Introduction: Double-crested Cormorants of the Great Lakes – St. Lawrence River Basin: Recent Studies, Movements and Responses to Management Actions

This paper introduces the second Special Publication of the Waterbird Society to address the biology and management of the Double-crested Cormorant (Phalacrocorax auritius) in North America. Since the late 1960s and early 1970s, when the species was at very low population levels, the Double-crested Cormorant has rebounded to its greatest population level in over 100 years. Such a significant increase has resulted in changes in community structure, and new stressors, in many aquatic ecosystems. Both Special Publications (1995 and 2013) have been focused on the biology and management of the species. The first volume dealt mainly with population growth and the resulting, immediate management issues. In the current volume, studies address the longer term situation, the implementation of two U.S. depredation orders and new research directions identified in the first Special Publication and in subsequent smaller cormorant symposia. Seventeen papers which comprise this volume are presented under six headings: introduction, impacts to natural resources, population dynamics, evaluation of control efforts, assessing fish consumption and bioenergetics, migration ecology and local and seasonal movements, and summary overview and future information needs. A second Special Publication on Double-crested Cormorants gives us an opportunity to assess how well cormorant biologists have addressed and answered questions we posed to ourselves 15 years earlier; it also provides us with a vision for the next 18 years