Estimating Stock Composition in Mixed Stock Fisheries Using Morphometric, Meristic, and Electrophoretic Characteristics

Abstract

We describe a conditional maximum likelihood procedure for estimating stock composition in a mixed-stock fishery, provided that samples can be collected from the contributing stocks in isolation from each other and that characters exist that differ significantly between stocks. The procedure presented can use discrete (electrophoretic, meristic) or continuous (morphometric) data or any combination of these data. The procedure is tested by simulations and is used to estimate stock compositions of chum salmon (Oncorhynchus keta) sampled in a test fishery near Vancouver Island, B.C., in 1981. The estimated composition in the test fishery agreed closely with the results of previous tagging studies in the same area.