The carcasses of hundreds of striped bass washed onto the beach at Napeague Sunday afternoon, and there is speculation that commercial fishermen were to blame.

The fish began washing up shortly after noon on Sunday, according to several recreational fishermen who were in the area at the time. The dead fish were scattered in the ocean and on the sand along a stretch of beach east of Atlantic Drive, an area referred to as White Sands, for the resort of the same name on the beach there.

“It ran for a good mile,” said Dan Loos, who was driving along the beach Sunday afternoon. “There were three or four here and there in the surf and on the beach. It had to be a couple hundred at least.”

Some of the fish were still flopping weakly, Mr. Loos said.

Bill Fonda, a spokesman for the state Department of Environmental Conservation, said on Monday that the agency had received several phone calls about the dead fish and that an environmental conservation officer investigated, but was unable to find any evidence. The officer drove west along the beach for 2 miles at about 5 p.m. on Sunday, Mr. Fonda said, and saw no signs of dead fish.

But the smell of rotting flesh was detectable by the drivers of cars traveling on Montauk Highway, a witness said.

“We could smell them before we saw them,” said Jane Lahr, who was walking on the beach near Atlantic Drive on Monday morning. The birds were “picking at them.”

Most who saw the dead fish were recreational fishermen who blamed commercial fishermen for the waste.

”More than likely, I would say, it was a gillnetter,” said Willie Young, president of the Montauk Surfcasters Association, a recreational fishermen’s group. “Sometimes they get selective. If you sell a bigger fish you get more and the season is long so you have a long time to do it so they dump the ones they don’t want to take.”

Some fishermen have been known to pick through a haul of fish, taking only the most valuable ones, and tossing the others overboard, even if they are dead, so that they won’t be counted toward their legal quota, a practice known as highlining.

Another explanation could be that trawl fishermen, or draggers, are permitted to keep only 21 striped bass per trip. If one of the many trawl boats working in the ocean off the South Fork were to get a large number of striped bass in its net, most of the fish would have to be thrown back, dead or alive.

Stuart Heath, a commercial fisherman from Montauk, said that the fish washed up on the beach on Napeague could not have been killed by one of the East Hampton fishing crews who harvest fish with gillnets from the surf because the beach in the area of White Sands is too narrow for surf boats to be launched by trucks. The gillnetting crews, who switched over from haul seining, are also extra careful not to leave any waste behind, he said, because of the criticism that their former netting practices drew from the public. Haul seine fishing was banned in 1987, but the crews have continued to use their trucks and surf dory gear to fish with gillnets.

“Those guys catch so much flack anyway, they don’t even leave a dead dogfish behind,” said Mr. Heath, who fished in Amagansett with one of the surf crews on Saturday and Sunday.

He said several gillnetters working from boats out of Shinnecock Inlet have been fishing for striped bass off the beach near East Hampton and Amagansett in recent weeks.

Gillnetters can select the size of fish they want to catch by using nets with different sizes of mesh. Gillnets snare fish that swim into them behind the hard plate of cartilage that covers their gills. State regulations require that a gillnet used for striped bass be at least 6 inches across, though most fishermen use 6.5 inch mesh or larger so that they catch only larger, more valuable fish.

Commercial fishermen are also restricted in the number of individual striped bass they can keep each year. Each fisherman receives a set number of tags that must be affixed to any fish they keep. This year striped bass license holders got 241 tags.