WASHINGTON (AP) – Millions of casual fishermen reel in a higher take of the nation’s most prized saltwater fish than previously thought, researchers say, prompting them to urge improved regulation of recreational fishing.

Nationally, recreational fishermen landed 5 percent of fish over the last two decades, more than double previous estimates, says a report in today’s issue of the journal Science. But they took 23 percent of fish whose numbers are shrinking.

Scientists urged the government to slow the decline of overfished species. They said current regulations have done little to constrain recreational fisheries, which deplete some major fish populations even more than commercial fisheries.

Regionally, there were sharp contrasts among the catches of declining fish species. In the cool Northeast, it was 12 percent, but in sunny the Gulf of Mexico, it was 64 percent.

The Recreational Fishing Alliance, with 90,000 anglers nationally, said it would fight more regulations. It argued the researchers’ conclusions were based on flawed data.

Felicia Coleman, a Florida State University researcher and co-author of the report, said the data shows recreational fishermen landed more than half the catches of some fish populations.

They caught 93 percent of red drum caught in the South Atlantic, 87 percent of bocaccio snagged off the Pacific coast and 59 percent of red snapper landed in the Gulf of Mexico, according to the report. Bocaccio is a type of West Coast rockfish.

Coleman said researchers did not factor in fish caught and released by recreational anglers, but those “zero” landings still affect the health of fish.

Deep-water dwelling species, like red snapper, suffer high mortality rates when subjected to dramatic pressure changes as they’re reeled to the surface.

“The physiological stress is enormous. Even if they swim off, a lot of those fish will be easy prey because they’re in a stunned condition when they’re released,” she said.

The study reinforces what Bob Jones, executive director of the Southeastern Fisheries Association, says he has seen with his own eyes. Recreational fishing is booming in Florida, where the group of harvesters, packers, processors, importers and exporters is based.

“You wouldn’t have to be a rocket scientist to figure a million recreational boats registered in Florida alone are going to have significant impact,” Jones said. “The sports fishing segment is going to have to come to the table and be regulated in the same manner as everyone else.”

Coleman said marine regulators can take a lesson from their terrestrial counterparts. She suggested that licenses for recreational fishing should vary with species’ local populations, like those issued for deer.

However, Jim Donofrio, executive director of the Galloway, N.J.-based Recreational Fishing Alliance, questioned the reliability of the report’s conclusions and data. For example, he pointed to a reported 35 percent jump in summer flounder catches. In reality, he said, torrential rains had kept anglers onshore, and the catches had dropped by 35 percent.

“We’ll accept regulations. That’s not a problem. But we will fight restrictions based on arbitrary data and inaccurate data,” Donofrio said.

The number of saltwater-dwelling fish that recreational and commercial fisheries get to catch are based on a 1999 study by the prestigious National Research Council. It estimated that recreational fisheries haul in just 2 percent of fish landings.

But the council is negotiating to do a follow-up study for the Commerce Department, said Sue Roberts, part of a board the council set up to advise the government on ocean science.

Greater numbers of fish caught recreationally could have health implications, too.

The Environmental Protection Agency said Tuesday that one of every three lakes in the nation and nearly one-quarter of its rivers were so polluted that people were advised by states to limit or avoid consuming fish caught there.

The state advisories include nearly 75 percent of the U.S. coastline in the 48 contiguous states.

But the concerns for local waters contaminated by mercury, PCBs, dioxins and other chemicals exclude deep-sea commercial fisheries.