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Invasive mussels

Quagga and zebra mussels are invasive species that have major potential to cause harm to Alberta’s environment and economy if introduced.

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Aquatic invasive species

Place of origin

Quagga and zebra mussels originate from the Caspian and Black Sea regions in Eastern Europe. In 1986, zebra mussels were first discovered in Lake St. Clair (the Great Lakes). In 1989, quagga mussels were first discovered near Lake Erie. They were introduced through the discharge of ballast water from ships.

Since then, invasive mussels have spread throughout the Great Lakes and many lakes in Ontario, Manitoba and the United States. Overland watercraft transport has been the main pathway of spread across Canada and the United States.

To our knowledge, zebra or quagga mussels are currently not established in Alberta. For a map of confirmed locations, visit:

Identifying quagga and zebra mussels

Quagga and zebra mussels, which pose a significant threat to Alberta's aquatic ecosystems and economy, can be identified through key characteristics.

Quagga mussel (Dreissena rostriformis bugensis)

Quagga Mussel
  • 1 to 5 cm, D-shaped shell
  • Brown and yellow-white in colour, may have faint banding pattern
  • Native to Ukraine, now found in various parts of North America, such as in the Colorado River system – a popular destination for Alberta snowbirds
  • Live up to 5 years
  • More adaptable than zebra mussels – can attach to softer substrates and survive in colder water.

Zebra mussel (Dreissena polymorpha)

Zebra Mussel
  • 1 to 3 cm, triangular-shaped shell
  • Brown and yellow-white in colour, usually with light-dark banding or zigzag pattern
  • Native to Russia, now found in various parts of North America, such as in Lake Winnipeg and elsewhere in Manitoba. 

Invasive Species Hotline

Do you think you've spotted a quagga or zebra mussel? Remember, an attached mussel is an invasive mussel, native mussels will be buried in the sand.

Report it to Alberta's Invasive Species Hotline at 1-855-336-BOAT (2628).

Similar species

Image of size comparison featuring small invasive quagga and zebra mussels next to Alberta's native mussels, which are much larger on average.

Caption 1: Alberta’s native mussels (bottom row) are larger (adults often over 7cm in length) and have an elongated oval shape. They are free-living and can be found buried or partially buried in the bottom of lakes and slow flowing rivers. In contrast, invasive mussels (top rows) are small, angular or D-shaped and attach themselves to substrates.

Image comparing the appearance of fingernail clams as opposed to invasive mussels.

Caption 2: Fingernail (also called pill and pea) clams are small free-living native clams (pictured on the left). Though some are similar in size to invasive mussels, native clams are more rounded and symmetrical than invasive mussels and have thin, often transparent shells that are easily crushed.

Impacts of invasive mussels

  • Environmental impacts

    Invasive mussels are filter feeders that strain suspended matter and food particles out of the water. Excessive feeding by large invasive mussel populations disrupt natural food chains. This results in a depleted fishery (fewer and smaller fish) as the fish don't have enough food.

  • Impacts to infrastructure, recreation and economy

    Invasive mussels attach to hard substrates in the water, blanketing any surface and reproducing at extremely fast rates. Females can produce up to one million eggs every year, and there is no natural predator in Alberta. 

    Dense clusters of mussels clog water pipes and other submerged equipment, causing costly damage. Shells are sharp and can cause injury, impacting recreation when dead shells wash up on shore.

    Quagga and zebra mussels move from lake to lake by attaching themselves to boats and other recreational equipment. The adults can survive for 30 days out of water under ideal conditions, while the microscopic veligers (larval stage) can survive in standing water for long periods of time. 

    Currently, invasive mussels are found in eastern Canada and various parts of North America. If a mussel infestation occurred in Alberta, the province is estimating a total cost of $75,000,000 annually to protect and replace water operated infrastructure (such as drinking water systems, power generation and irrigation), and in lost revenue from recreational fishing. This estimate includes decreasing property values and increased boat maintenance costs for the individual Albertan.
     

Video: Impacts of Zebra Mussels

Take action

Clean, drain and dry your gear

If you are transferring a watercraft or equipment used in water (that is, hip waders, life jackets, kayaks, construction equipment, etcetera) between waterbodies, make sure to practice  clean, drain and dry efforts between uses.

Visit the pages below to find information boaters need to follow to help stop the spread of AIS:

Get the facts on how to clean, drain and dry your type of boat:

Don’t Let It Loose

Moss balls, also known as marimo balls, are popular aquarium plants that have been found in the past to be contaminated with invasive mussels. Avoid introducing invasive species by never releasing aquarium contents, live bait, live food, or other organisms into waterbodies.

Zebra and quagga mussels are prohibited species in Alberta under the federal Fisheries Act and Fisheries (Alberta) Act. Never import, own, sell or transport these species in Alberta. For more information, visit:

Invasive mussel decontamination protocol for retailers

Additional resources

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