Saving Seafood

Are harp seals responsible for the stalled recovery of Atlantic cod?

December 2, 2025 — In June 2024, the Canadian government lifted the moratorium on northern cod fishing in Newfoundland and Labrador after 32 years. The decision was controversial because cod numbers had not recovered since they collapsed in the early 1990s.

The collapse of Atlantic cod stocks in Newfoundland and Labrador had a huge impact on the economic and social fabric of the province. The subsequent fishing moratorium in 1992 put nearly 30,000 people in the province out of work.

Several explanations have been put forward for the stalled cod recovery, including environmental conditions, historical overfishing and prey availability.

Another explanation has identified predation by harp seals as the reason cod numbers have remained low. However, given the severity of historical overfishing that occurred, Atlantic cod population growth may be impaired by a number of factors.

The Northwest Atlantic harp seal population was estimated at 4.4 million in 2024, the second-largest seal population in the world. Fishermen have long been concerned about the amount of fish that harp seals consume. However, a 2014 Fisheries and Oceans Canada study concluded that harp seals do not strongly impact the northern cod stock.

The concerns of fishermen about the impact of seals on fish stocks were heard by the Canadian government. In September 2023, the Department of Fisheries and Oceans announced funding for independent seal science. It was through this funding opportunity that I recruited postdoctoral fellow Pablo Vajas and MSc student Hannah West to dive deeper into the issue.

Read the full article at The Conversation

The Northern Cod Quota Increase – a risky decision or a precautionary approach?

November 21, 2025 — Earlier this year, the Canadian Department of Fisheries and Oceans (DFO) doubled the total allowable catch (TAC) in the Northern cod fishery off Newfoundland and Labrador. This is the same fishery that infamously collapsed and was officially closed to all commercial fishing activity in 1992. The DFO’s decision has, unsurprisingly, been very controversial.

For this post, we spoke to several experts to understand the decision-making process that reopened this fishery and increased the TAC for the upcoming season. We learned that the assessment process has evolved during the moratorium, incorporating more ecosystem considerations, such as capelin, a major food source for Northern cod. Other environmental factors may have hindered cod’s recovery, however. Some stakeholders seriously challenge the appropriateness of the reference points used to assess the population. There is wide disagreement on what a successful Northern cod fishery should look like in 2025 and beyond.

History of Northern cod

Northern cod landings surged significantly in the 1960s after European factory trawlers were introduced, enhancing fishing efficiency and catch volume. Before 1976, Canada could not enforce a 200-mile exclusive economic zone like it does now, so the cod fishery was practically open access. In 1968, catch peaked at 810,000 metric tons – roughly three times higher than the average annual catch in the 1950s.

10 years later, by 1978, the annual catch had plummeted to 138,500 metric tons. A brief rebound in the mid-1980s was followed by a population crash in the early 1990s.

Dr. Jake Rice, DFO’s chief scientist for nearly three decades and now emeritus, began his career studying terrestrial food webs before joining DFO in 1982 to study Northern cod. He was promoted to director of peer review and science advice for all of Canada’s fisheries in 1997. He spoke with us about the years before the moratorium:

Rice:

The first warnings came in the 1985-1986 stock assessments. Trends seemed to be heading in a different direction than expected, but we couldn’t explain why. The offshore fishery was skyrocketing, while the inshore fishery was having some of the worst summers in a generation. It became political and controversial. A review team, chaired by the late Dr. Lee Alverson, was appointed for further evaluation.

By 1990, we were more certain of the downward trend but still struggling to account for why it was happening. Foreign overfishing was the first boogeyman, but that theory was debunked after effective patrols proved this couldn’t be the primary cause. Next, it was seal predation, then it was discarding and underreporting. Every possible cause was considered.

Read the full article at Sustainable Fisheries UW

Study: Gulf of Maine warming faster than thought

January 19, 2016 — The news just keeps getting worse for cold-temperature fish such as cod in the ever-warming waters of the Gulf of Maine.

A new study, conducted by National Oceanic and Atmospheric Administration researchers and appearing in the Journal of Geophysical Research — Oceans, reached an ominous conclusion: the waters of the Gulf of Maine, which a previous study showed to be warming faster than 99.9 percent of the rest of the planet’s oceans, are continuing to warm at an accelerated rate and are expected to continue doing so for at least the next 80 years.

