The ratios of juvenile sardine to anchovy observed in the fishery and in the recruit surveys are compared against those estimated by the anchovy assessment model. Assuming the model ratio of sardine:anchovy recruit numbers represents the ‘true’ ratio, it is found that almost no reliable inference can be made about the true ratio from that observed in the fishery, (possibly because the industry take steps to avoid areas with high juvenile sardine bycatch), but that some inference is possible from the ratio observed in the survey (though this has relatively high variance).
History
Department/Unit
Department of Mathematics and Applied Mathematics, University of Cape Town