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

Abstract

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 achieved by estimating conversion coefficients between the two vessels through an intercalibration experiment. This paper describes such an experiment conducted from two French research vessels, including (i) a review of previous intercalibration experiments; (ii) a statistical model based on quasi-likelihood functions yielding conversion coefficient estimators; (iii) a simulation approach using both the model and previous survey data to plan the experiment; and (iv) a bootstrap procedure providing robust estimates of the conversion coefficients obtained from the model.