Northern cod comeback

George A. Rose,* Sherrylynn Rowe

Centre for Fisheries Ecosystems Research, Fisheries and Marine Institute, Memorial University of Newfoundland, St. John’s, NL A1C 5R3, Canada.

Corresponding author: George A. Rose (e-mail: George A. Rose (e-mail: k2gr@mun. ca ). *Present address: 4843 Cutlass Crt., Pender Island, BC V0N 2M2 Canada.

Received July 19, 2015. Accepted October 1, 2015.

Canadian Journal of Fisheries and Aquatic Sciences, 2015, 72(12): 1789-1798, https://doi.org/10.1139/cjfas-2015-0346

In this paper Top of page Introduction Methods Results Discussion References Abstract The great “northern” cod (Gadus morhua) stock, formerly among the world’s largest and the icon for depletion and supposed nonrecovery of marine fishes, is making a major comeback after nearly two decades of attrition and fishery moratorium. Using acoustic-trawl surveys of the main prespawning and spawning components of the stock, we show that biomass has increased from tens of thousands of tonnes to >200 thousand tonnes within the last decade. The increase was signalled by massive schooling behaviour in late winter first observed in 2008 in the southern range of the stock (Bonavista Corridor) after an absence for 15 years, perhaps spurred by immigration. Increases in size composition and fish condition and apparent declines in mortality followed, leading to growth rates approaching 30% per annum. In the spring of 2015, large increases in cod abundance and size composition were observed for the first time since the moratorium in the more northerly spawning groups of this stock complex. The cod rebound has paralleled increases in the abundance of capelin (Mallotus villosus), whose abundance declined rapidly in the cold early 1990s but has recently increased during a period of warm ocean temperatures. With continued growth in the capelin stock and frugal management (low fishing mortality), this stock could rebuild, perhaps within less than a decade, to historical levels of sustainable yield. More generally, if this stock can recover, the potential exists for recovery of many other depleted stocks worldwide.

Acknowledgements We thank the crews of the many research cruises that underpin this work, conducted by DFO, the Natural Sciences and Engineering Research Council of Canada (NSERC) Fisheries Conservation Chair (FCC) (funded by the former Fisheries Products International, DFO, NSERC, and the Newfoundland and Labrador Department of Fisheries and Aquaculture (DFA)), and the Centre for Fisheries Ecosystems Research (CFER) at the Fisheries and Marine Institute, Memorial University of Newfoundland (funded by the DFA and the Research and Development Corporation of Newfoundland). Funding was received from the above and NSERC Discovery grants to G.A. Rose. In particular, we thank Dan Porter (DFO) and Wade Hiscock (FCC and CFER) for work at sea over the past two and a half decades.

In this paper Top of page Introduction Methods Results Discussion References

References