ST. JOHN'S, N.L. -- Northern cod stocks off Newfoundland suffered a steep decline over the last year, with Fisheries official finding the species has a lower survival rate and will likely continue to decease in the coming year.

The bleak findings were part of a report released Friday that said the stock dropped 30 per cent over the last year in the fishing area known as 2J3KL that stretches from southern Labrador to below the Avalon peninsula.

Fisheries biologist Karen Dwyer said there was a large increase in the species' natural mortality, or deaths due to factors other than fishing. That includes warming water temperatures and decreases in their food sources, such as shrimp and capelin.

"We have fish that are in poor condition and all those things taken together indicate that something in the ecosystem is happening to cause these mortality levels," she said in an interview.

"They could be starving, they looked skinny, they're just not healthy fish. ... (The ecosystem) is in flux at the moment."

Dwyer said survival rates have shifted from 70 per cent in 2016 to 48 per cent in 2017.

The cod stock remains in what Fisheries calls a "critical zone." The department said the stock had been showing improvement since 2012 with ups and downs along the way, but posted a sharp overall drop last year.

"It's the biggest blip we've seen," Dwyer said.

Still, she said the harvest rate continued to climb in the last several years, suggesting there needs to be a renewed call for low catch rates.

Catches in 2015 were 4,400 tonnes, 10,000 tonnes in 2016 and 13,000 tonnes last year in the stewardship and sentinel cod fisheries, along with bycatch.

"The precuationary approach requires that removals from all sources must be kept at the lowest possible level until the stock clears the critical zone," she said in a briefing presented in St. John's.

Sigrid Kuehnemund of the World Wildlife Fund's ocean's program said more data is needed to provide an accurate picture of the stock health.

"DFO has to be precautionary ... and the information DFO science has about the stock shows these declines, so you would expect to see an associated decline in fishing rates," she said from St. John's.

The latest estimates are a blow to fishermen who have watched with anticipation as scientists have tracked slow, gradual improvements in the stock health over the last decade.

A federal report last year said cod stocks continued to grow, but were still in the critical zone. It also warned that catches should be kept to the lowest possible levels for now as a precaution.

The report immediately prompted the union representing fishermen and plant workers to push for an expansion of the relatively small commercial cod fishery, saying it would not stunt the growth.

At the time, Dwyer said that while total biomass was up seven per cent from 2015 to 2016, stocks were still well below what would be needed to sustain larger-scale fishing.

Dwyer said people should not lose hope for the recovery of the fishery despite the latest findings.

"I would reiterate caution and patience," she added.

The commercial fishery was placed under a moratorium in 1992, a move that threw thousands of people out of work and sparked angry protests.

The moratorium was initially to last two years, but stocks have been slow to rebound. A fishery that had sustained the island and its outports for more than 400 years had collapsed due to a combination of factors including mismanagement, overfishing and climate change.