MARK-RECAPTURE ESTIMATION OF A SALMON SMOLT POPULATION

A mark-recapture experiment was conducted applying a two-sample strati fied technique to estimate the number of Atlantic salmon smelts, Salmo salar, migrating out of the Conne River, Newfoundland. We developed a model where parameters are introduced to describe the mean time for t he salmon to migrate between the release site and recapture site and t o describe the probability of capture on a particular date. The latter are then used to expand the number of untagged smelts captured to est imate the daily run sizes. We discuss the advantages of this new appro ach over other models. For example, this formulation allows great flex ibility in the experimental design, is robust to violations of assumpt ions, and allows the influence of environmental factors upon the param eters to be investigated.