The government is to take further steps to try to protect increasingly endangered stocks of fish.

The BBC's Environment Correspondent Margaret Gilmore: If illegal fishing isn't stopped, some fish could die out altogether

Fisheries minister Elliot Morley says there will be tighter controls from the New Year on landings of fish from vessels of 20 metres and over.

There is also to be investment in state-of-the-art radar and other surveillance equipment to help the fisheries patrols.

The new scheme is the latest attempt to end the scandal of what is known as black fishing - catches made in defiance of quotas allowed under the EU's common fisheries policy.

The plan, to be implemented by the Ministry of Agriculture, Fisheries and Food (MAFF) and the Scottish Fisheries Protection Agency, will come into force on 5 January.

Holders of UK fishing licences will have to give at least four hours' notice of their intention to land fish or shellfish.

The catches will then normally have to be unloaded within four hours. But there will be some exceptions when boats land their catches at "designated" ports.

Last March MAFF said vessels over 20 metres would have to land their catches at these 32 designated ports. But most of the UK fleet is made up of smaller vessels.

Tighter controls for trawlers

Landings of black fish have caused enormous damage to fish stocks, which are in any case under severe pressure.

Legal fishing is exploiting many species faster than they can breed. North Sea cod are usually caught before they reach sexual maturity.

Half the landings of the most endangered North Sea species, chiefly cod and saithe, were illegally caught last year.

A senior fisheries inspector who briefed Mr Morley early in 1997 said: "The extent of black fish landings is a national disgrace. It goes on 24 hours a day.

"The greed of the present generation of fishermen will ensure that there is a very poor future for people entering the industry."

Mr Morley said: "The black fish undermines everything we are doing on conservation and management and because of it we will have to cut back even harder."

The problem of black fishing has been particularly bad in Scotland. But the fishermen's supporters say they were encouraged by the government in the 1980s to build bigger boats.