THERE'S a battle being fought along the meandering tributaries of the River Wye just north of Leominster that's every bit as brutal as the American War of Independence.

Albeit on a slightly smaller scale - and this time the Yanks are the invaders.

The protagonists are about three inches long and live in the network of babbling streams that service the Lugg and Arrow rivers, which join near Leominster before flowing into the Wye below Hereford.

They are crayfish. Or, if you remember the track from your 1958 Elvis Presley film album King Creole - as I'm sure you do - crawfish.

And if the winners of this sub-aqua battle turn out to be the American signal crayfish, sightings of the losers, the native British white clawed crayfish, will be rarer in north Herefordshire than Elvis in a chip shop in Lugwardine.

The good news is a cavalry charge on behalf of the white clawed species has been sounded by Defra, albeit accidentally.

The real intention of the Government department grant to the Wye and Usk Foundation was to improve conditions for salmon and trout in the area, bringing back the fish and the anglers which were once so important to the local economy.

Riverbanks have been coppiced and fenced to keep out stock, thus restoring the habitat for fish.

A spin-off from the work has been to improve the lot of the endangered British white clawed crayfish, both by providing better living conditions and also eliminating its US opponent.

Much more robust and vigorous than its home grown cousin, the signal crayfish was first imported into the UK in the 1970s to be commercially bred for food.

But when the live crayfish farming market collapsed over here in the mid-1980s, commercial stocks were either abandoned or neglected. The result was that many of the enterprising signal crayfish did a runner, because they can climb and walk considerable distances. With no one guarding the perimeter fence, they were off and away like Steve McQueen in The Great Escape.

In no time they had taken over streams and rivers formerly inhabited by British crayfish, damaging, plant, fish and other local life.

They burrow up to three feet - or well over a metre - into riverbanks, sometimes undermining them, and as if that wasn't enough, they have spread crayfish plague, which although not fatal to them, does for British crayfish.

Working on fish improvement in the Herefordshire rivers and streams, staff from the Wye and Usk Foundation came across a sizeable population of the American invader and have so far trapped 12,000 of them. As Andrew Peterken, from the Countryside Council for Wales, explained: "We have supported the Wye and Usk Foundation in its work for fish and river habitats for many years, so when we wanted to take some action for the crayfish, the foundation was the obvious partner to approach.

"It did look as if the white clawed crayfish was in danger of extinction on these rivers, but thanks to the foundation, this threatened species now stands a good chance of survival."

Dr Stephen Marsh-Smith of the foundation added: "It is only through partnerships such as this that any reasonable improvements can be made to huge rivers like the Wye and Usk. The white clawed crayfish is a true indicator of success in any river's ecological restoration." And that's one in the eye for Uncle Sam.