SUFB 046: A Tale of Two Cod Stocks

By November 9, 2015 November 12th, 2015 Speak Up For Blue Podcast


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Speak Up For Blue Podcast

Welcome back from the weekend Speak Up For Blue crew, I missed you. We’ve got some good news to bring you today, as data out of Newfoundland suggests that the Northern cod population is starting to recover from its collapse just a few decades ago.

Let’s start with some background. Over the past few hundred years, but particularly within the last eighty, technological advances, changing climate, improper fishery management, and an increase in coastal populations led to a decimation of Atlantic cod stocks (Gadus morhua)*. That’s why in 1992 Canada imposed a moratorium on cod fishing in the North Atlantic. By continuing to heavily fish this species, we would be ensuring its extinction and a severe economic collapse for coastal fishing communities. Though the collapse of this incredibly lucrative fishery brought significant hardship on Atlantic fishing communities, the moratorium was meant to be just the first step in the long journey to recovery. Last week, a study published in The Canadian Journal of Fisheries and Aquatic Sciences suggests that this recovery may be progressing.

George Rose, Director of the Centre for Fisheries Ecosystems Research at Memorial University of Newfoundland and author of the study, claims that cod are making a “major comeback after nearly two decades of attrition and fishery moratorium.” Compared to stock biomass estimates of just a few tens of thousands of tons a decade ago, acoustic-trawl surveys indicate current cod biomass is approximately 200,000 tons. Rose believes that this increase in the cod stock is tied to a combination of factors, including the reduced fishing pressure and the return of its main prey, the capelin (Mallotus villosus). Rose stresses that this data is in no way indicative of a complete recovery of the Northern cod, and that the current population is not large enough to sustain any industrial fishery. However, it does provide strong evidence that given proper management and favorable environmental conditions, even heavily fished species can rebound.

I say favorable environmental conditions because, unfortunately, some neighboring cod stocks have not seen the same recovery. Cod populations in the Gulf of Maine are still dangerously low, primarily due to rising sea surface temperatures. This region is warming faster than 99.9% of our oceans, according to a study published in Science looking at the Gulf of Maine cod stock. Female cod give birth to less offspring when water temperatures rise, and juvenile cod are less likely to survive in warm waters compared to cooler ones. The U.S. did not account for changing environmental conditions when establishing catch quotas years back, leading to an inadvertent overfishing of cod in the Gulf of Maine. While the Northern cod up in Canada are slowly recovering, a result of strong management and lucky geography, the exact same species just a little further south is facing an entirely different and more dire set of circumstances.

*This is an oversimplification of the problem facing many Atlantic fisheries. For a history of fishing in the Atlantic going back to the dark ages, check out “The Mortal Sea” by W. Jeffrey Bolster.

Enjoy the Podcast!

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