Recent step-wise declines in returns of early-running salmon to the Girnock and Baddoch Burns, monitored tributaries of the River Dee (UK: Scotland)

Early-running MSW salmon (Salmo salar) (so-called "spring" salmon) are a consistent and major feature only of the rivers of the central and southern parts of the species ' European range. These fish enter rivers over the winter and spring months, as much as a year prior to spawning. Currently, the spring fisheries are dominated by maiden 2SW salmon and older fish are uncommon. Fisheries on early-running 2SW salmon are usually treated as ceasing in April or May. As an expedient, the absence of plus scale growth in the year of capture is often treated as a defining feature for the group. Grilse (lSW) do not contribute to the spring fisheries, since their return to the coast is deferred beyond May.