New limits on trawling and sea-bottom dredging threaten jobs in a £50 million a year rural industry, the Scottish Fishermen's Federation has warned, as a row between the Scottish Government and a key Scottish exporting sector threatened to escalate.

The SFF say that restrictions on the £40m west coast langoustine fishery and £8m scallop fishery due to take effect from October, would close 880 square kilometres of inshore waters in the South Arran and Wester Ross Management Protection Areas (MPAs) to scallop dredging and impose economically-damaging restrictions on a further 1500 square kilometres of prime fishing grounds.

The federation claims that draft conservation orders for four west coast MPAs, announced earlier this month, go far beyond what had been agreed during months of talks with civil servants.

The SFF has demanded urgent talks with fisheries minister Richard Lochhead, now expected to take place next week.

SFF president Ross Dougal told the Sunday Herald that, following months of negotiations with the Scottish Government and its environment quango Scottish Natural Heritage, the federation reached what it believed to be an acceptable compromise.

"We thought that we had agreed on something that we could live with, but what the government has put forward bears no relation to that agreement," he said.

"The areas that would be closed to mobile fishing gear [dredges and nets] goes far beyond the compromise that we thought had been reached. We were completely taken aback as the implications for the industry could be immense."

According to the government, the measures will affect less than 3.5 per cent of Scottish territorial waters and will lead to a reduction in income for scallop fishermen who use dredges of only 1.6 per cent and of 1 per cent for prawn trawlers.

Figures published by the government last week put the cumulative impact of the changes on the industry at around £1m a year.

The figure is disputed by the SFF which claims that it does not account for the impact of fishermen being driven out of the industry, or whose overheads increase by extra fuel costs travelling to unrestricted areas.

Announcing the restrictions, Lochhead claimed that the "impact in the vast majority of cases will mean modest changes to fishing patterns with very limited economic impact given the ability of vessels to fish elsewhere."

However, the SFF's claims have been dismissed by the 500-member Scottish Creel Fishermen's Federation (SCFF) which believes that the government needs to go further to protect the seabed of inshore waters from what it regards as damaging fishing practices and is urging the government to stand firm.

Founded three years ago, the SCFF represents scallop divers as well as creel fishermen and claims to represent 80 per cent of the Scotland's inshore fishing fleet.

Alistair Sinclair, the SCFF's national co-ordinator, said that in most inshore waters the interests of fishermen who use mobile gear and creel fishermen are "incompatible".

According to Sinclair, using creels or diving to fish for langoustines and scallops is a sustainable and green form of fishing that inflicts no damage on the seabed.

This is in contrast to the use of dredges or trawler nets which, Sinclair believes, have a devastating effect on the delicate ecology of seabeds as kelp, firework anemones and maerl beds (a coral-like seaweed that provides nursery areas for young cod, scallops and crabs) are destroyed when the heavy metal gear of dredging boats is scrapped along the seabed.

Scallop diver members of the SCFF claim that dredgers often leave a trail of destruction in their wake, with smashed crabs, sea urchins and scallops left to die and rot on the seabed after a boat has been in the area.

In addition, says Sinclair, static creels left on the seabed are routinely damaged or destroyed by trawlers and dredgers and creel fishermen receive no compensation for this.

"What the government has proposed has been welcomed by our members but we think that Richard Lochhead should be bolder," said Sinclair, who believes that the government should consider re-instating a ban on dredging and trawling within three miles of the shore which was abolished in 1984.

The SCFF is also calling on the government to introduce so-called "spatial management" measures which would create separate fishing areas for trawlers and dredgers, on the one hand, and creel fishers and divers on the other.

Fisherman John McLean of Mallaig told the Sunday Herald that he is considering giving up fishing because of the restrictions and it is likely that his 18-year-old son will have to reconsider whether he has a future in fishing.

McLean (54), the skipper of the prawn trawler Caralisa, said: "We have fished the area for generations but now we can longer to do so," he says. "Twenty or 30 years ago there would have been up to 40 vessels fishing these grounds, but now there are only around ten and the fishing pressure is less than ever. I really do wonder if it is worth continuing."