IT’S a drop in the ocean when it comes to the UK’s wider economy. But in parts of rural Scotland, fishing is no minnow.

The industry is vital to coastal communities in areas such as the north-east, where it has sustained jobs for generations.

But it is the symbolic significance of fishing, and its place at the heart of our island story, that has perhaps led to its disproportionate influence on the Brexit debate.

Fishing accounted for just 0.24% of the overall Scottish economy in 2017, generating £316 million.

In constituencies such as Banff and Buchan, however, it will loom large on December 12.

The former seat of Alex Salmond, who held it from 1987 to 2010, Banff and Buchan was won by the Tories at the last general election. Research suggested it was the only constituency in Scotland to vote Leave.

David Duguid, the local Scottish Tory candidate who is defending a majority of 3,693, is keenly aware of fishing's importance.

"In my constituency, the two largest towns – Peterhead and Fraserburgh – are also, respectively, the largest white fish port and the largest shellfish port in Europe," he said.

"There's been fishing around these coasts for as long as there's been people.

“Of the 650 UK or Westminster constituencies, none are more significant when it comes to fishing then Banff and Buchan."

He added: "A lot of people get tied up on this, 'Oh, it's only 0.6% of the UK's GDP'.

"That's perhaps true if you spread it thinly across the whole UK, but when it's focused in places like Peterhead and Fraserburgh it's pretty much all there is.

"That's why it becomes very important – not just to me and to the people of Peterhead and Fraserburgh, but for a lot of the surrounding area."

Asked why fishing has become such a central issue to the Brexit debate, Mr Duguid is clear.

"Everybody knows that Brexit is good for fishing," he said. "It's become totemic.

"And I think the reason for that is nobody can really argue that the fishing industry won’t be better off as a result of Brexit.

"There's very little argument for staying in the Commons Fisheries Policy (CFP)."

The CFP, which sets fishing quotas for EU member states, has long been a bugbear for fishermen, who argue it is unfair.

Mr Duguid said Brexit would allow the UK to become an “independent coastal state”, setting its own rules.

He said support for leaving the EU remains strong in Banff and Buchan, and many constituents simply want to get Brexit done – including some independence supporters.

"I was talking to one guy just the other day on the doorstep," he said. "He's voted SNP all his life. He wanted independence. He would vote for independence again, but he's a fisherman and above all he wants out of the EU.

"I barely said a word to him on the doorstep. It was one of the easiest canvassing session I've ever had. He just stood there and basically ran through his logic in front of me.

"His shoulders slumped and he resigned himself to saying, 'I'm going to have to vote Conservative in this election to get what I want.'

"You could see it was kind of painful for him, because he had never voted Conservative in his life. But he recognised that in order to get what he wanted, which was to get out of the EU, he was going to have to vote Scottish Conservative."

However Paul Robertson, the SNP's candidate for Banff and Buchan, argued attitudes are changing as the importance of staying in the EU's single market looms large.

"What's coming up a lot more on the door and in conversations with fish processors is they're scared that because Boris Johnson has put the future of quota and access to waters as part of the wider trade negotiations, there's going to be another Tory sell-out – and the Tories have got form on that," he said.

"On the processing side – which is actually where most of the jobs are – the industry is very keen to remain in the single market, which is also not on the table for the Conservatives.

"With 75% of your exports going to Europe, and with 5,000 EU nationals working in fish processing, coming out of the single market would be pretty disastrous for Scottish fishing.

"You would be faced with the situation where you might be able to catch as much as you want, if the Tories don't sell away access to our waters in return for something else, but you would have nobody to sell it to, because of the barriers that would be erected.

"So the industry is starting to come round to a position where they would prefer to stay in the single market, they would prefer to increase their catching opportunity, and the only people who are credible on that are the SNP."

He added: "There's a calculation that the industry is making that there's a heavy risk they will get sold out on the way out of the EU, just like they did on the way in.

