Cormorants are trained for fishing in several parts of the world. Usually, a restricting collar is put on their neck, which allows them to eat small fish, but keeps them from swallowing large fish. They return to the fisherman, who helps them get the large fish out of their mouth, and then they go back to hunting.

This one is a Double Crested Cormorant, in breeding colors. I photographed him on the Anhinga Trail in Everglades National Park.