Zebra and Quagga Mussels
Dreissena polymorpha and Dreissena rostriformis bugensi
Vectors of spread:
Size: Adult mussels are very small, up to 3 cm. Recently settled mussels are only a few millimetres long and feel like sandpaper. Larval forms are free swimming and are not visible to the naked eye.
Colour: Brown and cream colour. Often have zebra stripes, but they are not always present.
Shape: Propeller blade or “D” shaped.
Habitat and Origin
Origin: Both Zebra and Quagga Mussels originate from Europe. They are fresh water bivalves native to the Black Sea region. Zebra and Quagga Mussels were introduced to North America through the ballast water of trans-continental ships in the late 1980’s.
Habitat: Lakes, rivers, shorelines, submerged hard surfaces.
Zebra and Quagga Mussels reach maturity after 1-2 year. A mature female can produce one million eggs per season, and reproduction starts when the water temperature reaches 12 degrees Celcius or warmer. Zebra and Quagga Mussels have a life span of roughly 2-5 years.
Vectors of Spread
- Invasive mussels are easily dispersed in their juvenile stages while they are tiny, free swimming larvae that cannot be seen by the naked eye. Any amount of water in or on a boat can contain this larvae. The larvae settle onto surfaces such as the hull of a boat or fishing gear, and slowly grow into adult mussels.
- Newly settled mussels are also difficult to detect as they are only a few mm’s across.
- Adult mussels can live out of the water for up to 30 days. Moving a boat, canoe, kayak, SUP, or fishing gear between water bodies can transport both the larvae and the adult mussel forms.
Economic and Ecological Impacts
- One mussel can filter up to 1 litre of water a day! Zebra and Quagga Mussels filter out nutrients and micro-organisms such as plankton which are the base of the food chain for BC’s native aquatic species. This could result in the collapse of valuable native fish populations in BC such as sockeye salmon.
- Zebra and Quagga Mussels also lead to increased growth of aquatic weeds along lake shorelines which degrades water quality and the aquatic environment.
- Invasive mussels overgrow and clog water intake pipes of power stations, municipal water supplies, and agricultural water intakes. They coat beaches, docks, and the propeller and hulls of boats to the point that they become unusable.
- In BC, it is estimated that they would cause $43 million damage per year to hydropower, agriculture irrigation, municipal water supplies, and recreational boating, once established. Economic losses to fisheries,tourism, and property values are not included in this number.
What Can I Do?
Zebra and Quagga Mussels have not yet been reported in BC, so PREVENTION is key!
Clean, drain, and dry your boat, trailer and other equipment before moving it to a new water body. This prevents the transport of invasive mussel adults or larvae between lakes and rivers.
- Clean: Remove plant fragments, aquatic species, and mud from any watercraft or equipment (boots, waders, fishing gear). If available, use a power wash station.
- Drain: Drain all items that can hold water onto land (e.g. buckets, bait water, wells, ballast, and bilge).
- Dry: Make sure all items are completely dry before entering a new water body.
- BC Ministry of Environment, BC Invasive Mussel Defence Program, https://www2.gov.bc.ca/gov/content/invasive-mussels
- Invasive Species Council of British Columbia, Zebra and Quagga Mussels, https://bcinvasives.ca/invasive-species/identify/invasive-animals/zebra-and-quagga-mussels
- Ontario’s Invading Species Awareness Program, Zebra and Quagga Mussels, http://www.invadingspecies.com/zebra-quagga-mussels/
- Sea to Sky Invasive Species Council, Zebra and Quagga Mussels Factsheet, https://ssisc.ca/wp-content/uploads/2018/07/Factsheet_Invasive-Mussels-2017-08-24.pdf