Spring and summer might feel far away for most of us, but boating season is right around the corner. And with the season, federal and state officials are looking to halt the march of harmful aquatic invasive species into the state.

Any watercraft transported into Wyoming must undergo a mandatory state inspection to look for aquatic invasive species in Wyoming waters. Yellowstone National Park announced Thursday it is considering a 30-day mandatory dry time for some types of motorized boats and sailboats before entering park waters and the prohibition of watercraft previously fouled by mussels regardless of dry time.

Officials are particularly worried about boats being brought in from the neighboring states of South Dakota, Nebraska and Utah, as each is listed as either a high risk state for harmful invasive species or have high risk waters within their borders. Wyoming faces new threats following recent detections at Pactola Reservoir, in South Dakota, and on the Snake River, in Twin Falls, Idaho. These waterways are within a day’s drive of northwest Wyoming.

Aquatic invasive species 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. 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.

Harmful impacts can occur to municipal water supplies, recreation, agriculture, aquaculture, and other commercial activities. Invasive species including amphibians, crustaceans, fish, plants and mollusks are present in Wyoming, most notably the New Zealand mudsnail and Asian clam. While these species cause problems and need to be controlled, the most significant known threat to Wyoming is from zebra and quagga mussels based on their proximity and demonstrated impacts in neighboring states.

“Wyoming is one of the few states left in the nation that hasn’t detected the invasive zebra or quagga mussels in our waters,” said Josh Leonard, AIS coordinator. “Game and Fish is dedicated to keeping these destructive invasive species out of our state’s waters. That’s why it’s crucial that out-of-state boaters and residents who have taken their boats out of Wyoming get their watercraft inspected before launching on any Wyoming waters.”

The best defense against AIS is vigilance by the public, according to Game and Fish. This month, the department will open AIS check stations across Wyoming. All boaters must stop when encountering an open AIS check station on their route of travel.

Any watercraft transported into Wyoming from March 1-Nov. 30 must undergo a mandatory inspection by an authorized inspector prior to launching on any Wyoming waterway, the department requires. However, if your watercraft was used on a water suspect or positive for invasive mussels in the last 30 days, it must be inspected prior to launching year-round and may require decontamination.

If boaters entering Wyoming do not encounter an open AIS check station on their route of travel, it is the boater’s responsibility to seek out an inspection before launching on any Wyoming waterway. 

Along with watercraft registration, watercraft used on Wyoming waters must have an AIS decal. A Wyoming AIS decal must be displayed on all watercraft (including rentals) using Wyoming waters with the exception of both soft and hard-sided stand-up paddle boards, amphibious vehicles propelled by wheels and non-motorized inflatable watercraft 10 feet in length or less. While these watercraft are not required to have a decal, they still require an inspection when coming from out of state.

The state requires that boats must stop at established check stations each time a boater passes a check station. Even if a watercraft has been previously inspected and has a valid seal and seal receipt, boaters are still required to stop at any open AIS check station. Having the properly affixed seal and valid seal receipt will expedite the inspection process, according to the department.

Inspections are also available at Game and Fish regional offices but you must call ahead. Inspection locations can be found at wgfd.wyo.gov/Fishing-and-Boating/Aquatic-Invasive-Species-Prevention/AIS-Inspection-Locations.

Yellowstone National Park

Yellowstone National Park is seeking public comment on proposed measures to help stop the spread of aquatic invasive species into park waters.

To protect park waters and respond to this threat, Yellowstone proposes a 30-day dry time requirement for complex, motorized boats (inboard, inboard/outboard and inboard jet) and sailboats prior to launching. 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. A 30-day dry time will mitigate the risk.

Watercraft (motorized or non-motorized) previously fouled by mussels, regardless of dry time, would be denied launch. The launch of fouled watercraft increases the chances of false mussel detection by routine environmental DNA monitoring of park waters. This could result in significant impacts to operations and public recreational opportunities.

These proposals would build on existing protections, including the 2019 prohibition on watercraft equipped with sealed internal ballast tanks, as well as the 2022 prohibition of watercraft with evidence of live or dead mussels.  

A 30-day comment period began March 7 and will be open for 30 days. 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 Friday, April 5.

At the conclusion of the 30-day public comment period, the Park Service will analyze and consider all comments received. A final decision is expected in spring 2024.