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Quagga and zebra mussels have spread rapidly across the country since they were first discovered in the late 1980s and, according to U.S. Army Corps of Engineers officials, have spread to every major river basin in the U.S. except the Columbia River Basin in the northwest. The mussels typically are spread by recreational watercraft such as boats, canoes, and Jet Skis that have been in infested waters. Once established in a water body, the mussel species are extremely difficult to eradicate because they have no natural predators in the U.S. and rapidly reproduce.

GAO was asked to examine efforts the Corps has undertaken to prevent the spread of aquatic invasive species into the Columbia River Basin by recreational watercrafts. This report [PDF, 3.24 MB] provides information on the Corps' Watercraft Inspection and Decontamination Program and its role in helping to prevent the introduction or spread of quagga and zebra mussels—the aquatic invasive species of greatest concern to the Corps—as well as program challenges and opportunities for improvement.

Colorado Parks and Wildlife (CPW) announces additional zebra mussel veligers found in the Colorado River and Government Highline Canal after increased testing. With these additional detections, both the Highline Government Canal and the Colorado River meet the criteria for being considered “positive” for zebra mussels.
See also: Colorado Parks and Wildlife announces discovery of zebra mussels in the Colorado River and the Government Highline Canal (July 16, 2024), nearly two years after the invasive species was first detected in the state. 

Officials at the U.S. Department of the Interior (DOI) announced in June 2017 that DOI would coordinate with the Western Governors' Association, states, tribes, federal agencies, and other partners in a project to help strengthen existing efforts to address invasive mussels. The actions described in the 2017 report, Safeguarding the West from Invasive Species, Actions to Strengthen Federal, State, and Tribal Coordination to Address Invasive Mussels [PDF, 1.3 MB], vary from policy and program reviews to on-the-ground efforts to prevent, contain, and control invasive mussels. One recommendation in Safeguarding the West was the development of a reference manual to facilitate rapid response activities in the event of mussel introductions in the Columbia River Basin. The U.S. Fish and Wildlife Service recently finalized and released this manual, Dreissenid Mussel Rapid Response in the Columbia River Basin: Recommended Practices to Facilitate Endangered Species Act Section 7 Compliance (Oct 2019) [PDF, 4.3 MB].

See also: Quagga and Zebra Mussels for more information

Zebra mussels are a small, destructive invasive species that can spread across Texas by hitching a ride on boats and trailers. Zebra mussels can cause tremendous environmental and economic damage - hurting aquatic life, damaging your boat, hindering water recreation and even threatening your water supply. In the state's ongoing effort to combat the spread of invasive zebra mussels, new rules effective July 1, 2014 require that all boats operating on public fresh water anywhere in Texas be drained after use.

Invasive zebra and quagga mussels are an immediate threat to Western states. With no controls, they spread rapidly, foul boats and equipment, clog water intake, and increase costs to hydropower operations and municipal water utilities. Even dead mussels can be a nuisance, littering beaches with shells. Management of these invaders is expensive; in the Great Lakes, managing mussels costs about $500 million annually. Until 2007, the mussels were limited to waterways and lakes east of the Mississippi, but now they have spread westward. In 2016, quagga mussels were found in Lake Powell.

Unfortunately, there are no foolproof existing technologies or treatments to eradicate established mussel populations in large, open water systems in an environmentally sound manner. Early warning, however, helps us prepare before the mussels or other invasive species arrive.

Invasive zebra and quagga mussels alter ecosystem dynamics and affect industrial, municipal, and recreational water users. The negative impacts of these dreissenid mussels drove scientists to search for effective control methods beginning in the early 1990s. Since then, researchers have uncovered various control methods, each with their own advantages and disadvantages. Both chemical and physical treatments have been developed and used by state and federal agencies in the control of zebra mussels.

The Invasive Mussel Collaborative announced today that it has released a new strategy to reduce invasive mussels and their negative impacts. The Strategy to Advance Management of Invasive Zebra and Quagga Mussels is intended to drive investments, policy, and research around invasive mussels across the Great Lakes region and beyond. Since their initial discovery in 1989, zebra and quagga mussels have had dramatic impacts on the Great Lakes ecosystem and economy, including changes to the food web, degrading fish habitat, interfering with drinking water systems and damaging tourism and recreation economies. Today, these mussels continue to spread to new water bodies across the U.S. and Canada.

On August 5, the Washington Department of Fish and Wildlife (WDFW) received notification from a local wholesale aquarium company in Renton of possible invasive freshwater mussels on a shipment of Marimo moss balls (Aegagropila linnaei). Moss balls are a commonly used decorative algae in aquariums and water gardens. Lab testing confirmed the mussels were zebra mussels (Dreisena polymorpha), a prohibited aquatic invasive species in Washington that, if established in local waters, would be capable of causing significant infrastructure and environmental damage. Zebra mussels and a close relative, the quagga mussel, are not known to be established in Washington.

Idaho watercraft inspectors have identified zebra mussels on a commercially hauled sailboat destined for Lake Coeur d’Alene in the state’s northern panhandle, marking the first time the invasive species has been found live this year.

On Sunday, June 27, watercraft inspection stations in eastern Montana intercepted two boats entering the state carrying invasive mussels, making it the 35th and 36th mussel-fouled boats intercepted this year. This surpasses the total number of 35 mussel-fouled boats intercepted in 2020.

Fish, Wildlife & Park staff reminds anyone transporting motorized or nonmotorized boats into Montana that an inspection is required before launching, and stopping at ALL open watercraft inspection stations is required. Failing to stop at an inspection station can result in a fine of up to $500. Many residents of western states, including Montana, are buying boats out of the Midwest or southwestern U.S., where invasive mussels are common. The record number of interceptions is a reminder for people purchasing boats from other states to clean, drain and dry the vessel.

Montana’s first mussel-fouled watercraft of the year was intercepted at the Anaconda watercraft inspection station on March 10.

All watercraft entering the state of Montana with the intent of being launched into any body of water are required to be inspected, including kayaks, canoes, rafts and paddleboards. These inspections are required by law, and failure to comply may result in a fine of up to $500. Learn more how Protect Montana Waters from Aquatic Invasive Species.

Provides detailed collection information as well as animated map.

Watercraft Inspection and Decontamination Programs - Many Western states instituted watercraft inspection and decontamination programs after the discovery of invasive mussels in Lake Mead in 2007. This section provides resources on mandated watercraft inspection and decontamination programs, as well as some non-mandated but state-funded watercraft inspection efforts.

Aquatic Invasive Species Decals - Some U.S. states require that boaters purchase an aquatic invasive species decal (sometimes called a stamp, sticker, or permit) before operating watercraft in that state. Many of these regulations were instituted as a response to the spread of zebra mussels and quagga mussels into the Western U.S. Fees from the purchase of these decals are typically used to fund local aquatic invasive species outreach and prevention activities.

Following the detection of invasive aquatic mussel larvae in Nov 2016, the State of Montana's Mussel Response Team was formed to rapidly assess the extent and severity of the mussel incident impacting Montana's waterways. Aquatic invasive species (AIS), including diseases, are easily spread from one water body to the other. To protect Montana’s waters and native aquatic species, please follow the rules and guidelines... clean, drain, dry.