Fish Success Story: Cod Makes a Comeback

Overfishing almost wiped out the iconic species, but a new study finds that a 20-year fishing ban has led to a remarkable recovery in the population.
(Photo: John Tlumacki/'The Boston Globe' via Getty Images)
Oct 27, 2015· 2 MIN READ
Katharine Gammon has written for Nature, Wired, Discover, and Popular Science. A new mom, she lives in Santa Monica.

The cod is coming back.

The species that was for centuries a mainstay of the American and Canadian economies had virtually vanished off the Northeastern North American coast by the 1990s owing to overfishing. That led regulators in 1992 to impose a moratorium on cod fishing.

It appears to have worked.

New research shows that cod biomass has increased from the tens of tons to more than 200,000 tons within the last decade. This spring, scientists documented large increases in cod abundance and size for the first time since the moratorium in the more northerly spawning groups, according to a study published Monday in the Canadian Journal of Fisheries and Aquatic Sciences.

“Cod was historically one of the most important fish stocks in the world,” said George Rose, director of the Center for Fisheries Ecosystems Research at the University of Newfoundland in Canada and author of the new report on the cod’s recovery. “When the stocks collapsed in the 1990s, it became the icon of all the bad things we are doing to the ocean, and in many ways, it changed how we deal with our oceans worldwide.”

For hundreds of years, cod were so common—and so huge—that people reported being able to walk across their backs. Cape Cod was named after the fish, and salt cod is credited with sustaining explorers crossing the Atlantic from Spain and Iceland.

When the fishing ban took effect, cod had dwindled to 5 percent of its historic biomass. The moratorium threw 22,000 fishers and processing plant employees in more than 400 coastal communities in the United States and Canada out of work.

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The moratorium played a big part in the cod’s recovery, as did the return of the fish’s food source, according to the study.

Around the time that cod stocks crashed, a parallel collapse occurred in populations of plankton and capelin, a small smelt fish that provides sustenance for larger fish. “Capelin are the main conduit of energy, from plankton right up to the top of the food chain,” said Rose. “We still don’t know exactly why, but it was really uncertain whether cod could survive the changes at all.”

The first hint of the comeback came in 2008, when researchers saw regrouping of cod on their breeding grounds along with the return of the capelin.

The reasons for the return of the capelin are a mystery, but Rose said it pointed to the need for a more comprehensive approach to fishery management. “This is one of the most important examples why we need to understand the full ecosystem and not just the stocks of fish,” he said.

Cod’s future is still in question. Stocks are low in New England and other parts of the fish’s range where the ocean is warming. But in more northern areas, it is thriving.

He said there are indications that climate change will increase cod populations in Newfoundland and other northern regions.

But don’t expect cod on your dinner plate anytime soon. The Canadian fishing ban remains in place, and the U.S. has also tightened restrictions on cod fishing.

“Nature has kind of given us a second chance,” Rose said. “We don’t want to blow it this time.”