Angry fishermen have made an 11th-hour plea to the Scottish Government to scrap plans to ban them from key catching grounds.
They warned last night that the impact of closing waters around the Western Isles and west coast could be worse than they had first feared.
They said there would be “substantial job loses” if the proposed restrictions were put in place.
The Western Isles Fishermen’s Association (WIFA) also warned the future of two onshore processing plants – which employ more than 70 staff – could be jeopardised.
Now WIFA is urging Environment Secretary Richard Lochhead to reconsider Marine Scotland statistics which are being used to justify the closure of vital grounds.
The association claims fragile communities could suffer “huge losses with no environmental gain”.
It has already held talks with Mr Lochhead in Edinburgh but has now written to him to ask him to abandon the proposals.
Marine Scotland has produced a list of Marine Protection Areas (MPAs), aimed at safeguarding vulnerable habitats and “enhancing the health of Scotland’s seas”.
The measures are due to take effect from October 1.
WIFA secretary, Duncan MacInnes, said: “Clearly, the fishing industry has differing views regarding the methodology used to calculate economic impact and how fishing information is recorded.
“The figures that the cabinet secretary has been given about the economic impact of the proposed closures are also wrong and have completely underestimated the jobs that would be lost.
“The closure of perfectly healthy fishing grounds would force several fishing boats out of the industry with potentially dozens of job losses at sea and on land.
“This would have a devastating impact on our fragile island communities.”
Councillor Uisdean Robertson, who chairs the joint Comhairle Fisheries Industry Group formed to fight the closures, said: “I am extremely concerned about potential job losses among fishermen and onshore processing workers as a result of these disproportionate proposals, which totally underestimate the local impact they will have.
“Islanders have been living in harmony with the environment for hundreds of years.
“We have been fishing these grounds for decades and have seen no decline in scallop stocks – indeed many of the areas earmarked for closure are showing increased populations of mature scallops.
“The proposed closures would force many young fishing families to leave the islands. We have to fight this.”
WIFA plans to provide additional information to officials before the rural affairs committee meeting on September 23.
A Scottish Government spokesman said: “The environment secretary had a productive meeting with representatives of the Western Isles fishing industry and is always willing to hear more evidence from local businesses and fishermen in relation to this issue.
“The Scottish Government’s proposals seek to balance the interests of protecting Scotland’s marine environment with wider economic interests, particularly those of the fishing industry.
“While the proposals would mean a restriction of fisheries within certain areas, fishermen from the Western Isles will still be able to operate in other neighbouring areas.
“No decision on MPAs will be taken before the Scottish Parliament’s environment committee hears evidence on this issue at its meeting next week.”