Have you ever been out fishing and seen the sign for “Stop Invasive Species” (usually around the boat launch area) or driving down the highway and seen the mandatory water craft inspection stations? Well this is for Dreissena Polymorpha or what we call the Zebra Mussel is a small freshwater mussel that was originally native to the lakes of southern Russia and the Ukraine. It has since accidentally been introduced into numerous other areas and has become an invasive species in many countries around the world.


Life Cycle of a Zebra Mussel 

The female releases eggs in the spring when water temperatures warm up to 12 degrees Celsius. Once the eggs become fertilized in water they become veligers (larval zebra mussels) which live in the water from late May through to October. Being microscopic (not to be seen with the naked eye) the veligers float in the water for 2-3 weeks making it extremely easy for them to be transported from one water body to another. After 2-3 weeks the veligers develop a shell and attach themselves to any firm surface. Zebra mussels generally live 2-5 years with a female producing up to a million eggs per year. No wonder these things are so invasive!


What Do They look Like?

Zebra Mussels are freshwater mussels that measure around 2.5 centimetres long but can grow up to 4 cm long. They are named after the dark striped pattern on their sharp shell.

Zebra Mussel

Zebra Mussel

How Do They Spread?

Zebra mussels can spread in many ways, they can be moved by boat, off road vehicles, water based aircraft and fishing equipment. The movement of water related equipment is the primary way this aquatic invasive specie moves from one water body to another.

Veligers (larval Zebra Mussels) are the most concerning stage. They can not be seen but can be transported in bait buckets, bilges or any other water source from invaded water to an un-invaded water body.

Adult zebra mussels can attach themselves to submerged items such as boat hulls, nets, docks etc. or pretty much anything that is left in the water. Once attached (and not removed) these guys can hitchhike on any of these items to a new water body.

Zebra Mussel

Zebra Mussel

What Do They Eat?

Zebra Mussels are filter feeders meaning they strain small particles of plant plankton from the water for food. Zebra Mussels consume so much plankton that there isn’t enough Zooplankton that young fish feed on and need to survive.

Fun fact- One Zebra Mussel can filter feed one litre of water per day.


What Impact Do They Have On Fish?

It has been found that Zebra Mussels interrupt the food chain which can negatively affect the growth and survival rate of the fish population.


Does Anything eat Zebra Mussels?

Zebra Mussels do not have many natural predators but it has been documented that several species of fish as well as diving ducks have been known to eat them.


What Problems Do They Cause?

* They negatively impact ecosystems.

* They filter out algae that other species need for food in order to survive.

* They have the ability to attach and incapacitate native Mussels.

* Power plants spend millions of dollars removing Zebra Mussels from clogged water intake systems.

* They have a negative impact on the fish populations.

* They can reproduce at an alarming rate.

* They have an economic impact of about $43 million dollars a year.

* They can survive weeks in only a moist environment.

* Are found in the Canadian Provinces of Quebec, Ontario and Manitoba along with 24 US States.

* These invasive mussels filter plankton (a food source of some native species.)

* Large colonies can take over fish spawning beds and beaches.

* They are becoming a water hazard as swimmers are reporting getting seriously hurt by them. Some have even needed stitches as the Mussel’s sharp shell can cause a deep gash.


How To Stop The Spread

* Wash your boat off with warm soapy water if possible.

* Do not transport water from live wells and bait buckets from one water body to another. Make sure you empty them onto land if possible and dispose the left over bait in the trash.

* Dry all items completely before using them in another body of water.

* For anyone living in BC (where we currently have not been invaded by them) it is mandatory to stop at the open inspection stations if you are transporting a boat, canoes, kayaks, paddle boards as well ass inflatable boats. Failure to stop could result in a $345 fine.

Invasive Species Inspection Sign

Invasive Species Inspection Sign



Make sure you clean your boat and related gear whenever you are moving from one water body to another as well as stopping at inspection points along the highway. By doing this you are protecting the waters that you love so much. I hope this information helps you or at least informs you of this invasive specie that is wreaking havoc in our much loved water.


What Are Zebra Mussels?

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