In addition to these large crustaceans there are a myriad of smaller ones that live in the seas, lakes and ponds of the world. Crustaceans may lack the visual appeal of waterfowl or, for that matter, even fish, but they are key players in aquatic food webs. Planktonic crustaceans, which dominate the open water of the Great Lakes, harvest the small packets of energy which reside in single alga, bacterial or protozoan cells and use it for their own growth.
Benthic crustaceans are often both scavengers and consumers of plant life found on the lake bottom.
Collectively, these crustaceans serve as a key food source for fish, especially during their juvenile stage. Aside from their role in aquatic food webs, the largest species of crustaceans are of considerable economic importance. Lobster, shrimp and even freshwater crayfish each support important fishing industries. They are, as well, an increasingly important target for aquaculture activities. Crustaceans not only figure in our diet, they also feature in our literature.