Just before midnight, David O’Neill navigated his trawler into the harbor in Union Hall, a small port in southwestern Ireland, the wake from the vessel sending tiny waves slapping against the pier.
The crew swiftly unloaded their catch, using a crane to lift ice-packed crates of haddock and hake from the hold of the Aquila under bright spotlights.
Less than an hour later, the Aquila would depart for its final trip. Two days later, the crew stripped the vessel’s contents — chains, buoys, ropes, steel cables, and hooks — and ejected them onto the pier, on their way to a shipyard to be scrapped.
“This is coming with me,” Mr. O’Neill said as he unscrewed the Aquila’s wooden steering wheel. “It reminds you of all you’ve been through on this boat.”
The Aquila is one of dozens of Irish boats being scrapped as part of a voluntary government decommissioning plan introduced after Britain withdrew from the European Union. As part of Britain’s withdrawal, the E.U. transferred back 25 percent of its fishing rights in British waters. That, in turn, significantly limited Irish vessels in the numbers of fish they are allowed to catch — an anticipated annual loss of 43 million euros ($46 million), making Ireland one of the European nations most affected.
Although fishing is a small industry in Ireland, in some coastal communities, it has been the backbone of the economy, even as it has been whittled down over the years. But beyond economics, fishing has been an essential way of life for generations. Locals fear the Brexit quotas and subsequent retiring of boats will be the final death knell.
“It’s bittersweet,” said Mr. O’Neill, 37, who has skippered the Aquila for five years. “You spend most of your time battling the boat. But the boat made us a wage every week and brought us home as well.”
Elsewhere along Ireland’s southwestern coast, in Castletownbere, two fishermen were repairing a net, their hands whipping through the bright green tangle with ease. Behind them, on the pier, stood a memorial to those lost at sea, with dozens of names dating back to 1793 providing a roll call of the dead, linked by family roots and shared tragedy, the same last names repeating through several generations.
At the nearby warehouse for Sheehan’s Fishing — owned by Jason Sheehan, 35, and his father, Ebbie — Jason, who became a skipper at 19, remembers when fishing was lucrative. But new regulations, shrinking quotas and rising gas prices have amounted to “death by a thousand cuts,” he said.
“We have fish, that’s our currency, that’s what we have here,” he said. “So we’re between a rock and a hard place.’”
“There is a lot of disillusionment,” said his father, 64, “because they feel that we were sold out on Brexit.”
The men own a number of trawlers together and have decided to decommission two.
“It was a matter of viability,” the elder Mr. Sheehan said.
The realigned fishing rights affect the entire Irish industry, but the decommissioning plan applies to the whitefish fleet, which could see up to 30 percent of its vessels scrapped. Larger trawlers that fish further off the coast for mackerel and herring, among other fish, are also affected; their fishing season has been nearly halved.
Seven hours north in Killybegs, in County Donegal, the trawlers that have already met their quotas have sat idle for weeks. Visitors to the town are greeted by a strong smell of fish, a reminder of the processing plants dotting the town’s edges, and of how fishing is core to the identity of this place.
“If you removed the fishing from Killybegs, Killybegs would become a ghost town,” said Patrick Murphy, chief executive of the Irish South & West Fish Producer’s Organization.
On a recent Thursday night, at the Fleet Inn in Killybegs, a group of children known as the Wild Atlantic Buskers were performing traditional music. Most of their families go back generations in the fishing community.
As the youngsters played reels on the fiddle, accordion, and guitar, one mother pointed out a boy whose grandfather was lost at sea, a girl whose father worked for a net supplier, and another with family who still fishes here.
At the processing factories, change has already come. Martin Meehan, the general manager of Premier Fish Products, said production had nearly halved since last year.
“I have a son myself, and certainly wouldn’t be looking for him to come into the industry,” said Mr. Meehan, 49.
The decommissioning plan is intended to “restore balance” between the Irish fishing fleet’s capacity and the new quotas, according to the government agency in charge. So far, 42 boat owners have accepted offers to scrap their boats. Payments vary, but for a smaller boat, an average amount might be about $1.6 million, often split among multiple shareholders or a bank.
Cara Rawdon, 64, who has been fishing for four decades out of the northern village of Greencastle, said he received a fair price for his boat. He is retiring.
“There are no young men getting into it here,” he said. Coastal communities around Ireland “are being annihilated.”
Caitlin Ui Aodha, who also fished these waters, sold her vessel and is using the money to open a restaurant in Dungarvan, in Ireland’s southeast.
“You have to adjust, at sea as well as in fishing,” said Ms. Ui Aodha, 60. “You’re out and it’s moving around, and you kind of learn life changes very quickly.”
Ms. Ui Aodha was born in a village in the Gaeltacht, the Irish-speaking area of the country, into a family that had fished for over 150 years. She fished through her early adult years, eventually alongside her husband, Michael Hayes, and then turned to raising their five children, while he continued as a skipper.
But the sea claimed his and four crew members’ lives when their boat sank in a storm near Union Hall in 2012.
After his death, Ms. Ui Aodha bought a trawler and took to the sea again. She assumed she would sell the boat when she retired, but things had been difficult for years, and decommissioning felt like her only option. Her boat was scrapped in late April.
“The saddest thing really is to see how, all around the coast, indigenous fishing people like me become extinct, we’re just not going to be there,” she said, rattling off the names of longtime fishing families. “All these names are disappearing.”
But she also spoke with hopeful resilience about what comes next. The restaurant will be called Iasc, or fish in Irish. Photos of Ms. Ui Aodha’s father with his boat adorn the wall, she pointed out, as she walked through the unfinished space.
“I’ve done what I can and we’ve changed now, and this is just something new,” she said, reflecting on her years of fishing. “So I am bringing my world in here.”
Finbarr O’Reilly contributed reporting.