Colorado River Basin,” the Park Service noted.

New infestations were detected in South Dakota’s Pactola Reservoir in 2022 and the Snake River near Twin Falls, Idaho, in 2023. The Idaho detection was the first time the mussels had made it into the Columbia River Basin.

In addition, during inspections last year and in 2022, Yellowstone officials “intercepted and denied launch to mussel-fouled watercraft, highlighting the urgency and severity of the threat.”

“Given Yellowstone National Park is located at the headwaters of the Yellowstone, Snake and Missouri river drainages, pro-active measures are required to ensure the long-term ecological integrity not just of Park waters, but also of downstream mussel-free waters in Wyoming, Montana and Idaho,” the Park Service wrote. “Failure to prevent invasion by dreissenid mussels could result in widespread negative impacts to natural resources and recreational values, and could undo over two decades of work to restore populations of native Yellowstone cutthroat trout (Oncorhynchus virginalis bouvieri) within the Park. Because there are no effective eradication methods, and control/containment is both costly and environmentally consequential, prevention of an introduction is critical.”

Seals from Yellowstone National Park; Idaho State Department of Agriculture; Montana Fish, Wildlife, and Parks; and Wyoming Game & Fish Department will be honored pending verification of the 30-day dry time during a mandatory Yellowstone AIS inspection prior to launch. Boaters will also be asked to present the inspection receipt from the date the seal was applied.

The preferred method for submitting comments is online at parkplanning.nps.gov/yellboats. Comments may also be mailed to: Yellowstone Center for Resources Attn: AIS Proposed Changes, PO Box 168, Yellowstone National Park, WY 82190. The deadline to submit comments is April 5.

At the conclusion of the 30-day public comment period, the NPS will analyze and consider all comments received.

A final decision is expected this spring.