Intercalibration of research survey vessels in fisheries: a review and an application

Fisheries stock assessments often rely on time series of abundance indices obtained from annual research surveys. It is thus important to maintain the temporal continuity of such series when vessels change. This can be achiev ed by estimating conversion coefficients between the two vessels through an intercalibration experiment. This paper describes such an experiment condu cted from two French research vessels, including (i) a review of previous i ntercalibration experiments; (ii) a statistical model based on quasi-likeli hood functions yielding conversion coefficient estimators; (iii) a simulati on approach using both the model and previous survey data to plan the exper iment; and (iv) a bootstrap procedure providing robust estimates of the con version coefficients obtained from the model.