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Coastal beavers are helping bring back salmon populations

Date: 16-Sep-19
Author: Doug Donnellan

Beavers build dams that slow down the current’s flow and leave pools of water behind, helping young salmon survive.

Beavers build dams that slow down the current’s flow and leave pools of water behind, helping young salmon survive.

In north-west Washington, USA, beavers are helping to create a better environment for Chinook salmon and giving them a much better chance of survival.

After the adult salmon swim upstream towards Olympic National Park and lay their eggs, the hatchlings rely on a slow-moving current to help them develop enough before heading out to sea. If the current is too strong, the young salmon can be pushed out prematurely and are then left vulnerable to predators. That’s where beavers, nature’s most effective hydrologic engineers, lend a hand.

In the river side channels, beavers build dams that slow down the current’s flow and leave pools of water behind. These pools can provide a place for fish to hide from predators, and even a sanctuary in times of drought. Slower moving water also makes insect larvae, the young salmon’s favourite food, easier to catch.

Greg Hood, a senior research scientist at Washington’s Skagit River System Cooperative said, “The pools beavers make are too shallow for diving predators like mergansers and kingfishers and bigger fish. But the pools are too deep for waders like great blue herons, and there’s too much shrub around the margins, so birds with big wings can’t get in there.”

The slower speed also helps to retain more of the flowing nutrients and sediment in the river channels, which helps attract a wider diversity of wildlife in the ecosystem. Beavers are so effective at improving survival rates for some fish that environmental groups are even relocating beavers to help rebound populations.

Anne Shaffer, lead scientist and executive director for the non-profit Coastal Watershed Institute said, “All we have to do is get out of their way and these coastal engineers will work their magic.”

 

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Positive Environment News has been compiled using publicly available information. Planet Ark does not take responsibility for the accuracy of the original information and encourages readers to check the references before using this information for their own purposes.

 




Doug                                              Donnellan
Author: Doug Donnellan

Doug joined Planet Ark's Information Centre team in April 2019 after completing a Master's of Sustainability. As a professional chef with his own catering business, Doug possesses a strong interest in food sustainability.



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