A comparison of methods for onboard sampling of discards in commercial fishing

Two methods for onboard sampling of discards practised in UK waters are compared. The fishing gear was light trawl and the principal species caught were haddock and whiting. The quantities of fish discarded, as well as those for the market, were measured. The methods for onboard sampling of discards were carried out in parallel. Quantities discarded estimated using the two methods are compared against the measured quantities. No evidence for bias is found for either method. The results of other analyses of the data are presented, and the advantages and disadvantages of the methods discussed. A proposal is made for an approach to onboard sampling.