Cormorant predation mortality of perch (Perca fluviatilis) in coastal and archipelago areas, northern Baltic Sea

Abstract Perch (Perca fluviatilis) is an important prey species of the great cormorant (Phalacrocorax carbo sinensis) in coastal waters northern Baltic Sea. The annual predation mortality caused by cormorants was estimated based on consumed numbers perch relation to abundance vulnerable age groups sea. We used existing stock assessment data (Archipelago Sea) or a simple population model other areas (Gulf Finland, Bothnian Sea, and Quark), commercial recreational catches, fishing natural mortalities, with distributions describing our understanding about likelihood different values for every variable. median 4–10% annually, depending sea area. area-specific 80% limits ranged from 3 21% annually. Compared recent tagging study Quark, cormorant-induced estimates were considerably lower, but partly overlapped. results sensitive number population, which turn largely depends young groups.