He has written to UK transport secretary Chris Grayling to demand that critical exports are given priority access to the additional ferry capacity secured by the UK government when it is not being used to transport essential supplies.
The UK could exit the European Union without an agreement on trade with the remaining 27 members states on Friday if MPs don’t approve Prime Minister Therese May’s Withdrawal Agreement or come up with a plan that would allow all of the EU’s other 27 states to agree to an extension of its membership.
Matheson voiced concerns that the Department for Transport has failed to take action despite the issue being raised in previous correspondence from the Scottish government.
He said: “With an annual value of £944 million, seafood accounts for 58% of Scotland’s total food exports.
“Seafood is highly perishable and therefore dependent on the sort of swift and reliable transport connections which would be damaged by a disorderly UK exit from the EU.”
More than half of that £944m value - £505m - comes from exports of Scottish salmon.
“The Scottish government has, on a number of occasions, sought to have seafood and other time-critical exports prioritised through Kent and Dover,” continued Matheson.
“We have also asked that these exports are given priority access to the additional ferry capacity secured by the UK government where this is not required for essential supplies. So far, these requests have been refused.
“This lack of support for exporting businesses, which threatens the livelihoods of many in Scotland, especially in our more remote and rural communities, is of great concern to us and to the industries affected.
“The current situation, which puts at risk jobs and livelihoods, is simply not acceptable.”
‘Only goods critical to welfare’
He is asking the UK government to look again at the issues of prioritisation, and at what assurance it can give businesses that their critical routes to market will be maintained in the event of a no-deal.
A UK government spokesman said: “Leaving the European Union with a deal remains our priority but we continue to work with Scottish industry to prepare for all possible outcomes.
“As agreed by ministers across government, only goods critical to the preservation of human and animal welfare – such as medicines – will be given access to the government-secured freight capacity.”
Unused capacity will be released for sale on the open market and will be available to all suppliers.