Double-crested Cormorants: Perceived as Invaders

Much of the conflict between cormorants and humans on the Great Lakes stems from the mistaken assumption by many people that the cormorant is a non-native intruder to the area.  Cormorants historically had a presence on the lakes in numbers that may have even exceeded the numbers we see there today. Even as late as the mid-1950s many double-crested cormorants nested on Great Lakes islands. As the effects of persecution and DDT progressed, cormorant numbers declined sharply. And as cormorants declined for several decades, human collective memory of their presence and nesting colonies declined as well. Generations of Great Lakes commercial, charter, and recreational fishermen simply forgot about cormorants and the role they had played in the lakes environment.

The EPA banned DDT in 1972, giving double-crested cormorants an appeal from extinction as their thin-shelled eggs again became viable. Feeding primarily on the plentiful alewives and round gobies, the true invasive species, cormorant numbers increased exponentially. New generations of fishermen, unfamiliar with the cormorant’s history on the lakes, considered re-colonizing cormorants exotic thieves stealing what belonged to them alone -- the fish. To anglers the situation was intolerable. The guns came out, cocked and ready to fire.