Britain's departure from the European single market will disrupt many long-standing economic relationships and could yet devastate one of the oldest -- the Belgian fishing fleet's work in UK waters.
In 1666 -- three centuries before Britain joined the European Union -- King Charles II granted the Flemish city of Bruges the right to send 50 boats to fish off England in perpetuity.
Since then the port of Bruges has silted up, the world's seas have been divided into exclusive economic zones under a United Nations convention and the European Union has launched a common fisheries policy.
But Britain left the EU in January, and negotiators have failed so far to agree on a new way to assign fishing quotas as it regains its status as an independent coastal state.
This could end the fishing relationship, sealed by a grateful English king returning from exile in the Low Countries, that remains a way of life and an economic lifeline for the Flanders coast.
The life of 50-year-old Robert Campbell, a deckhand on the trawler Den Hoope, is itself as much a symbol of the bond as the 17th Century "Fisheries Privilege" charter in Bruges' civic archive.
Robert is now Flemish, but he was born in an English fishing port, where his father died when he was young.
"My stepdad was also a fisherman," he told AFP as the six-strong crew unloaded crates of sole and plaice on the dockside. "He always fished in English waters, went in English harbours.
"He met my mother and we all came to Belgium when I was five years old," he said.
Robert joined a boat when he was 15 and has worked in British waters from a Belgian port ever since. The fishing strategy that brought his family together continues to this day.
The Den Hoope's catches from Dutch or Danish waters are landed in Ostend, but once their 12 tonnes of fish and crabs are unloaded here they set sail for Britain.
When the hold is once more crammed with fish they will land in Liverpool, northwest England, or Milford Haven or Swansea in Wales, to unload while their haul is fresh.
The catch is then transported in lorries through England and the Channel Tunnel and then on to Belgium to be sold at auction in Ostend, the boat's home port.
Belgium's fishermen, therefore, face two threats from Brexit.
If the small fleet loses its access to British waters -- the source of between 50 and 60 percent of its revenue -- it could simply become unviable, the boat owners' association warns.
And even if the tortuous negotiations throw up a deal that preserves Belgium's quotas, the return of a customs and regulatory border at the Straits of Dover will cause traffic jams.
- 'Think about us' -
Hundreds or even thousands of trucks will have to wait for the tunnel and cross-Channel ferries, and if the fish doesn't make it back to Ostend shortly after it is landed, it won't be fresh.
Marc Vieren, an official with the Rederscentrale, a professional association that represents boat owners, says the industry could perhaps survive losing access to inshore fishing within Britain's 12-mile limit.
But if Brexit closes the deeper waters of Britain's maritime economic zone, "it's a catastrophe for us."
The best of the rays and turbots landed by the Den Hoope go to restaurants like the seafront eateries on the other side of the Noordede river in Ostend's beach resort.
But these have been closed by the coronavirus lockdown, and prices have fallen 20 percent since last Friday. The fleet has left some boats idle to avoid flooding the market.
Before the epidemic, the Belgian boats were having a good year, and the Ostend owners have ordered at least three new vessels from a Dutch boatyard. One is already at the quay being fitted out.
"If they say that we can't fish in the English waters any more, all the ships, all the owners of the ships, they'll have to sell," says Campbell.
"All the people that sail in them, the houses that they bought, it's going to all go down. I don't know if the ministers and the politicians can give us the money, I don't think so.
"No deal? Nobody knows what it means 'no deal'. Only the politicians know," he exclaims. "I hope they think about us."
- 'No survival possible' -
Emiel Brouckaert, director of the boat owners' Rederscentrale, says his association has teamed up with colleagues from other EU nations as the European Fisheries Alliance to lobby for a solution.
The industry has had direct contact with EU negotiator Michel Barnier and has the backing of the Flemish and Belgian governments -- despite its relatively small size in the Brexit puzzle.
"It's true that with our colleagues we've been able to push the sector to the front," he told AFP in Zeebrugge.
"When you look at the balance sheet, in terms of gross national product, it's not that great. But it's clear that no survival is possible if we don't have access to British waters."
For the moment, in public at least, the EU leadership -- especially President Emmanuel Macron's government in Paris -- has stood up for EU fishing against British Prime Minister Boris Johnson's brinksmanship.
There can be no question, French and Dutch officials say, of leaving the fishing question until last in the Brexit talks in the hope of using it as a bargaining chip to secure a last ditch trade deal.
But time is running out, and -- in the spirit of the 1666 charter -- Brouckaert's team wants to treat fishing as separate from the broader picture of EU-UK ties.
"As soon as there's the certainty of a 'no deal'," he said. "We need to talk specifically about fishing ... to re-establish our rights."