Carl Coppenrath can remember the days when it seemed bluefin tuna fishermen could walk on water.

In the heyday of the 1980s, the market was so flush in Menemsha that fishermen could literally walk across a harbor packed with a fleet of commercial vessels lined up at the end of the day to sell their catch for top dollar.

The mystique and allure of catching the torpedo-shaped fish that can weigh over 1,400 pounds brought glory and the prospects of such wealth that it awoke the romantic reimagination of the old whaling days of the Island. So much so that it spawned the popular cable TV series Wicked Tuna and lit up social media with photos and boastful tales of the trophy fish.

“It’s like an addiction . . . the thrill of hauling one of those things in,” Mr. Coppenrath said. “It really is. It hooks you more than drugs, alcohol or anything. I’ve lobstered, scalloped, groundfished. Nothing compares.”

But Cape and Island fishermen like Mr. Coppenrath agree that the heyday of the commercial tuna industry has long since passed. And many fishermen have moved into more reliable, and perhaps less exciting, markets.

The quiet demise of the tuna industry was in evidence last week when the 278-metric ton seasonal quota was reached early. Market prices were reported to have plummeted to a record-breaking low.

Rory O’Donnell, sales and purchasing manager at Red’s Best, one of the largest wholesale distributors of fish in Massachusetts, said he was paying an average of $4 per pound for bluefin tuna this season, which began in June and normally would have run until the end of August. Last year he paid an average of $7 per pound, $7.50 the year before that, and so on back to the 1980s, when it was worth upwards of $15 per pound.

“It’s just the market in motion,” he said. “Prices are at a significant low because of an increase in competition . . . an increase in farmed fish from other parts of the world that have spilled over from the Japanese market . . . and a higher quantity of fish because of [the fact that] the stock is strong.”

He said while wholesale market prices are low, retail prices have remained well above $20 per pound. The economic anomaly is due to lower quality fish in local waters, which have less meat and fat content when dressed, and also the increased cost of icing and transporting the fish, he said.

Dr. Molly Lutcavage, director of the Large Pelagics Research Center in Gloucester, said the poor quality of the fish is directly related to the biological history.

“If a bluefin has just come all the way from the Gulf of Mexico and hasn’t fed well . . . or if they have just depleted all their fat storage through spawning . . . you can expect a lower market-quality fish,” she said.

Alex Friedman, a bluefin tuna fishermen from Edgartown who has turned to the more sustainable and steady trade of oyster farming, used his cell phone this week to host an impromptu conference call with three former tuna fishermen, who all spoke about the complex factors that have caused the downturn of the once-profitable market. Among other things, they cited more competition due to an open access fishery, with commercial licenses available for less than $30, and tight federal regulations and quotas that leave local fishermen unable to compete in international, less regulated markets. But they were also concerned about the misrepresentation of the tuna industry by reality TV shows and social media.

“It represents the insecurity of the entire industry,” Mr. Coppenrath said. “Nobody is taking any photos with a load of their scallops.”

Now approaching retirement, he spoke of the early days of catching bluefins, which at the time were called horse mackerel. Growing up in Green Harbor in the 1960s, he frequented Vineyard waters on charter vessels when bluefins were only caught for sport.

“We would bring them in, take pictures and dump them at the valve to rot or sell them for five cents a pound to be ground up for cat food,” he said. “At the time there wasn’t any market for them.”

Due to demand from Japan, the bluefin market exploded in the late 1970s, peaking in the 1980s and early 1990s. When Mr. Coppenrath pulled his 30-foot Vineyard Hawk, Anne-Ellen, into the Menemsha or Oak Bluffs harbor, he could easily unload the fish to one of many eager buyers.

But the value of the fish then, coupled with unsustainable fishing practices such as purse seine, longlining and a high quota, led to the collapse of the fishery and a subsequent increase in regulations to deter overfishing.

Brad McHale, fishery management specialist with the National Marine Fisheries Service, said by the early 2000s regulatory measures reached an all-time high and the quota reached an all-time low. But he said there were signs of the eventual demise of the industry long before significant regulations were enacted.

“Currently the bluefin tuna stock, or western Atlantic bluefin tuna stock, is not subject to overfishing,” Mr. McHale said. “We are seeing a very strong abundance of the fish.”

Against a backdrop of increasing stocks, the quota has progressively increased in the past few years. But Mr. McHale acknowledged that increased competition has stopped fishermen from reaping the potential benefits of an increased quota.

He concluded: “It is very difficult to have the government micromanage the market. That is for fishermen and dealers to figure out.”

Mr. Coppenrath is now helping to spearhead a collaborative movement among fishermen, markets, researchers and government regulatory agencies.

Three years ago he launched an organization called the Superfish Tracking Research Partnership. The mission, he said, is to demonstrate why an increased awareness of the bluefin tuna industry is important for conservation, health, the economy and the environment.

It is a fight he is not giving up any time soon. And when the quota reopens on Sept. 1, he will be back out on the water.

“I couldn’t walk away, nobody is doing anything for the industry,” he said. “To get up in the morning and go and catch a bluefin tuna, it’s a sexy thing. That’s why people want to do it. But what’s happening now, there’s nothing sexy about it.”

Corrected from an earlier version which misspelled the last name of Dr. Molly Lutcavage. Her title is director of Large Pelagics Research Center in Gloucester.