Aquatic invasive species

Protecting waterways from aquatic invasive species

If you live in Edmonton, you may have a stormwater pond in your neighbourhood. These ponds help prevent flooding by collecting and managing water from heavy rain and melting snow. They also help improve the quality of this water before it eventually returns to local creeks and the North Saskatchewan River.

Aquatic invasive species pose a risk to local waterways and the river. There are different kinds of fish species that are invasive, including certain kinds of carp and goldfish. These invasive fish can overwhelm native fish populations and harm the ecosystem. It’s important to prevent them from reaching these waterways. One way we do this is by managing and removing them if they are found in stormwater ponds.

How we manage aquatic invasive species in stormwater ponds

EPCOR routinely monitors the stormwater ponds we own and operate. If we find invasive species, we take steps to remove them. We are committed to protecting the environment and required by our regulator Alberta Environment and Protected Areas to manage the presence of invasive species in Edmonton’s stormwater ponds.

We remove them in the most effective and efficient way possible, by treating the pond with a naturally occurring, organic compound called rotenone. When applied as prescribed on the label, this treatment only affects fish and other gilled species and breaks down naturally in water with no long-term adverse effects. It's used in many municipalities around Alberta and in the national parks and is approved for use by Health Canada.

Invasive fish removed from Keswick stormwater pond in 2021.

You can help - don’t release invasive fish into stormwater ponds

Invasive fish can grow big in a natural environment - much bigger than when they are in an aquarium. They also reproduce a lot, which means they can take over and harm native fish populations. All Edmontonians can help protect our local water bodies by not releasing fish (alive or not) into stormwater ponds or other bodies of water. Even fish that are no longer living may contain eggs that can still hatch.

If you have one of these fish that you can no longer keep, you can:

Ask a local pet store for advice or see if you can return or surrender it.
Give it to another aquarium owner who can take care of it.
Donate it to a local aquarium society or school.
Talk to your veterinarian about humane ways to dispose of it.

To protect our local waterways, it's important to keep these fish as pets and not release them.

Resources

Government of Alberta

Government of Canada

About aquatic invasive species

Frequently asked questions

Aquatic invasive species can cause problems for native fish and the local ecosystem. They compete for food and space and even eat their eggs. They are really adaptable and can live in tough conditions, so they can quickly take over and outnumber native fish.

Using rotenone, a plant-based, naturally occurring chemical compound, to treat stormwater ponds is a standard practice that has been successfully used in other Alberta communities and national parks. It helps us remove aquatic invasive species from our stormwater ponds in the least disruptive and most effective way, and it is approved by Health Canada for this purpose. To be effective, two treatments of rotenone may be required, between three to six weeks apart from one another. Other methods, like draining the facility and scraping the bottom, have been attempted but were found to be more costly, disruptive and does not deliver the same effective results.

Aquatic invasive species are a risk to all local waterways. There are no bodies of water where they can be safely released into the natural environment.

When applied as prescribed on the label, this treatment only affects fish and other gilled species and breaks down naturally in water with no long-term adverse effects. All animals have natural enzymes in their digestive tracts that neutralize rotenone, except for gill-breathing species who do not have these enzymes. Therefore, if other animals drink the water or eat the fish, they won't be harmed because their digestive systems neutralize any leftover rotenone.

If you live adjacent to a stormwater pond that will be treated, you will receive notification three weeks before this work begins. One week before treatment, we will place signs and temporary fencing around the stormwater pond. We may also need to temporarily close some portions of trail near the pond. Prior to the treatment, the water levels in the facility will be lowered. On the day of, our contractor will be onsite working safely to apply the treatment, after which the invasive fish will be collected. Typically, within the next 48 hours, we will remove the fencing and reopen any sections of trail that were closed.

Like Edmonton, many communities in Alberta and North America need to manage and mitigate the impacts of aquatic invasive fish by removing them from stormwater ponds. Rotenone is used across Alberta and North America, and Health Canada approved using rotenone for this purpose.