Managing hunted populations through sex-specific season lengths: a case of the Common Eider in the Baltic-Wadden Sea flyway population

摘要: Management of harvested wildlife populations aims to protect species from overexploitation and ultimately extinction, by regulating exploitation towards achievable sustainable levels. However, assessments impact sustainability implemented management actions on a population level are scarce. This study assesses effects changes in hunting season length imposed the Baltic-Wadden Sea Common Eider Somateria mollissima population, including differential restriction sexes. The potential these was assessed simple demographic matrix projections. Since early 1990s, this has declined at ca. 6.3 % per annum, male/female ratio among shot birds fallen 3:2 about 3:1. Concerns Denmark regarding conservation status contemporary levels resulted shortening open 44 46 days for females 13 15 males seasons 2004/2005 2011/2012 onwards, respectively. These reduced kill adult 82 %, 31 juvenile 58 55 %. observed reduction following both matched expected based seasonal distribution sexes bag prior change. Post hunters killed more males, but markedly fewer than expected. Demographic modelling female showed that would correspond an increase annual growth rate previous −6.3 −3.6 (post 2004) −1.6 2011). model also predicted full ban eiders (adults juveniles) lead positive 0.7 Taking into account conservative estimates natural variations breeding success, sex-specific regulation may potentially be effective tool halt decline eider rendering such under prevailing conditions.