I tagged this article way back on April 7th and meant to write about it sooner but there was a beaver summit on the same day and you know what happens when you put things off. It’s good timing to revisit because you can never have too many articles about the slow and inevitable rise of the beaver IQ,

When Beaver met Salmon: how fish-friendly flow devices keep their relationship moving forward

WWF-Canada is working with partners to insert fish-friendly flow devices into beaver dams in Newfoundland and Labrador. But to find out how these devices work we need to learn more about beaver dams!

To the untrained eye, beaver activity — felling trees, digging channels and tunnels, building lodges and dams — can appear disruptive and downright messy, but through an ecological lens, they are creating complex (and crucial) habitats. This industrious process is why beaver have been awarded the title ecosystem engineer.

If you’ve ever visited a beaver pond, you might also notice that it’s surrounded by lush vegetation — a band of green that erupts behind the dam and around the pond’s edge habitat (known as the riparian zone). If you could see under water, you’d find an abundance of trout and young salmon. Beaver ponds are also a stopover spot for many species including rare and threatened songbirds. There are so many species that rely directly on beaver habitat for survival that they’re considered a keystone species, which means they are preforming a necessary role to uphold entire ecosystems.

Beavers have also co-evolved with local fish species across Canada (and globally throughout their range). Everywhere within their native range, beaver dams create complex environments used by fish. By increasing the large woody debris in streams and slowing the movement of water, beaver ponds are refuges for young fish such as salmon parr. The plant material and other debris captured in the pond also promotes insect abundance, so there’s plenty to eat in this stable, protective environment. This results in increased growth and survival, which consequently promotes population recovery for the fish.

Well this is shaping up to make a lot of sense! An article from the World Wildlife Fund that reminds people who fish need beavers!

It is a common practice for beaver dams to be removed. Sometimes this happens because a pond is causing a railway or farmland to be flooded. But sometimes beaver dams (and beavers themselves) are removed from ecosystems because they’re thought to be an impediment for salmon migrating in streams. While it is very rare to have complete blockage of fish passage for the span of the migratory period, salmon can be delayed for days or weeks due to inadequate water depth, which they need to propel themselves past the dam, or they may be reluctant to move through an area with reduced flow.

However, it’s the perception of this risk that leads to routine dam removals, and, unfortunately, general habitat degradation. When beaver dams are removed, the beaver pond/wetland is drained and young fish, which depend on the calm waters behind the dam, are flushed quickly downstream into fast-flowing water.

Ir’s always the PERCEPTION of risk that does beavers in. I just chatted yesterday with Rachel Siegel of Illinois who is doing a heckuva job raising beaver awareness there and she told me she had spoken with a big wig fish scientist in the area who expressed concern that beaver dams would BLOCK their migrating fish,

What migrating fish does Illinois have, you ask? Me too. None that go to the ocean that’s for sure. But some like to move up and down stream or from one body of water to the other. I reminded her that we used to have MILLIONS more beaver and MILLIONS more fish. So the species co evolved and get along just fine, thank you very much. Still it’s all about the PERCEPTION of RISK.

WWF-Canada is working to implement a solution that will leave beaver-generated ecosystems intact, while addressing fish passage concerns. With funding from Fisheries and Oceans Canada’s Coastal Restoration Fund and the help of our partners — NunatuKavut Community Council Inc (NCC), Wood (an engineering consultant business), the Atlantic Salmon Federation, the Salmonid Preservation Association for the Waters of Western Newfoundland, the province of Newfoundland and Labrador, and the Beaver Institute — we have already installed four fish-friendly flow devices in Newfoundland and Labrador streams, most recently in NunatuKavut.

Okay, make the fish jump through a box to get around the beaver dam, give them stilts, whatever, just leave the beaver dams alone! Okay?

Fish-friendly flow devices provide a route through the dam for salmon and other fish in case they can’t quite make the leap. This can be particularly helpful during hot and dry periods when the water is not deep enough for fish to use speed bursts to jump, or when the river has been modified by culverts, weirs or bridges that create unnatural “pinch points” in the riverscape. (Beaver dams aren’t a problem in natural conditions, by the way. It’s human infrastructure that can make it difficult for fish to pass.)