Beavers and angling: from separation to assimilation
It seems to me that anglers (especially trout and salmon anglers) should be clamouring to get beaver into their rivers – and where there are already beavers, they should be doing all they can to support their presence. The fact that they’re not all doing so, may speak of the crippling state of nature disconnect even amongst those that spend their leisure time in wild places.
Aside from having clean water and food (both of which beavers help with) the primary factor in determining how many salmon smolts a river can send to sea, or how many trout a river can support – is the amount of suitable habitat. The more suitable habitat, the more fish. Beavers are expert habitat creators. People who work in river restoration do engineering work on rivers to turn ‘straight’ into ‘winding’, to clean gravel, fell trees to pinch flows, pack brash against banks to reduce erosion. Many tasks that beavers will also do, and for free, with no need for carbon emitting engines or plastics or purchased materials, or noisy chainsaws. What’s more – they’ll do it while we sleep!
If you are an angler and anti-beaver, I ask you to ponder and research these points:
Increased insect abundance
Aquatic invertebrates need somewhere to live and something to eat. Aquatic and terrestrial wood meets both these requirements. The more wood, the more inverts, the more inverts, the more fish food.
The process of water passing through a dam – and beaver dams are leaky – filters the water, cleaning it.
Braided channels, often created by water finding its way around beaver dam are a flood ‘energy release valve’. They are superb juvenile fish nursery areas and bring more potential spawning sites to the river.
Beaver activity raises the water table, meaning more water for longer. This is especially important during the summer months and into autumn when trout and salmon eggs are laid in the gravel (often in shallow areas) and spend months there before hatching.
In an effort to address the upcoming demands of climate change, a higher water table will be very useful. Thank you, beaver. Not only to keep more water in the rivers for longer, but perhaps more importantly in wetland creation. Wetlands are very effective carbon sinks where atmospheric carbon can be stored for as long as the wetland remains wet. Once again, thank you, beaver.
Fish refuge sites and habitat
Trees and tree roots are the ‘gold standard’ in fish hidey-holes. Without roots or submerged trees, fish like trout and salmon will use rocks, boulders, weed or whatever they can find. Sawbill ducks can easily chase a parr around a rock and get it, but that’s a lot harder amongst branches or roots. A win-win for such popular fish.
Over time, beaver engineering creates a longer river that holds more water. They transform a straight channel into a meandering course. Naturally a wandering river’s length yields a greater variety of pools and riffles. During different stages of their life cycle, salmonids need different habitat types. Shallow clean gravel to be born into, thin riffle 0-20cm for fry, 20-40cm for parr, the same and deeper riffles for smolts, and deeper holding water for adult fish. This extra habitat means the river can have a higher fish carrying capacity.
The removal of ‘fines’
‘Fines’ or fine sediment, present a growing problem for salmonid survival on many of our waterways. There are more ‘fines’ in rivers now due to grazing and trampling of river banks, mostly by livestock. Grazing severs young trees before they (and crucially, their root systems) can become established. An accumulation of ‘fines’ can starve the oxygen out of a redd (salmon/trout nest) and kill the eggs. Fines also mask suitable spawning habitat, forcing future spawners to look elsewhere for a suitable site to lay their eggs. Although a few aquatic invertebrate species do well in fine sediment, most require clean gravel with a flow of oxygenated water through it.
Beaver dams and ponds slow the flow of water such that the ‘fines’ leave the flow and collect – usually against the bank. Whilst creating a gradient of sediment that appeals to most fish, the layers strengthen the bank against future erosion, Biodiversity is dependent upon variety. The variety of depths and flow speeds in rivers with beavers, are far greater than those where fallen trees are removed.
The ‘dappled effect’ that results from coppiced trees, creates bodies of water with a varied temperature – appealing to the needs of different fish.
Even a cursory look at the areas of the world with the greatest salmon, sea trout and steelhead numbers, reveals a map of beaver presence. Alaska, Canada, the Kola Peninsula in Russia, Kamchatka, to name a few.
More wild Atlantic salmon return to Norway than any other country. Seven of the top 10 salmon rivers in Norway all have beavers. Six of those rivers are at capacity.
Beaver dams do not block fish passage
If pressed, salmon can jump pretty well, their Latin name ‘salar’ means ‘leaper’, after all. Several studies have investigated whether beaver dams obstruct fish passage. Beaver dams are inherently ‘leaky’ in design, and many times the fish have been seen to surpass them.
A final thought
There is an image that lingers with many Brits, stemming from Victorian times. It’s an image of total dominion over nature with humans at the centre. All blades of grass must be in their proper place, the chosen animals and plants present whether they belong or not (peacocks on the lawns, western red cedars in the arboretum), all so called ‘vermin’ disposed of. The anthropocentric view. It seems to me, to deny the best of what nature ‘is’.
Beavers belong here. Beavers are part of the system. The same system that includes salmon, and should (were it not for our wilful self isolation) include us.
It’s time to change the way we think about the natural world and our role in it. It’s not just ‘our earth’ – to be used and abused to meet our whims. Nor is it an extensive garden that needs to be manicured half to death. It’s a place we share. We teach our toddlers to share with ‘the other children’, but we seem to neglect the lessons on sharing with other life forms.
I believe that the greatest joy in experiencing the natural world is in embracing and observing what it wants to do. Let us realise that we are part of the natural world, not separate from it. Feeling separate from nature keeps us in a state of suffering, we have to continually ‘fight’ nature to make it look or be the way we want. This is not a recipe for a peaceful life. Separation from nature, and each other, may well be our greatest ill. It’s time we take a step back, and let nature do it’s thing.
Duncan Pepper Beaver Believer
Duncan is an environmentalist and runs Fishinguide Scotland, a small company with a focus on fostering a love for the wilds. He has worked with fisheries trusts and schools on river restoration projects and awareness raising agendas.
The blogs that Beaver Trust posts are written by independent authors whose opinions we may or may not share. Beaver Trust is pleased to publish a range of opinions and encourages dialogue and debate.
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© Duncan Pepper 2020.