Scottish skippers are threatening legal action over the latest EU deal on white fish catches.
The measures are aimed at protecting cod stocks
The Scottish Fishermen's Federation believes that the new restrictions discriminate against the UK fleet.
The Scottish National Party has also called for a renegotiation of the deal, which saw haddock quotas increase while skippers' time at sea was unchanged.
But Fisheries Minister Ross Finnie told the Scottish Parliament that there was "no going back" on the agreement.
He gave a statement to MSPs on the EU deal, which was struck in December after three days of negotiations in Brussels.
The measures are designed to conserve stocks of cod, which scientists have warned are at an all-time low.
North Sea haddock quotas will increase by 53% and fishermen will be allowed to catch 30% more prawns.
Cod and hake catches have been frozen at last year's level, while Scottish trawlers are still restricted to 15 days at sea per month.
Scottish boats are banned from harvesting most of their quota in large parts of the North Sea - although the same restriction will not apply to foreign vessels.
The Scottish Fishermen's Federation said that the scheme was "unworkable".
It is now considering a legal challenge on grounds of discrimination.
Mr Finnie defended the deal in a statement at Holyrood on Wednesday afternoon.
He said the Scottish Executive had secured better outcomes for fishing businesses, local communities and conservation.
But he admitted that "as long as cod stocks remain outwith safe biological limits our white fish sector will continue to face difficulties".
SNP fisheries spokesman Richard Lochhead said the agreement was "a dreadful result" for Scotland.
He said: "This deal provides more quota in the North Sea but not enough time and space to catch it and it provides plenty of time at sea for the west coast vessels but less fish to catch."
Party leader John Swinney earlier said he was "absolutely certain" that the deal would kill off the remainder of the white fish fleet.
"Ministers often come back from the EU discussions complaining they have been discriminated against," he said.
"This must be the first time Ross Finnie has gone to Europe and volunteered for his country to be discriminated against."
He called on the minister to go back to Brussels to "make it clear that Scotland will not stand for this".
Tory fisheries spokesman Ted Brocklebank said the Scottish white fish sector felt "cruelly let down" by the settlement.
Ross Finnie defended the deal in parliament
Mr Finnie said the executive would consider calls for further aid after the new measures had been studied.
"We will obviously review that and will do so in the light of assessing how these new arrangements impact on different ports," he said.
Green MSP Robin Harper said his party was concerned that transitional arrangements to help affected communities may not be adequate.
But he added: "Only a long-term policy of conservation and rebuilding of fish stocks will give any guarantee of the future of the Scottish fishing industry."
Meanwhile, the Scottish Fishermen's Federation has welcomed signs that the UK government could back demands for more control over traditional fishing grounds.
Chief executive Hamish Morrison said that putting fishermen at the heart of the decision-making process would "help prevent the kind of dog's dinner of a deal done in Brussels last month".
The Downing Street strategy unit is due to publish its report next month.