Scottish Secretary David Mundell has rejected the idea a UK exit from the EU would be a “panacea” for the challenges facing fishermen.
The Tory frontbencher said there was “no way” a vote to leave would mean simply going back to Scotland or Britain controlling British waters.
But he also conceded fishermen were unlikely to be won over in the final weeks of the campaign.
Remain advocate Mr Mundell’s comments came after research by Aberdeen University revealed 92% of UK fishermen will vote for a Brexit in next week’s referendum.
The survey found more than three-quarters of the skippers who took part anticipated being able to catch and land more fish outside of the EU.
And it showed few were concerned about the potential detrimental impact of a Leave vote on export sales.
Mr Mundell said: “I think the fishermen are wrong in the sense there is no way we would just go back to Scotland or Britain controlling British waters.
“There are a whole host of international rules and agreements even if we were outside the EU which would impact on their activities.
“So it’s not the panacea that’s being suggested. But I’ve encountered fishermen over many years. I know how strongly they feel on this issue and I think they are unlikely to be persuaded in terms of how they cast their vote.
“For the wider public, the people who are open to argument, I would say the idea we would go back to a position where we were entirely in control of our own fishing is not one that is realistic.”
Scotland’s only Conservative MP also called on Nicola Sturgeon to rally support for Remain among SNP voters.
He said: “They were so keen in recent times to point out 1.5 million people voted SNP in the UK general election.
“I want to see them turning all of those people out to vote for Scotland and the UK to remain in the EU.
“If they do, that can make a substantial contribution to getting a Remain vote across the UK.
“Jim Sillars is most obvious but there are a lot of other people within the SNP or who have voted SNP who are a bit sceptical to say the least about the EU.
“Those people need to be convinced and I want to see Nicola Sturgeon and SNP leaders positively going out to convince those people to come out and vote.”
