HALIFAX -- Hopes have been dashed for a recovery of the once mighty northern cod stock off Newfoundland, a leading conservation group says.

Three years after scientists confirmed there were signs of a comeback and catch limits were increased, the federal government decided this week to reduce the limit.

Ottawa cited a spring stock assessment that found the cod population had declined 30 per cent after seven years of rebuilding.

However, Oceana Canada says the 9,600-tonne catch limit announced Tuesday -- a 25-per-cent reduction when compared with last year -- is still too high.

"There were some fragile signs of recovery," said Robert Rangeley, a marine biologist and science director for Oceana Canada. "All those hopes were dashed in the assessment this spring."

Northern cod were once the backbone of Newfoundland and Labrador's 400-year-old fishing industry. But the population collapsed in the early 1990s because of overfishing, mismanagement and changing environmental conditions.

A fishing moratorium imposed in 1992, which was eventually extended to other groundfish stocks, wiped out more than 30,000 jobs.

It was the largest mass layoff in Canadian history.

Within a year, the entire $700-million enterprise -- and way of life -- was gone.

But there were initial signs of recovery in 2012, and by 2015 the catch limits started to increase -- that year's limit was 4,400 tonnes, less than half of what it is now.

Rangeley said the biomass of the northern cod population is now estimated at around the same levels as in 1992.

"The projections for next year are no better (because) this stock isn't growing," Rangeley said in an interview Wednesday. "It's well under the critical zone ... It's pretty scary."

The province's largest fishermen's union is arguing that the new catch limit amounts to a "dramatic reduction" that will hurt coastal communities that rely on the fishery as a key source of income.

Keith Sullivan, president of the Fish, Food and Allied Workers union, said the March stock assessment had concluded the fishery was having no impact on the trajectory of the stock.

"This decision (to reduce the catch limit) ignores socio-economic considerations for hundreds of communities in our province and the thousands of people who rely on coastal resources," he said in a statement late Tuesday. "Without it, outmigration will continue and rural life will be a thing of the past, with no industry to support it."

The union said the latest research indicates the population decline can be mainly attributed to natural mortality and not fishing pressure.

Rangeley said he was aware that coastal communities are heavily reliant on the fishery, but he insisted that tougher measures were needed.

"What will they be relying on when there's no fish?" he said. "I understand those communities want to catch more cod, but they would catch a lot more if that stock were allowed to rebuild."

The federal approach ignores scientific advice to reduce fishing pressure to the lowest possible level, he said. As well, the advocacy group said there should be no recreational cod fishing until the federal government is able to monitor catch levels in that fishery.

Federal officials announced Tuesday that the recreational groundfish fishery, which opens June 30, will include 39 fishing days -- a reduction from the 46 days allowed last year.

A spokesman for the federal Fisheries Department was unavailable for comment Wednesday.