Modeling the stochastic dynamics of the aggregate stock in collapsed fisheries: The case of the Northern cod stock

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Motivated by the evidence that many collapsed stocks have failed to recover despite the fact that fishing mortality has been reduced, or even when a moratorium is in effect, we develop a methodological approach using splines to analyze the stochastic population dynamics of fish stocks at low stock levels. Considering the aggregate Northern cod stock by way of illustration, we find that the species’ lack of recovery, despite the moratorium which still remains in force, is consistent with the hypothesis of depensatory population dynamics at low population sizes, as opposed to the compensation estimated by the conventional regression methods used in classic bioeconomic models.
We are grateful to Noel Roy, Peter Shelton, and Carl Walters for their comments. We also appreciate the attention and comments of the seminar participants at the Centre for Fisheries Economics, Norwegian School of Economics (NHH), Bergen (2012), as well as the participants at the 2012 ISEE Conference, 2012 WFC Conference, and 2012 IIFET Conference.
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