The Girnock and Baddoch catchments are long-term monitoring sites where the population dynamics of spring salmon have been assessed since 1966 and 1988 respectively. These sites include a pair of fixed traps designed to catch returning adult salmon and descending juvenile emigrants. The descending traps are whole river traps based on a modified Wolf trap, and operate on permanent weirs. They are routinely operated in both autumn and spring, providing counts of emigrant salmon. Trap protocols have been similar, although not identical, over this long period.