Angry fishermen fearing for their futures reportedly threw live crabs at police during bloody clashes in France.
Hundreds of demonstrators gathered in Rennes on Wednesday to protest "the regulations and persecution of the direction of maritime affairs", according to an open letter to President Emmanuel Macron.
The sector is facing a costly carbonisation and recruitment crisis.
Olivier Le Nézet, head of the country's National Fisheries Committee, went on to say the treatment of the industry has evoked "aggressions", with French fleets being decreased by more than a quarter in 20 years.
The ill-feeling came to a head earlier this week when the highest administrative court, the Council of State, gave the government six months to close some fishing areas in the Atlantic.
The move was made in a bid to protect dolphin populations in the Bay of Biscay.
Mr Le Nézet said fishermen have been involved in programs to "determine avoidance solutions" to help protect the aquatic mammals while continuing fishing activities for the last five years.
He said 560 of the netters in the Bay are participating in the action plan, and while accepting more can be done, "you can't ask a trawler to become a netter overnight".
"The Council of State has just called everything into question," he said, asking the President for "a pause in this avalanche of bad moves".
Mr Le Nézet has, however, condemned yesterday's violent clashes, which are also said to have seen a tractor reportedly used against the police.
One particularly graphic photo shows a bloodied protestor, with a bandage around his face, being detained by a riot officer.
Under fire President Macron assured fishermen of his support on the issue at the annual Paris International Agricultural Show earlier this month.
It comes as Macron continues to stubbornly resist growing discontent on the streets of his country after his forcing through of a pensions bill without a vote caused nationwide unrest.
He said yesterday the bill - which would see the retirement aged raised from 62 to 64 - must be implemented by the end of the year.
After his interview broadcast on national television, critics attacked Macron, describing him as "self-satisfied," "out of touch" and "offensive."
Some suggested that the president is playing with fire amid strikes and daily demonstrations, some leading to clashes with police.
Unions have called for nationwide protests today that are likely to further raise tensions.
"He is in absolute denial," said Olivier Faure, the head of the Socialist Party.
"It's as though there's a well lit fire and he is pouring jerrycans of gas on the flames."
The president's remarks Wednesday were his first since the government finally forced the pension bill through parliament last week, then survived two no-confidence votes in the lower chamber of parliament on Monday.
France's Constitutional Council will review the bill in the coming weeks, and it can only be turned into law after the body gives its approval.