Hunting practices and seaduck harvesting

A study examines the potential impact of hunting on the population sizes of the northern common eider, or seaduck. Seaducks (Somateria mollissima borealis) underwent population declines in the eastern Canadian arctic throughout the 20th century. However, sparse nest count records and a lack of standardized bird surveys before the 1950s have rendered population estimates challenging. To determine the historical causes of the decline, Kathryn E. Hargan and colleagues analyzed biomarkers in bird feces preserved in pond sediment cores from 10 subartic seaduck colonies, thus reconstructing population changes throughout the 20th century. One island colony of seaducks faced no local hunting pressure; three colonies faced low-to-moderate hunting pressure; and six nesting islands experienced high hunting pressure. Changes in nitrogen isotopes and sterols in the sediment cores revealed a long-term decline in seaducks across colonies facing high hunting pressure in the early 20th century. The authors note that the latter finding reflects the nearby relocation of Inuit communities and the introduction of guns in West Greenland. In contrast, the colony located on the island with no local hunting exhibited stable nitrogen isotopes over approximately 200 years. The paleolimnological records suggest that hunting practices employed in 20th-century West Greenland and northern Canada adversely affected seaduck populations. According to the authors, current seabird monitoring practices should consider long-term population dynamics to reach informed conservation decisions.

Article #18-14057: "Multicentury perspective assessing the sustainability of the historical harvest of seaducks," by Kathryn E. Hargan et al.

MEDIA CONTACT: Jules M. Blais, University of Ottawa, CANADA; tel: 613-562-5800-6650, 613-282-0170; e-mail: jules.blais@uottawa.ca; Kathryn E. Hargan, Claremont McKenna College, CA; tel: 909-607-0970; email: kathrynhargan@gmail.com

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