Research Document - 2014/083

Evaluation of Compliance to the Precautionary Approach of Harvest Decision Rules for the Snow Crab (Chionoecetes opilio) Stock of the Southern Gulf of St. Lawrence

By G. Chaput and DFO/Industry Joint Working Group on Decision Rules for Snow Crab from the Southern Gulf of St. Lawrence

Abstract

This research document presents the work of a joint DFO-Industry working group tasked with developing candidate harvest strategies and decision rules for the snow crab (Chionoecetes opilio) fishery of the southern Gulf of St. Lawrence. Variants of harvest decision rules in which exploitation rate vary with stock size in the cautious zone and in the healthy zone of the Precautionary Approach (PA) framework are described. Performance of the candidate rules are assessed using a simulated time series of recruitments over 50 years that incorporates observation errors equivalent to those from the current stock assessment model. Criteria for assessing compliance of candidate harvest decision rules to the PA are presented. The primary criterion for assessing if a rule is PA compliant is for less than 5% chance of the stock falling below Blim due to fishing activities over all years in the simulation rather than a single fishing year. Examination of performance of candidate rules indicated that the harvest decision rule profile in the cautious zone was the primary determining factor for PA compliance. A total of twelve variants of harvest decision rules examined by the working group were considered to be PA compliant. The assessment of the compliance of candidate decision rules was submitted for peer review at the DFO Science peer review meeting of January 29-31, 2014. The conclusions of the science peer review of compliance of harvest decision rules to the PA are presented in the science advisory report (DFO 2014).

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