“The Gulf of Maine is really being subjected to a one-two punch,” said Vincent Saba, a NOAA Fisheries scientist and lead author of the study. “On one hand, the region is dealing with the elements of global warming being experienced in all of the oceans, but there also has been a change in the circulation of the two gulf streams that feed into the Gulf of Maine.”

The result, according to Saba, is that more of the warmer water contained in the shifting Gulf Stream is making its way into the Gulf of Maine from the south, while less of the colder water from the Arctic and Labrador streams are entering the gulf from the north and east.

“The Gulf of Maine really sits at the intersection of those two currents,” Saba said.

Saba said the climatic models used in the study project the warming trend could continue for the next 80 years, potentially rising another 4 to 7 degrees Fahrenheit and setting the stage for extreme and potentially ruinous changes in the region’s ecosystem.

Read the full story at The Salem News

Scientists: Warming Ocean Factor in Collapse of Cod Fishery

October 29, 2015 — PORTLAND, Maine (AP) — The rapid warming of waters off New England is a key factor in the collapse of the region’s cod fishery, and changes to the species’ management are needed to save one of America’s oldest industries, according to a report published Thursday in Science magazine.

Fishery managers say cod spawning in the Gulf of Maine — a key fishing area between Cape Cod and Canada that touches Massachusetts, Maine and New Hampshire — is only about 3 percent of sustainable levels, and participants in the fishery that dates to the Colonial era face dramatic quota cuts as a result.

The scientists behind the Science report say the warming of the Gulf of Maine, which accelerated from 2004 to 2013, reduced cod’s capacity to rebound from fishing pressure. The report gives credence to the idea — supported by advocacy groups, fishing managers and even some fishermen — that climate change has played a role in cod’s collapse.

The lead author of the study, Andrew Pershing of the Gulf of Maine Research Institute in Portland, said the gulf is warming at a rate 99 percent faster than anywhere else in the world, and as a result, too many of the fish aren’t living past age 4 or 5. Cod can live to be older than 20.

“Every animal has a temperature range that they prefer. The Gulf of Maine, for cod, is really at the warm end of that,” Pershing said. “If you warm it, you push it somewhere that’s really uncomfortable.”

Read the full story from the Associated Press at The New York Times

Cod Could Recover in Warming Waters

October 28, 2015 — The first clue came in 2008, recalled George Rose, a marine biologist at Memorial University of Newfoundland, when he saw the cod aggregating in large numbers offshore during the spawning season. It was a sight he had sorely missed in 15 years. In the early 1990s, cod fisheries suffered such a dramatic collapse that they emerged as an aquatic poster child for fisheries mismanagement, according to Rose.

In a paper published yesterday in the Canadian Journal of Fisheries and Aquatic Sciences, Rose and his colleague, Sherrylynn Rowe, document the comeback of the Atlantic cod off Newfoundland and Labrador over the past decade. The fact that they have shown that the cod stock there is on the way to recovery is good news, Rose said, as “it shows that it is not all gloom and doom.”

Their study attributed the recovery to improved environmental conditions, better fish management and the availability of an important food source, capelin, whose populations also fell drastically in the early 1990s and have recently bounced back, too. The rebound of Atlantic cod in this region contrasts with their rapidly declining populations off the northeastern coast of the United States, where until last year the stocks remained significantly below sustainable levels. Previous research has associated this persistent population slump with the pressures of overfishing and also warming waters. The warming temperatures, however, seem to be favoring a cod fishery revival in Newfoundland and Labrador, or at least not hampering its recovery.

Read the full story at Scientific American 

 

The Great Northern Cod Comeback

October 27, 2015 — Once an icon of overfishing, mismanagement, and stock decline, the northern Atlantic cod is showing signs of recovery according to new research published today in the Canadian Journal of Fisheries and Aquatic Sciences.

This research, led by Dr. George Rose, tracks what is arguably the most important comeback of any fish stock worldwide. Studying the great northern Atlantic cod stock complex off Newfoundland and Labrador, once considered among the largest cod stocks in the world before its disastrous decline in the 1990s, Dr. Rose documents the stock’s rebound over the past decade from tens of thousands to several hundred thousand tonnes and growing.

Read the full story at Science Codex