A MAJOR effort is under way to boost the numbers of trout in one of the rivers of the Yorkshire Dales - by reversing what was once official policy.

The Environment Agency has stepped in to help a fish population that is suffering because of agricultural practices that were encouraged until the 1970s.

The Upper Cover, which runs into the Ure in Wensleydale, is suffering from bank erosion and siltation problems after years of over-grazing and moorland gripping.

The latter is a procedure which was extensively carried out in the 1950s, 1960s and 1970s - sometimes with the help of grants from the government.

It allowed farmers to utilise moorland by gouging deep drainage ruts into the earth, but it led to faster run-off of rainwater into rivers, weakening banks as a result.

In turn, the river has been left too wide and shallow with extremely mobile bed conditions which are not ideal for trout survival, washing out many young fish during high river flows.

And in an apparent U-turn, landowners in the area have now begun a policy of grip-blocking, where the drainage ditches are being filled in.

The work is part of a habitat improvement scheme launched by the Environment Agency with local farmers, the National Park Authority and the Wild Trout Trust.

It also involves the replanting of heather and some fencing by the river bank to stop stock getting close and allowing vegetation to re-establish itself.

The environment is also being improved for the fish by the creation of features such as log weirs and boulder pools.

The plan is to strengthen the riverbanks and provide a more stable environment for the brown trout - and there are even plans to further develop it as a fishing river.

The agency's fisheries officer, David Bamford, said: "By working with the landowners and adding to this scheme, we aim to greatly increase trout survival in this part of the river, which in turn will help the populations throughout the whole of the Cover and the main River Ure."