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Moving around rocks dangerous for fish habitat, warns Alouette River Management Society

Maple Ridge organization urges visitors to be mindful of riverbeds

Alouette River Management Society (ARMS) is urging the community to be respectful of waterbeds while they cool off in the river this summer.

Several rivers, lakes, and trails all over the world have people re-arranging the rocks, stacking them into what’s called cairns, or reshaping the way water flows by moving around the rocks. When people move rocks in the rivers, it creates small pools allowing people to dip in and relax. ARMS’ Alexandra Holmes expressed that while ARMS understood the need for people wanting to create pools in the river, if those are not restored before people leave, it could have detrimental effects on the health of the riverbeds.

“The Alouette has seen this frequently over the years as people come out to enjoy the river in the summer months. However, we have seen an increase with the extreme heat and the restrictions for travelling within the province,” she said, adding that with such extreme changes to the riverbed, it alters the river’s flow and can impact the sockeye, who are already sensitive to the changes in the river.

The Alouette River saw a late return of sockeye this year, but are hopeful more will come their way provided their environment isn’t disturbed.

“The creation of pools in the river, if the water stops flowing, can heat the water up to bath temperatures, which is great for hanging in the river, but deadly for any salmonid species. Water temperatures become stressful at 20 C and deadly for some salmonid species at 24 C. Altering riverbeds can take away their safe, cool areas that allow them to hide from the heat, especially during a heatwave like we are in now,” said Holmes.

These pools can also inhibit the passage of the salmonids up the river to their spawning grounds especially if the salmon become trapped and exhausted in these pools.

RELATED: Sockeye salmon return to fish fence in Maple Ridge for the season

“We are already seeing low numbers of return this year, believed due to the extreme heat and lack of precipitation. We want to attempt not putting any more stress on the salmon as they return up the river,” she added.

While moving rocks and disturbing the waterbed is dangerous for the salmon species, it is also prohibited to disturb, alter, or destroy fish habitat (HADD) under the Fisheries Act.

As per the Fisheries Act, disturbing the riverbed drastically by moving the river rocks can kick up sediment and impact the health of the salmon, and moving large amounts of river rock alters the landscape for the salmon to maneuver and can inhibit their ability to migrate to their spawning grounds, explained Holmes.

Holmes also said that it is important to pack out what we pack in.

“It is wonderful that the Alouette Watershed is being used frequently, however we want to leave it as we find it. You see a lot of garbage along the riverbank from tubers and rivers users, where it has just slipped away from them, so paying attention to your items is really important. The best thing is to enjoy the river as you found it and not altering it to begin with. Bring a chair down or tying up a tube to the bank or a tree, using shallow areas that are shaded, are great ways to enjoy the river without impacting it so severely,” said Holmes.

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Priyanka Ketkar

About the Author: Priyanka Ketkar

Priyanka Ketkar has been a journalist since 2011 with extensive experience in community-driven news writing, feature writing, and editing.
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