New detections of invasive Zebra Mussels in New Brunswick (DFO Press Release)

The zebra mussel that was found on a floating dock in Mactaquac in December 2024. Photo: DFO

In December 2024, during an inspection operation of floating docks in New Brunswick (NB), Fisheries and Oceans Canada (DFO) discovered the presence of adult Zebra Mussels in Mactaquac, near Fredericton, in the Wolastoq (Saint John) River. This is the first sighting of the invasive freshwater mussel in the main branch of the Wolastoq (Saint John) River and in the southwest region of the province. Zebra Mussels have already had a severe environmental and economic impact in other parts of Canada, including within the Great Lakes. 

To prevent the introduction of Zebra Mussels into new freshwater bodies and to stop their spread in New Brunswick, DFO and its partners are asking recreational boaters to be extra vigilant while on the Wolastoq (Saint John) River, and to ensure that they properly clean, drain, dry and decontaminate their boats and any nautical equipment before using them in another body of water. If someone thinks they have found an aquatic invasive species, like a Zebra Mussel, they should contact DFO to report it.

Reports can also be made to the New Brunswick Invasive Species Council by email at report@nbinvasives.ca or on our reporting page (this additional information is provided by NBISC).

Workshops will be held in New Brunswick and in Quebec in March 2025 to enable DFO, its partners and stakeholders to mobilize and coordinate their collective prevention, education and awareness efforts to help stop the spread of Zebra Mussels.   

Background information on the spread of Zebra Mussels in the Wolastoq (Saint John) River watershed since its detection in 2022

NBISC staff member Clarissa conducting eDNA sampling to look for traces of zebra mussel EDNA.

In 2022, the first detection of Zebra Mussels in the Wolastoq (Saint John) River watershed was confirmed at Lake Temiscouata in Quebec. Since then, DFO and its provincial, municipal, non-governmental, and Indigenous partners have been closely monitoring freshwater lakes and rivers in the province of NB to be able to detect and prevent any new presence of the aquatic invasive species as quickly as possible.  

In the summer of 2023, Zebra Mussels were observed for the first time in the province of NB in Edmundston, along a hydroelectric dam. In 2024, other Zebra Mussels were observed on the dam, as well as on the wharf of the Edmundston marina. These infrastructures are located on the Madawaska River about 40 kilometers downstream of Lake Temiscouata. In addition, in August 2024, Zebra Mussel larvae were observed in samples collected from the Madawaska River in Edmundston and from the Wolastoq (Saint John) River in Grand Falls, Beechwood, Nackawic and Mactaquac, NB. Although Zebra Mussels are spreading in the main branch of the Wolastoq (Saint John) River, monitoring efforts by DFO and its partners in several other bodies of water in NB have not yet detected its presence outside the Wolastoq (Saint John) River.  

The unwanted zebra mussel

Zebra mussels can grow up to 4cm in size (approx. the size of the end of your thumb) and have a distinct brown and beige/white “zig-zag” pattern. Photo: Dave Britton, US Fish and Wildlife Service.

Zebra Mussels are native to the Black Sea and Caspian Sea region of southeastern Europe. They were first seen in North America in the Great Lakes in the late 1980s. They arrived through ballast water discharged from ships. Since then, they have spread throughout much of eastern Canada and the United States.   

Zebra Mussels can spread quickly. Their larvae are microscopic, float in the water and follow the currents of lakes and rivers until they settle on a solid surface. They can even become reproducing adults within a short span of only three months in ideal conditions. Larvae can be transported unknowingly, from one body of water to another by residual water or by attaching themselves to ships, boats and other watercraft, as well as to nautical and fishing equipment, such as floating docks.  

Once established, Zebra Mussels can have negative impacts on freshwater habitats. They are particularly harmful to native mussels, many of which are species at risk, by monopolizing their food, such as plankton, and by suffocating them.  

Every year, Zebra Mussels cause millions of dollars in damage in Canada by clogging the intake structures of power plants and water treatment plants, in addition to damaging boats.  

Click here to learn more about identifying zebra mussels (this additional information is provided by NBISC).

Preventing the spread

A past NBISC staff member showing how to clean off a boat using hot water from a mobile boat wash station.

The new observations of Zebra Mussels made in NB remind us of the importance of preventing the spread of aquatic invasive species. DFO is working with the provinces of New Brunswick and Quebec, as well as the Organisme de bassin versant du fleuve Saint-Jean, the New Brunswick Invasive Species Council, the Northwest Regional Service Commission, the Société d'aménagement de la rivière Madawaska, and other local partners to educate and inform the public about the importance of adopting good practices as recreational boaters.  

Click here to learn more about these collaborative efforts (this additional information is provided by NBISC)

To learn more about the "Clean, Drain, Dry and Decontaminate" awareness campaign, please visit our webpage: https://www.dfo-mpo.gc.ca/species-especes/ais-eae/prevention/clean-drain-dry-decontaminate-lavez-videz-sechez-decontaminez-eng.html  

For media requests please contact: MediaGLF-GLFMedias@dfo-mpo.gc.ca.