Stop the Spread-Zebra Mussel

by | Nov 29, 2016 | News | 0 comments

Trout Unlimited Canada’s Stop the Spread campaign focuses on preventing the spread and impact of invasive species and pathogens that threaten Canada’s fisheries. There are a number of invasive species threatening Canada’s water. Meet the Zebra Mussel.


zebra mussel

Zebra mussels can be identified by their triangular-shaped convex shell that is black or brown with zigzagged bands ranging from white to yellow, although color patterns may vary. Its average size is 2 to 2.5 cm long but can reach up to 4 cm. They usually grow in clusters and are generally found in shallow (2 to 15 m) algae-rich waters.

Zebra mussels first arrived in Canada, through the Great Lakes, from ballast water discharged from ships, originating from the Black and Caspian seas region in southeastern Europe, which were contaminated with them.

Impact of Zebra Mussels on Our Environment

Zebra mussels feed on phytoplankton by filtering up to one liter of water per day, severely depleting phytoplankton communities and altering food webs of native aquatic life and aquatic ecosystems. In addition, selective feeding of this invasive species increases blooms of toxic algae. Large colonies of zebra mussels often kill native mussels, crayfish and snails by attaching themselves to these animals, hindering their movement, feeding and respiration.  Zebra mussel clusters can also suffocate fish spawning areas. Female zebra mussels can lay up to one million eggs each year. Easily dispersed, the microscopic larvae are scattered by water currents, wind and waves. Within a few weeks, their shell begins to develop and they can begin dispersing by attaching themselves to the hulls of boats.

Why Should We Care?

  • Zebra mussels cost taxpayers. In Ontario alone, the impact of zebra mussels is currently estimated to be about $75 to $91 million per year.  It is estimated that if there was a zebra mussel infestation in Alberta, for example, would result in $75 million in annual costs to remove them.
  • Like many other aquatic invasive species, it is nearly impossible to eradicate zebra mussels once established. Prevention is critical.
  • Zebra mussels destroy native fish populations, Within five years of an infestation of zebra mussels in the Great Lakes system, previously robust walleye populations were decimated.
  • Infested beaches and shallows are hazardous to walk as the zebra mussel’s sharp shells cut human skin.

How Can You Stop the Spread?

  • Become familiar with whirling disease and its impact on fisheries
  • Using the Clean, Drain, Dry philosophy, remove any mud, aquatic plants, other animals and debris from all equipment that entered the waterbody (e.g. boating, wading and fishing equipment) before leaving the waterbody. Dry for at least five days before visiting another waterbody.
  • Drain ballast tanks, portable bait containers, bilges, livewells and baitwells prior to leaving the waterbody. Keep drain plugs removed while transporting watercraft. Dry for at least five days before visiting another waterbody.
  • Dispose of all unwanted bait and fish waste in the garbage to ensure that zebra mussels, which may go unnoticed are properly disposed of.
  • Talk and inform others about the dangers of whirling disease and other aquatic invasives.
  • Support Trout Unlimited Canada’s Stop the Spread program.

Trout Unlimited Canada is a nonprofit, charitable organization. Donations are tax deductible as allowed by law.