Risk analysis and biological knowledge

Abstract

The paper adresses the question whether we fully utilize the growth in biological knowledge in fish stock assessments and risk analyses. For illustrative purposes, repeated references are made to the assessment of the Northeast 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 detennining mortality, growth and recruitment. Independent 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 properly worked up and used for testing proposed relationships. Utilizing information on the state of the system, parts of the range of variation in vital parameters can be excluded in short and medium term predictions. This would increase the empirical or informative content of our risk assessments.