"Now, would Scotland get a better deal for Scottish fishing from the EU?

"What you can be guaranteed of is because Scottish fishing is worth 30 times more for the Scottish economy than it is for the UK economy, it's 30 times more important to Scottish ministers than it is to Boris Johnson."

Influential voices such as the Scottish Fishermen's Federation (SFF) have said leaving the EU presents the industry with a "sea of opportunities".

But Mr Robertson said the crucial issue for the SFF is increasing the share of fish for Scottish vessels and retaining access to markets. If this could be achieved with independence, the organisation is open-minded to that.

It's not just the fishing industry in the north-east that has a stake in the debate.

The piers and harbours in areas such as Argyll and Bute also bustle with activity, with Oban styling itself the seafood capital of Scotland.

The SNP secured a majority of 1,328 there in 2017.

Alistair Sinclair, national coordinator of the Scottish Creel Fishermen's Federation, represents hundreds of members up and down the west coast and beyond.

He described Brexit as a “pending nightmare”, adding: “We have major concerns regarding this election.”

Mr Sinclair said Boris Johnson “changes his mind like the weather”, with no guarantees over what the future holds for Scotland's inshore fleet.

“We’re facing an absolute meltdown due to the logistics of the situation if things don’t work out well," he said.

“And there’s no political party giving us any confidence moving forward. The SNP has failed us miserably on so many issues in recent times.”

He added: “We’re facing the difficulty that we might need five different sets of documents before we can actually ship anything across the Channel.

“We could be facing major hold-ups at the Channel, or across the Channel.

“If there’s any hold-ups whatsoever, because we’re shipping live product – that system that’s taken almost 20 years to get working as slick as it does nowadays would collapse and fail, and then we would be shipping product that would have no value to it.

“And if we can’t ship our product, and we don’t have the markets within the UK, there will be no point in us all going to sea.

“So the difficulties that would then be placed on the rural communities around the coastline of Scotland could be horrendous, absolutely horrendous.”

Mr Sinclair is not the only one with major concerns.

James Withers, chief executive of Scotland Food & Drink, said small-scale seafood producers could be out of business in just four weeks if the UK crashes out of the EU.

He said a chaotic exit could be catastrophic for smaller farmers and producers who send fresh produce to Europe.

The total value of Scotland's food and drink exports is £6.3 billion annually, £4.7 billion of which is generated through whisky exports.

Of the remaining £1.6 billion from food exports, two-thirds is sold to Europe.

Mr Withers said there is a “dark cloud hovering over the whole farming, food and drink industry".

Seafood is Scotland's biggest food export to Europe with much of the fresh produce, including salmon and shellfish, landing on French and Spanish tables within 24 hours of being fished.

Proposed tariffs, disruptions at ports and borders, as well as an increase in issuing health certificates for animal produce pose a real threat to the survival of these businesses.

Scotland issues around 15,000 health certificates a year for animal products being exported to the EU but this could rise to more than 100,000 – each at a cost of around £90 to the producer.

Certificates are currently issued by individual councils in partnership with environmental health officers but Mr Withers warns today's system could not withstand the spike in demand following a chaotic Brexit.

Delays at points of entry could see the value of fresh and live products plummet, putting small producers out of business.

Mr Withers said: "We've heard from some seafood businesses that any kind of delay at ports and the loss of that market for even just a few weeks could put them under.

"I believe that some businesses, particularly those reliant on the European market, may not survive even three or four weeks of disruption, such are the potential impacts."

Because Brexit is "haunted by huge unknowns", the farming, fishing and food and drink manufacturing industry is facing a "major shock to the system" with industry chiefs previously estimating that a no-deal Brexit could cost Scotland £2bn in lost sales annually.

Mr Withers said: "We could, in the short term, be unable to get products to the market or in the longer term just face [charging] lower prices because it takes longer to get on to the market and companies profitability will be impacted."