From wetlands to walleye: How water quality shapes fishing success

Eutrophication is a widespread problem across the Prairies and the Great Lakes, Badiou says, and it’s one that’s becoming worse as watersheds release more nutrients as it gets warmer. As algal blooms die, microorganisms break them down. This decomposition process consumes oxygen and can release greenhouse gases.

“And so you get additional greenhouse gasses entering the atmosphere and that further contributes to climate change, so you get into a negative feedback cycle,” Badiou says.

Wetlands: Nature’s filter

This is where the power of wetlands comes in. Intact wetlands act like a big sponge, catching and filtering nutrients before they reach open water.

On the flip side, Badiou adds, research has shown that draining wetlands creates “phosphorus export hotspots.” Wetlands store phosphorus in their soils. When you drain them, that phosphorus can be released and move downstream into lakes and rivers.

Wetlands, Badiou adds, are also effective at trapping sediments and reducing turbidity (cloudiness or haziness) in the water column—something that’s important for fish, especially visual predators, he says.

“If you have lots of sediment and turbid water, the fishing may not be so great,” he says. There’s also repercussions for the spawning of some fish species.

Click here to learn more about how wetlands improve fishing.

“For example, walleye, which is one of the most important fish species recreationally, are pretty sensitive to sedimentation on their spawning grounds. Excess sediment can fill the spaces between rocks where eggs are laid, reducing the oxygen available to developing eggs,” Badiou adds. This makes clear water, and wetlands that filter sediment and nutrients, critical to healthy fish populations.

While anglers are most likely to notice algal blooms when the warm weather hits, some species of blue-green algae bloom under ice and can be problematic, Badiou says, but by and large, it’s a summer issue. However, degraded spawning grounds and a rough bloom season can mean fewer fish once anglers drop a line months later. Healthy watersheds upstream help keep fisheries resilient year-round.

Wetlands are fish habitat, too

Wetlands not only filter sediment and capture nutrients, they’re also productive fish habitat in their own right, filled with invertebrates to eat and vegetation that provides cover from predators—something that’s especially important for young fish and sustaining fish populations overall.

Even isolated Prairie wetlands that are disconnected hydrologically from lakes and rivers play an important role. 

“Many insects and other aquatic invertebrates begin life in these wetlands. Some emerge as flying adults that move across the landscape, while others reach nearby waterways during periods of flooding or high water. These insects and invertebrates become food for fish, helping support fish populations far beyond the wetland itself.”

Why wetlands matter for anglers

The takeaway is simple: clean and healthy water starts long before it reaches the lake. Safeguarding wetlands means fewer algal blooms, clearer water, healthier spawning grounds and stronger fish populations. 

Watch the video below to see wetlands at work.

By investing in wetland restoration and conservation, we can help keep Canada’s fisheries thriving for generations to come.

Click here to support Ducks Unlimited Canada’s work.