Cost-benefit analysis of Atlantic salmon smolt releases in relation to life-history variation

Cost-benefit analysis was applied to estimate the net present value (NPV) of Atlantic salmon (Salmo salar, Carl Linnaeus) hatchery smolt releases and the spatial distribution of the present value of benefit [PV(B)] in the Baltic Sea. The benefit was assessed for the commercial fishery and separately from hatchery-reared and wild smolts. Data on Carlin tagging and on the proportions of individual salmon stocks in the commercial catches were used. The NPV of hatchery smolt releases appeared to be negative with current rearing costs and the range of applied discount rates (2-4%), and especially with the currently low overall survival of salmon smolts in the sea (<2%). A 5% recapture rate had been needed for a positive outcome. The PV(B) of wild salmon smolts was higher than that of reared salmon smolts due to their larger catch size and higher recapture rate. Both wild and reared salmon mostly benefited the fishermen operating in the Baltic Main Basin, while few fish and minor revenues were left for the coastal and river fisheries in the Bothnian Bay. Six salmon stocks, three wild and three reared, originating from the Bothnian Bay accounted for 60% of the total Atlantic salmon catch in the Baltic Sea. The current economical benefits from hatchery smolt releases to professional fishermen barely overcome the costs they cause to rearing and releasing counterparties.