Several people have been fined after a protest in London over the post-Brexit fishing agreement.
Police confirmed that fixed penalty notices had been issued to 14 people.
Seafood hauliers descended on roads near 10 Downing Street and the Houses of Parliament in response to the issues they have faced in exporting seafood to the European Union, saying they were being "tied in knots with paperwork" by the new rules.
Trucks with slogans such as 'Brexit carnage' and 'incompetent government destroying shellfish industry' were parked in the area.
Exports of fresh fish and seafood have been severely disrupted by delays since the UK's transition period ended on 31 December.
The new checks and paperwork have been causing big delays for the industry since the UK left the EU, with seafood producers growing increasingly frustrated at the lack of government action.
Lorries transporting freshly-caught produce have been held up at distribution hubs and many have struggled to enter into France.
A spokesman for the Metropolitan Police said: "Police are aware of a protest in Westminster relating to the UK fishing industry - an appropriate policing plan is in place.
"We would remind those involved that London remains in Tier 4 for Covid restrictions and anyone breaching the regulation will be reported.
"No arrests occurred, but a number of lorries have been stopped and 14 people, who were either drivers or passengers in those vehicles, have been reported via FPN (fixed penalty notice) for Covid-related offences."
Yesterday, UK Foreign Secretary Dominic Raab claimed the delays were just "teething problems", adding: "I'm not convinced that that is the result of the agreement."
Many Scottish fishermen have not been able to export their stocks to Europe since the start of the year after the introduction of catch certificates, health checks and customs declarations added lengthy delays to their delivery times, prompting European buyers to reject them.
Some have taken to landing their catch in Denmark to avoid the "bureaucratic system" that exports to Europe now involve.
A spokesperson from Scottish-based DR Collin & Son, who took part in the protest, said: "The industry is being tied in knots with paperwork requirements which would be easy enough to navigate, given that companies have put in the time and training in order to have all the relevant procedures in place for 1st January 2021.
"However, all the training is going to waste as the technology is outdated and cannot cope with the demands being placed on it - which in turn is resulting in no produce being able to leave the UK.
"These are not 'teething issues' as reported by the government and the consequences of these problems will be catastrophic on the lives of fishermen, fishing towns and the shellfish industry as a whole."
Alasdair Hughson, Scottish Creel Fisherman's Federation chairman, said: "It is inevitable that the UK Shellfish industry would want to make its voice heard loud and clear on this matter.
"After the year that all of these businesses have had, struggling to survive against the odds, now faced with this situation, to now find themselves being blamed for not completing forms correctly when they are all just trying to follow government guidelines which are unclear and changing all of the time.
"If this debacle does not improve very soon we are looking at many established businesses coming to the end of the line."
"We strongly feel the system could potentially collapse," said Gary Hodgson, a director of Venture Seafoods, which exports live and processed crabs and lobsters to the EU and which had trucks parked near Downing Street.
"Prime Minister Boris Johnson needs to be honest with us, with himself and with the British public about the problems for the industry."
Mr Hodgson said he had cancelled several lorries since December due to the onerous red tape involved with exporting to the EU.
He said one operator needed 400 pages of export documentation last week to board a ferry to the EU.
"Many fishing communities did vote to leave but I don't think anyone who did anticipated being constrained by documentation and restrictions that have now been thrust upon us."
"We need to bring the country together now and find workable solutions to limit the damage to the economy and to protect jobs."
Additional reporting Reuters