A BATTLE of beaver versus salmon is brewing in the rivers and burns around Loch Lomond.

A new licence for the translocation of beavers from Tayside to the RSPB Loch Lomond Nature Reserve has been greeted with anger by angling and fishery groups.

Their fear is that the establishment of the animals in the area could impact on protected species in the Endrick – especially the wild Atlantic salmon, whose numbers across Scotland are in freefall, and the lamprey.

But RSPB Scotland argued that, far from damaging Atlantic salmon numbers, beaver reintroduction is more likely to benefit fish species.

Senior Species and Habitats Officer, James Silvey, said: “Overall the research looking at the interactions between beavers and fish tells us that beavers bring benefits to fish.”

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Gareth Bourhill, secretary of the Loch Lomond Improvement Association (LLIA) was among those who criticised the scheme, expressing “extreme disappointment that NatureScot have approved this application for relocation of beavers from an area in which they openly admit beavers are causing damage and issues for landowners on Tayside.”

One of the reasons for the transfer of the beavers from Tayside is the conflict that exists in the area with agriculture: in 2021, 87 beavers were killed under NatureScot licence.

Mr Bourhill said: “The translocation should only go on if RSPB can demonstrate zero conflict”.

A chief concern for the LLIA is that any beavers released may migrate up the Endrick and Blane valleys and impact on protected species.

“The Endrick Water is a legally protected special area of conservation,” Mr Bourhill said, “with Atlantic salmon and lamprey the qualifying species.

“With NatureScot also being the government quango responsible for the protection of those species, we believe they have a conflict of interest where legally protected species that are, according to Marine Scotland, in decline will now be impacted by loss of spawning areas and obstruction to migration because of beaver introduction.”

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But, said RSPB Scotland, beavers, which were hunted to extinction in Scotland 400 years ago, could bring benefits to these fish species.

This, said James Silvey, is largely because, whereas we humans tend to create “very homogeneous systems”, beavers create “heterogeneity”.

“They bring,” he said, “a diversity to the landscape which fish really need. They create wetlands which is fantastic. They bring debris into the streams which is also great for fish because it gives the young places to hide.”

Research, Mr Silvey said, has shown beaver ponds to have a higher population of invertebrates like dragonflies. One study published in the Canadian Journal of Fisheries and Aquatic Science showed juvenile fish grew bigger and faster inside beaver ponds than they did outside.

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“At a population level,” he said, “when you’re looking at scale, beavers bring benefits. That’s not to say that in very specific areas beavers might bring negative impacts. For example, if there was an area where beavers had dammed a stream that caused problems for migrating salmon.

“However,” he noted, “there are management and mitigation measures that could be utilised in such a situation. A dam could be removed, fish passages put in – a whole range of measures right the way through to the removal of the beavers themselves.”

Among Mr Bourhill’s complaints is that since he heard of the licence application “not a single person from Nature Scotland, Marine Scotland or the RSPB have made direct contact with us.”

The Loch Lomond Fisheries Trust, who collect data on spawning salmonids and carry out conservation and restoration work, also expressed anger at the lack of consultation.

“We are involved in attaching tracking devices and follow our juvenile fish to the Clyde estuary and into the Atlantic,” said its chair, Charlie Frize. “The mortality rate is fearsome at over 90%. We should therefore do nothing to upset the delicate balance of life in our rivers and loch without very, very careful thought.”

The trust voiced worries that beavers burrowing into the river banks would release sediment which will be to the detriment of fresh-water mussels and Atlantic salmon, and that “grant-funded tree planting, to stabilise riverbanks and provide shade for Atlantic salmon to spawn, may be damaged”.

Mr Silvey said RSPB Scotland had spoken “to a wide range of local interests through a 10-week engagement period” and that engagement would continue.

Beavers and salmon, he said, have “co-evolved” for millions of years. “The incredible leaping we see salmon do at Scotland’s falls and fish passes is also done at beaver dams in other parts of Europe and they will do in Scotland as well, where we have beavers. Then once they have spawned and the young salmon travel downstream, hopefully what you’ll find in those areas is beaver ponds holding more invertebrates which will improve their growth rate and the situation for salmon.”