BOSTON – A mistake scientists made collecting data used to measure fish stocks likely had no significant effect on fish counts, federal researchers said Friday, a decision scoffed at by some fisherman.

The report by the National Marine Fisheries Service was based on a detailed statistical analysis and subjected to peer review, officials said.

“We are convinced that right now we have solid evidence that nothing appeared out of the ordinary, based on the history,” said John Boreman, acting director of the Northeast Fisheries Science Center.

Boreman said sweeping new fishing restrictions – called Amendment 13 – remain on track to be enacted in August. Fishermen and legislators, including U.S. Sens. Edward Kennedy, D-Mass., and Olympia Snowe, R-Maine, have called for a delay until questions about the mistake are resolved. Fishermen say more restrictions will wipe them out.

In September, regulators acknowledged unevenly setting cable on a research vessel that collected fish samples between winter 2000 and spring 2002. Fishermen said the error could result in undercounting fish and create a more dire picture of fish stocks than exists.

Gloucester fisherman Sam Novello, who cooperated with regulators studying the impact of the error, said it makes no sense that such a serious mistake would have negligible results.

“The whole thing is a farce,” Novello said. “It’s the government just trying to cover their butts.”

Fisheries service officials said the report is an objective look at the available data, and it is being analyzed at the Center for Independent Experts at the University of Miami.

Steve Murawski, head of groundfish assessment at the National Marine Fisheries Service, said 10 statistical comparisons of data from faulty trawls with data from properly done trawls showed no significant differences.

Scientists also compared catch results from the faulty tows, done by the research vessel Albatross IV, with those from a correctly fitted survey vessel, the Delaware. They found the Albatross’ catch actually improved relative to the Delaware after the mistake.

Even under a worst-case scenario in which the faulty net missed half the available fish, scientists said their analysis showed only one stock, the New England yellowtail flounder, with appreciable improvement.

Murawski said that doesn’t indicate the survey tows have little value, but rather that many stocks are a long way from recovery.

Results of the survey trawls are just one of many variables in calculating fish stocks.

Federal scientists aren’t done studying the effects of the mistake, but Portland, Maine, fisherman Jim Odlin said properly evaluating it would take at least two more years.

Odlin was among six fishermen who told federal regulators in a letter Thursday they’d no longer participate in the ongoing study of the error, saying they didn’t want to help researchers “grope for the easiest possible out.”

Odlin said legislative action is probably the fishermen’s best hope to delay the new regulations. On Thursday, Kennedy and Snowe asked for a legislative freeze of Amendment 13.

Eric Bilsky, an attorney for the environmental group Oceana, said the report is proof the mistake didn’t have serious consequences and there’s no reason to delay the rules changes.

Also on Friday, the fisheries service released its latest stock assessments, showing fishing rates have declined for 15 of 19 stocks between 1994 and 2001.

But the report indicated major reductions still are needed in several major stocks. For instance, fishing effort needs to be reduced by 51 percent on Gulf of Maine cod and 53 percent on Georges Bank cod to reach levels regulators say are needed to keep the stock healthy.