A Disconnect between Science and Management for Double-Crested Cormorants (Phalacrocorax auritus) in Northern Lake Michigan, USA, 2000–2016

Abstract

In 2000, studies began on the Double-crested Cormorant (Phalacrocorax auritus) in the Beaver Archipelago, Lake Michigan, Michigan, USA, and have continued through the present. Research was conducted to determine whether Double-crested Cormorants were preying on smallmouth bass (Micropterus dolomieu) and causing a decline in this fishery. Breeding Double-crested Cormorant population estimates were recorded to document population dynamics before management and throughout the intensive control program, initiated in 2007. Research included studies using telemetry, raft surveys, banding, game cameras, and development of several bioenergetics models. In addition, co-nesting species were monitored to investigate impacts of Double-crested Cormorant control on non-target species. Results indicated that Double-crested Cormorants do not negatively impact smallmouth bass populations, co-nesters or other components of the system. However, control measures were initiated and continued through 2015; litigation ended control activities in 2016. Research suggested that control led to abandonment by Double-crested Cormorants of traditional colony sites, a switch from ground to tree nesting, and impacts on co-nesting species. This review demonstrates a significant disconnect between science-based knowledge and chosen management practices. Although court rulings ceased Double-crested Cormorant control, this disconnect should be addressed and remedied; science-based knowledge should be emphasized in any future management.