Stock assessment and biological knowledge: can prediction uncertainty be reduced

• Main Author: Øyvind Ulltang
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1996
• Subjects: Key words; stock assessments; biological knowledge; predictions; explanatory theories; empirical content; north-east Arctic cod; Arctic; Arctic cod
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.509.8869; http://icesjms.oxfordjournals.org/content/53/4/659.full.pdf

The paper addresses whether we fully utilise our increasing biological knowledge in fish stock assessments. For illustrative purposes, repeated references are made to the assessment of the north-east Arctic cod stock. In many cases, existing knowledge may allow us to establish relationships for predicting short or medium term changes in vital population parameters determining mortality, growth, and recruitment. Ancillary variables in such relationships, with a priori justification for being chosen, could be parameters describing the state of the fish stock in question or the state of its biological or physical environment. Long time-series of biological data exist for several stocks, and these data series should be used for testing proposed relationships. Explanatory theories should be used for making predictions not dependent on the assumption that historical patterns will be repeated, increasing the empirical or informative content of our assessments.