Work package 2.
Regime shifts, climate changes, genetic changes due to fishing, and suspected misreporting historically.
There are several issues that could give rise to problems in the meta-analysis we intend to embark on in the current project. These are: regime shifts, climate changes, evolutionary/genetic changes due to fishing, misreporting of commercial landings and discards, and changes in exploitation pattern not fully accounted for by the “common currency” F measure we will develop. This WP will outline simple and robust general “rules” for when and how to take these issues into account in the analysis in the present project. So several of the other WPs will depend of the outcome of this new package. The ICES Study Group on Precautionary Reference Points for Advice on Fishery Management (ICES 2003) provide an example of how simple and robust rules can be set up regarding the so called stock-recruitment (SR) relationship for fish stocks. By outlining types of SR-relationship observed in fish stocks, “rules” was decided upon in relation to which SR model to use and how to determine the biological reference point called Blim, which is the stock biomass value, below which recruitment is impaired. In case of a new stock, the task was then just to identify the right “type” and then the rules will give which model to use. These rules have proven to be robust and are still used by ICES. The “rules”-table is given below: