Managing growth overfishing with multiannual compromise strategies

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Author: Marchal, P
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1997
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Northeast Atlantic
• Online Access: http://dx.doi.org/10.1139/f97-135; http://www.nrcresearchpress.com/doi/pdf/10.1139/f97-135

Most of the Northeast Atlantic stocks are currently fished above the biological reference points (e.g., F max ). In attempting to achieve such targets, advisers and managers have faced two main problems. First, it is impractical to (i) simultaneously maximize yields, stabilize fisheries, and safeguard stocks and (ii) optimize both short- and long-term outcomes for the industry. Second is the lack of predictability, several years ahead, in factors influencing decisions. This study addresses these twin issues by exploring the relative performances of various multiannual and compromise (or composite) management strategies. Multiannual fishing efforts are set in advance for a ``resolution'' period of several years, at the end of which they are updated. They are calculated to satisfy a prior weighted compromise amongst three criteria: (i) minimizing fishing effort variability, (ii) minimizing catch variability, and (iii) reaching a ``mobile target:'' the latter is defined with a second weighted compromise between the long-term target and the fishing effort at the beginning of the resolution period. A safe and optimal balance between all the short- and long-term fishery outcomes is found with a 5-year resolution period, during which the mobile target is split into 40-60% of the long-term target, and 60-40% of the fishing effort at the start of the resolution period, while criteria i, ii, and iii are weighted equally.