Consequences of past and present harvest management in a declining flyway population of common eiders Somateria mollissima

1. Harvested species population dynamics are shaped by the relative contribution of natural and harvest mortality. Natural mortality is usually not under management control, so managers must continuously adjust harvest rates to prevent overexploitation. Ideally, this requires regular assessment of the contribution of harvest to total mortality and how this affects population dynamics. 2. To assess the impact of hunting mortality on the dynamics of the rapidly declining Baltic/Wadden Sea population of common eiders Somateria mollissima we first estimated vital rates of ten study colonies over the period 1970–2015. By means of a multi-event capture-recovery model we then used the cause of death of recovered individuals to estimate proportions of adult females that died due to hunting or other causes. Finally, we adopted a stochastic matrix population modelling approach based on simulations to investigate the effect of past and present harvest regulations on changes in flyway population si...