Northern cod reclaiming its territory

Research ship helps province get clearer picture of state of fish stocks

Published on May 24, 2014
George Rose, director of the Centre for Fisheries Ecosystems Reseach, talks to high school students along with the media about his research on the northern cod stocks aboard the vessel Celtic Explorer docked in St. John’s harbour Friday.
— Photo by Rhonda Hayward/The Telegram

After being beaten down by overfishing to a fraction of the mighty force it once was, northern cod are starting to rebuild and re-populate its traditional areas off the coasts of Newfoundland and Labra­dor.

That’s good news for a species that has shown few positive signs of recovery during the 22 years since being placed under a moratorium.

George Rose, director of the Marine Institute’s Centre for Fisheries Ecosystems Research, said the centre’s latest research shows “a strong initial rebuilding” of the northern cod along the northeast coast of the province.

“After years and years of where it was flatlined, where nothing was happening, we are seeing strong signs of rebuilding now,” Rose said.

“And what we need to do now is let it rebuild. … We have small fisheries now, and that’s OK, and we’ll probably continue with that, and maybe see some expansion of it, but the worst thing we could do would be to go at it too soon, too heavily, because then we might nip it in the bud. Nature has given us a second chance here and we should take it.”

Rose and his team recently completed this year’s survey work aboard the Celtic Explorer, a state-of-the-art research vessel based in Galway, Ireland. The vessel is the most sophisticated purpose-built vessel ever used for fisheries science research in the province.

In addition to northern cod, Rose’s team has been doing research on other species, including shrimp. The shrimp resource off the province has been in decline in recent years.

“We wanted to look at (shrimp) in an area called the Triangle on the north cape of the Grand Banks, and what we found was really quite intriguing,” Rose said.

“Because that area, only three years ago, was absolutely loaded with shrimp and that’s where a lot of the commercial boats were. There were no cod there. Now we go back three years later and the whole situation has changed. There are very few shrimp there and juvenile cod, small codfish — these are two and three years old — are numerous. So, we’ve seen a complete change in that ecosystem in only three years. So that’s going to have major, major implications for all of our fisheries down the line.”

Rose said what scientists think may be happening in that area is that the juvenile cod are the offspring of a strong spawning stock in an area known as the Bonavista Corridor, which are moving in as the shrimp are declining.

“And, basically, the thing behind it is the changing ocean conditions,” Rose said. “It’s hard to sell the argument this year that we are in a warming trend, because everyone knows here it’s been freezing cold and ice and so on. But overall, we are still in a warming trend, and that overall trend is probably driving this from the bottom up.”

While cod do eat shrimp, it is not their preferred source of food. Rose said caplin are what has sustained major cod stocks off Newfoundland and Labrador’s coasts for hundreds of years.

“What they want is caplin. And caplin have been scarce for 20 years,” Rose said.

“And that’s the other thing we do with our acoustic research. We work on caplin, as well. What we are seeing is what looks to be a fairly large increase in caplin this year, and the cod are all over it. They are full of caplin. They are feeding well. They are in excellent condition, which they weren’t if you want to go back 10 years.”

Rose noted it’s the centre’s fourth year using the Celtic Explorer, and they are gaining valuable information on the dynamics of the fish stocks off the province’s coasts.

Some of the work includes satellite tagging of large codfish.

“These tags are put on a fish and they stay on a fish for a year, and they pop up and they give us data on where that fish has gone, and also what temperature and depth it’s been at for a full year,” Rose said. “And so we’ve learned a couple of really interesting things about where they go when they spawn, and what their seasonal migration patterns are and how long they are staying inshore.

“And on the northeast coast, for example, their migration patterns seemed to have changed considerably from what we knew historically. The migration inshore is taking place later and they are staying inshore a lot longer, some of them into January. So, this has major, major impacts on how we interpret survey data, and also on our basic understanding of stock structure and rebuilding.”

See video of tour of Celtic Explorer at