The double-crested cormorant (Phalacrocorax auritus) is a large (30–36 in; 73–90 cm), blackish water bird that eats fish and crustaceans. The double-crested cormorant population around the Great Lakes (but not in other areas) was once in serious decline. It has now has recovered. In fact, some fishermen feel that there are too many double-crested cormorants. These fishermen believe that an abundance of double-crested cormorants is responsible for a decline in fish populations in the Great Lakes. The conservation of this bird entails weighing the interests of the fishing industry against the interests of a now-abundant bird whose range is expanding.

The double-crested cormorant is a large migratory water bird native to North and Central America. The bird is found along the West Coast as far north as southern Alaska, wintering in Southern California and Baja California. On the East Coast it breeds from Maryland to Newfoundland, wintering along...