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Proposal to Implement Certain Restrictions for Launch of Some Types of Motorized Boats to Reduce the Risk of Aquatic Invasive Species

Yellowstone National Park » Proposal to Implement Certain Restrictions for Launch of Some Types of Motorized Boats to Reduce the Risk of Aquatic Invasive Species » Document List

The National Park Service (NPS) is seeking public comments on Yellowstone National Park's (Park) proposal to implement a 30-day mandatory dry time for some types of motorized boats and sailboats before entering Park waters to prevent the spread of aquatic invasive species (AIS).

The Park is facing an increased risk of invasion by zebra mussels (Dreissena polymporpha) and quagga mussels (Dreissena rostriformis bugensis) following recent detections of these highly-invasive species in waterways within a day's drive of the Park. Dreissenid 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. With the discovery of new infestations in Pactola Reservoir, South Dakota (2022) and the Snake River near Twin Falls, Idaho (2023) - the first such detection of dreissenids in the Columbia River Basin - these invasive organisms are now present just hours from Park waters. In both 2022 and 2023, Yellowstone's AIS inspectors intercepted and denied launch to mussel-fouled watercraft, highlighting the urgency and severity of the threat.

To protect park waters and respond to this threat, the NPS is proposing a 30-day dry time requirement for complex, motorized boats (inboard, inboard/outboard, and inboard jet) and sailboats prior to launching in the Park. 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. 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 NPS is proposing to deny launch to any watercraft (motorized or non-motorized) that has previously been fouled by dreissenid mussels, regardless of dry time. The launch of watercraft that have previously been mussel-fouled threatens park resources and increases the chances of false dreissenid detection by routine environmental DNA monitoring of Park waters, which could result in significant impacts to Park operations and public recreational opportunities.

These requirements will enhance protections for aquatic resources in the Park and build on existing protections, including the prohibition on watercraft equipped with sealed internal ballast tanks (2019), as well as the prohibition of watercraft with evidence of live or dead mussels (2022).

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. 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.

To meet this new requirement, boaters will need to have their watercraft inspected and sealed to its trailer at least 30 days in advance of their intended launch date. 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 an already-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 comment period will be open for 30 days from March 7 to April 5, 2024.

Contact Information

Morgan E. Warthin
Chief of Public Affairs, Yellowstone National Park
307-344-2015
yell_public_affairs@nps.gov