REINTRODUCING the beaver could have a positive impact on Scotland’s wild salmon populations, according to new research.
Fishermen have long warned that dam building by beavers can harm fish stocks by inhibiting migration.
A study funded by Scottish Natural Heritage indicates that although the dams can impede the movement of fish and reduce the availability of suitable spawning habitat, the harm can be offset by the benefits of increased habitat diversity and a resulting abundance of fish associated with beavers in the environment.
Beaver reintroduction has been a contentious issue since 16 of the animals were released in Argyll in 2009 and 2010 as part of a scientific trial.
Even more controversy surrounds the establishment of a breeding population of escaped beaver on the River Tay, which has led to calls to trap and kill them to prevent damage to fisheries.
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The research reviewed more than 100 sources of information in which benefits were cited 184 times while negative effects were mentioned 119 times.
Beavers were found to help fish by increasing the variety and area of habitats in streams. Dams and ponds increased the abundance of invertebrates, which form the main component of the diet of many fish.
The study also reported the findings of a survey of 49 fisheries managers, scientists and beaver ecology specialists. More than half believed that the overall impact of beavers on fish populations was positive.