Potential bias in multispecies sampling of purse seine catches

Abstract

This paper discusses the various potential biases associated with species and size sampling carried out in the Atlantic Ocean during landings of purse seiners. This paper is a follow- up of the 4th Meeting of the WCPFC Scientific Committee during which there were serious doubts expressed about the bias faced by the sampling schemes used in the Atlantic since 1980. The conclusion of the paper is that the sampling scheme currently used in the Atlantic appears to be consistent and satisfactory, but that minor potential biases in this sampling should be better identified and reduced by improvements in the current sampling and data processing. It is recommended that an international working group be organized to identify these uncertainties and to improve the multi-species sampling schemes and the data processing of their results.