European beaver could help save wild salmon stocks

The State should draw on the expertise of the European beaver to restore river habitats and save the wild salmon, according to a Co Waterford fishery owner.

Nicholas Grubb, who owns the Dromana fishery on the river Blackwater, says recent trials in Scotland show the beaver's potential for improving river habitats.

“This would be far more economic than continuing to pour vast sums into scientific research while wild salmon stocks continue to decline,” he says.

The semi-aquatic, plant-loving European beaver (Castor fiber) was hunted to near extinction in the early 20th century, but three families of beavers from Norway were re-introduced in Argyll, Scotland in 2009.

It was the first licensed release on record of a mammal species in Britain, and an estimated 10 million people watched, listened or read about it at the time, according to the Scottish Beaver Trial’s final report.

Mr Grubb points out that the beaver’s well-known dam-building skills and its ability to fell trees improves riverine habitats for other species.

By clearing trees, it allows for more light and creates small ponds where fish, frogs and other species can thrive.

The State’s 2007 ban on drift-netting for wild salmon at sea and the introduction of a tag-based catch system for anglers within individual rivers has not led to the recovery of the stock which had been predicted at the time, Mr Grubb says.

“Scientists are telling us that there has been an escalating level of sea losses, as smolt going out to their north-eastern Atlantic feeding areas are simply not returning in the numbers expected,” Mr Grubb said.

“The scientists tell us that survival is down to around five per cent, from a past level of 40 per cent,”he notes, and this is attributed to climate-change, mass harvesting of krill and sand eel to provide feed for fish farms, hunting by cormorants, and damage to smolt by sea lice larvae associated with aquaculture.

However, smolts may not be as resilient as they used to be, due to a combination of factors, including pollution and tunnelling over of small streams which has deprived nursery areas for trout and salmon of sunlight, Mr Grubb added.

“Spawning in the main channels leads to over competition and excess predation in those local areas, as well as a smaller weaker smolt being produced.”

Salmonids born “way up the small dendrites” or branches of rivers lead to a stronger, earlier specimen heading out to sea, he said.

Mr Grubb says river branches should be opened out and re-seeded with fish.

Farmers should be encouraged to maintain river banks, Coillte and private forestry owners should ensure planting does not take place at the water's edge, and there should be no further removal of weirs, he says.

Mr Grubb believes Ireland should adopt the North American model of State control, which would involve a dedicated department for inland fisheries and wildlife.

Ireland currently has about 2,500 non-native species of plants, mammals, fish and insects, with 48 ranked as “high impact” and 78 species of “medium impact”, according to the National Biodiversity Data Centre.

There is no evidence that the European beaver ever reached Ireland, but its introduction here could be strictly controlled, Mr Grubb says.