Trout movements are restricted for at least a month

The government has imposed a ban on live fish movements across North Yorkshire after the haemorrhagic septicaemia virus (VHS) was discovered.

Harmless to humans, it can destroy trout stocks unless it is eradicated.

MEP Edward McMillan-Scott has written to the European Fisheries Minister demanding special financial assistance for the fish farmers affected.

The Conservative Yorkshire and Humber MEP said: "It seems very unfair that a large number of fish farms should be financially penalised especially if the ban continues and they are forced to destroy stocks."

Many millions of trout are quarantined across the county, with 33 hatcheries and restocking farms affected by the order unable to move their live produce.

The VHS virus was first found about three weeks ago on a trout farm in Nidderdale and later in a grayling sample taken from the River Nidd below the trout farm.

Up to 50,000 infected fish were slaughtered on the farm.

VHS affects mainly farmed rainbow trout and can cause death rates of up to 80%.

Defra inspectors have imposed the quarantine

It was the first outbreak of VHS recorded in mainland Great Britain, although there was an outbreak of the marine form of the disease in farmed turbot in the Isle of Gigha, off the coast of Scotland, in 1994.

Dave Gotto, who owns a fish farm at Glasshouses within the affected area, said he was fortunate as he produced fish for the table and was still able to sell them as long as they had been gutted before leaving his premises.

Mr Gotto, who has about 1m trout on his farm, said: "It is really becoming very difficult for the hatcheries and the restocking farms.

"They are still producing but rapidly running out of space because they are prevented from moving their stock - and the fish carry on growing."

Defra veterinary officers and inspectors are still conducting tests in local waters and the results should be known in July.

A Defra spokesman told BBC News that after the results had been analysed it would review the situation and redefine or reduce the quarantine zone accordingly.