Five centuries of cod catches in Eastern Canada

Rebecca Schijns,Daniel Pauly,Rainer Froese,Jeffrey A Hutchings,Sasa Raicevich

doi:10.1093/icesjms/fsab153

Abstract

Abstract The fishery for Northern Atlantic cod (Gadus morhua) off Newfoundland and Labrador, Eastern Canada, presents the most spectacular case of an exploited stock crashed in a few decades by an industrial bottom trawl fishery under a seemingly sophisticated management regime after half a millennium of sustainable fishing. The fishery, which had generated annual catches of 100000 to 200000 tonnes from the beginning of the 16th century to the 1950s, peaked in 1968 at 810000 tonnes, followed by a devastating collapse and closure 24 years later. Since then, stock recovery may have been hindered by premature openings, with vessels targeting the remains of the cod population. Previous research paid little attention towards using multicentury time series to inform sustainable catches and recovery plans. Here, we show that a simple stock assessment model can be used to model the cod population trajectory for the entire period from 1508 to 2019 for which catch estimates are available. The model suggests that if fishing effort and mortality had been stabilized in the 1980s, precautionary annual yields of about 200000 tonnes could have been sustained. Our analysis demonstrates the value of incorporating prior knowledge to counteract shifting baseline effects on reference points and contemporary perceptions of historical stock status.

Highlights

The biodiversity of the ocean has supported preindustrial fisheries, they were already capable of extirpating accessible animals (Jackson et al, 2001)
Of fish populations earlier depleted by overfishing. This is best illustrated by the Northern cod of Eastern Canada, i.e. Atlantic cod (Gadus morhua)
Ignoring the past can lead to shifting baseline syndrome (Pauly, 1995), where we accept as baseline, a situation that does not account for the previous exploitation and its impact on stock size and dynamics

Summary

Introduction

The biodiversity of the ocean has supported preindustrial fisheries, they were already capable of extirpating accessible animals (Jackson et al, 2001). Of fish populations earlier depleted by overfishing This is best illustrated by the Northern cod of Eastern Canada, i.e. Atlantic cod (Gadus morhua). The moratorium on directed commercial fishing was initially predicted by DFO to last two years to allow for sufficient stock recovery (Hutchings et al, 1997) Other factors such as temperature and prey availability may have contributed additional pressure on the stock’s ability to recover (Rose and O’Driscoll, 2002; Buren et al, 2014). Ignoring the past can lead to shifting baseline syndrome (Pauly, 1995), where we accept as baseline, a situation that does not account for the previous exploitation and its impact on stock size and dynamics This can lead to underestimating fishing impacts and setting quotas too high, preventing a stock from rebuilding (Hutchings and Rangeley, 2011). The case study presented here has two goals: (i) to demonstrate the usefulness of a 500+ year record of Northern cod catches for the current setting of stock rebuilding targets and (ii) to demonstrate, using the newly developed CMSY stock assessment method (Froese et al, 2017), that considering long time series does not necessarily require complex models with a multitude of free parameters

Methods

Conclusion

Findings

Data availability statement