Understand the Beaver and Salmon Interactions


Conservation and Science


The topic of interactions between beavers and salmon was something I wanted to cover for some time. The most interesting aspect for me was that anglers are usually on the side of nature, conservation and restoration. In this case however, anglers were the group who weren't so keen on the return of beavers to British rivers, despite the unequivocal benefits beavers bring to ecosystems. How strange! Sometimes the "boots on the ground" attitude might be the source of cognitive dissonance. So was this the case here?

One of the main arguments was that the research available at the time wasn't conducted in Britain, so the argument was that it wasn't relevant to local conditions. In search of a relevant guest, I found Dr Rob Needham, who was indeed working in the UK on understanding the impacts of beavers on salmonids. Unfortunately, at the time I couldn't make that episode happen.

Imagine my delight when a few months later I was contacted by Elliot McCandless, a communications manager at Beaver Trust, enquiring about having Rob on the podcast! What a coincidence! Moreover, it turned out that Beaver Trust had made a documentary titled ‘Balance The Scales’ tackling this problem. I know what you're thinking now. Surely it must be biased to "fit Beaver Trust's narrative", a sceptic would say.

Well, and this is where my podcast comes in. I sat down with Rob to discuss the findings of his research. The good, the bad and the ugly. Rob comes from a "fish" perspective and I found his findings objective. It's not all rosy but it's also not deeply problematic. I'm not here to convince you of anything though. What I'd suggest is you listen to our conversation first. Then read Rob's paper 'The impact of reintroduced Eurasian beaver (Castor fiber) dams on the upstream movement of brown trout (Salmo trutta) in upland areas of Great Britain' and watch the documentary "Balance The Scales" once it becomes publicly available.

Beavers vs Salmon - Balance the Scales

Can beavers save Britain's dying rivers? Are these ecosystem engineers the key to reversing the catastrophic decline of Atlantic salmon, or do their dams create impassable barriers for struggling fish populations? With salmon numbers plummeting by 70% in just 20 years and predictions they could vanish entirely within two decades, the stakes couldn't be higher. The reintroduction of beavers to British waterways has sparked heated debate about their impact on our most threatened migratory species.

In this episode, our guest is Dr Rob Needham, and we talk about his research from Scotland. Rob's long-term study reveals how beaver-modified streams support larger, healthier trout populations, with tagged fish successfully navigating multiple beaver dam crossings. We also talk about research from Norway, and North America that's providing crucial insights for British conservation efforts. For example Rachel Malison’s work in Norway demonstrates that beavers and salmon coexist successfully for past decades on some of the world's most productive salmon rivers. The evidence suggests these species co-evolved together and co-existed for millennia, creating complex ecosystems that benefit both.

From the western United States, Bridge Creek's remarkable restoration story demonstrates nature's incredible capacity for self-repair, with 200% increases in fish abundance following beaver reintroduction. Meanwhile, cutting-edge environmental DNA research is mapping salmon and beaver (and other species) distribution across Scottish catchments, showing how ecosystems can recover. As climate change intensifies pressure on freshwater habitats, the ecosystem engineering by beavers offers hope for building resilient river systems. The message is clear: collaboration between conservationists, researchers, and local communities is essential if we're to harness beavers' restorative power while protecting our precious migratory fish.


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Tommy's Outdoors: Conservation and Science

I am an outdoorsman, podcaster and speaker. I talk and write about the natural environment, biodiversity, conservation, hunting and fishing, rewilding and more. I am particularly interested in wildlife and human-wildlife interactions. I enjoy reading scientific papers on those subjects as much as being outdoors weathering the elements and getting first-hand experiences.

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