It is hoped the changes will help revive stocks in the Wye

The change is in the wake of other measures to rehabilitate rearing areas in the upper Wye which should increase salmon numbers.

The river was once recognised as one of the best salmon rivers in the world, but it has seen a decline.

We urge anglers to exercise further restraint through voluntary catch and release of all fish Patrick Darling, Wye Salmon Fsheries Owners' Association

Last year a trust devoted to bringing the salmon back to the river secured funds for improvements.

Anglers will no longer be able to fish for salmon with worm, prawn or shrimp.

They will also be restricted to the method of spinning for salmon during a certain part of the year.

Exploitation

The new by-laws, which will come into force on Monday, aim to reduce exploitation of the salmon stock by about 20 per cent.

Changes on the Wye 3 Mar - 31 Aug: salmon season 3 Mar - 16 June: fly fishing and spinning only with mandatory catch and release of all salmon 16 June - 31 Aug: fly fishing and spinning only 1 Sept on: fly fishing only

This should increase the number of fish surviving to spawn by cutting the number of salmon caught under low water conditions in summer when catch and release is much less effective.

Peter Gough of the Environment Agency said: "We all want to see the Wye stock restored and control of exploitation is an important mechanism to achieve this."

Last November, the Wye and Usk Foundation secured �1.5m bid under the European Regional Development Fund to turn around the river's fortunes.

Anglers are being urged to release all fish after the catch

It removed blockages from the tributaries where the salmon spawn, and cut back vegetation to allow sunlight to promote the growth of the bugs that baby fish eat.

"We desperately need to improve voluntary catch and release rates on the river," said Stephen Marsh Smith, of the Wye and Usk Foundation.

"I urge anglers to take advantage of the recently launched voluntary catch and release scheme.

"Those who return their fish alive and well river will have the comfort of knowing that their fish will have a great chance of spawning.

Patrick Darling, of the Wye Salmon Fisheries Owners Association, said: "We welcome measures such as these that will result in more fish surviving to spawn.

"The Wye stock is currently at a very low level and, in addition to byelaw control, we urge anglers to exercise further restraint through voluntary catch and release of all fish.

"The ban on bait fishing will result in better survival of released fish as will the use of barbless hooks."