Abstract
Research fisheries surveys are now implemented as monitoring programs of fish stocks and provide a large set of measurements on the evolution of their state. Here we show how fishery-independent diagnostics of fish stocks can be achieved using a comprehensive set of indices and analysis procedures inspired from environmental monitoring.
We present fish stock indices, analysis procedures and diagnostics results for nine stocks in European waters. The set of indices considered comprises two population abundance indices, four indices for population vital traits and nine indices for spatial organisation by age. The indices are combined and selected using multivariate techniques that maximise correlation between variables and also continuity in time. Trend detection and quality control techniques are then applied on the time series of the combined and selected indices. Based on these analyses diagnostic tables are filled, leading to comprehensive indicator-based diagnostics of fish stocks.