WATERWAY managers want to exterminate American troublemakers lurking in the Basingstoke Canal.

It may only measure 10 centimetres in length, but the American signal crayfish is weakening the canal’s banks, according to Phil Allen, countryside officer at Hampshire County Council, which jointly manages the 32-mile waterway.

He spoke to members of Odiham Parish Council as to why they should keep contributing £4,000 a year for the canal’s upkeep.

Mr Allen said of the little shellfish with big claws: “We want to annihilate them, basically.”

He added: “They are one of the biggest causes of subsidence. They burrow through the canal wall and it causes a problem.”

The American signal crayfish was introduced to the UK in the 1970s and sold to farmers so they could diversify their produce.

But some of the crayfish escaped and found their way into British waterways.

The species is capable of carrying a crayfish plague which can kill native species of crayfish. The Environment Agency has urged people who catch the crayfish to kill them humanely.

Philip Riley, chairman of the Surrey and Hampshire Canal Society, a group of volunteers helping maintain the canal, said he has seen anglers fishing out buckets full of the unwanted crayfish.

He added: “I was amazed by the size and number of them. We would like to see the back of them.”

In his presentation, Mr Allen also talked of a £75,000 project to repair the towpath at Swan Bridge, North Warnborough, which was damaged by a heavy vehicle.

The talk was arranged by Mr Riley after he heard that the parish council were looking at whether they should keep funding the canal.

A decision will be made before the start of the new financial year.

Mr Riley told The Gazette that the canal provides income for Odiham pubs and shops from people on boat trips, including the society’s John Pinkerton boat.

He added: “If you add it all up, the canal does one hell of a lot for Odiham and £4,000 a year is good value for money.”