Canada Water Week: Searching for the Elusive Caddisfly

It’s Canada Water Week – and today we celebrate water hero Heather Leschied, program manager for Living Lakes Canada. Heather leads a Loblaw Water Fund supported project in the British Columbia’s Flathead River. She does it for the fascinating creatures that live below the water’s surface like the elusive caddisfly, one of the animals without backbones – ‘benthic invertebrates’— that can tell her a lot about river health.

Heather Leschied has always felt drawn to fresh water. Some of her earliest memories are being tucked into her mother’s chest waders as she fished in the streams around Lake Huron. She remembers, even at an early age, being captivated by the creatures that lived in the water, and spending many hours searching under the rocks for crayfish with her father.
Heather now spends her days knee deep in the clear blue waters of B.C.’s Flathead River, studying aquatic insects, worms and snails. These ‘benthic invertebrates’ tell her a lot about the condition of the watershed. Living Lakes is conducting water quality monitoring in five river basins here, helping efforts to establish a conservation area for the Flathead Valley in southeastern British Columbia.

The Flathead River is a tributary of the Columbia River that flows from its headwaters in southeastern British Columbia through Montana, where it joins the Pend Oreille River, and then through Washington State to the Pacific Ocean. Its valley is a key corridor for animals like the grizzly bear, passing through from Montana’s Glacier National Park to Canada’s Rocky Mountains.
It’s also home to the caddisfly – a moth-like aquatic insect that makes its homes from twigs hidden in the rocks of stream beds. At the larvae stage, caddisflies cover themselves in stones and sand, creating a bejeweled coat of many colours. As adults they produce a sticky silk that allows them to build an amazing array of ‘houses’ that offer protection and camouflage in freshwater currents.

Caddisflies are good indicators of river health. Most species have a low tolerance to water pollution, so a substantial caddisfly population indicates that the water is clean and has low levels of pollution. Finding caddisfly larvae indicates that the ecosystem is healthy and functioning, and also likely supports a diversity of other aquatic species as well. For this reason, they’re a favourite of fly fisherman. Trout feed on all stages of the caddisfly during its life cycle: larval, pupal, and adult stages. Therefore if a river supports a healthy caddisfly population then trout will likely be abundant as well.
By supporting this work, the Loblaw Water Fund is also helping support the formation of a community-driven stewardship group that is helping to monitor and protect the health of the Flathead River. Together, industry, local government and community members are working to protect one the most biologically important places on the continent. A place to be protected so that future generations may enjoy this wild place and water species may thrive.
During Canada Water Week, show your support for our rivers, lakes and streams. Join the hundreds of Canadians working across the country to protect water health. You, too, can become a Water Hero by making a donation to our Loblaw Water Fund projects.