Diagram depicting the catadromous lifecycle and migration of the American Eel, Anguilla rostrata. Beginning their lives as eggs and larvae (called leptocephalus) around the Sargasso Sea, Eels then use their Gulf Stream to migrate up the coast and into freshwater tributaries where, as Glass Eels they begin to pick up pigmentation, growing into adolescent Elvers, and then adult Yellow Eels. Mature adults go through another metamorphosis for their return breeding migration to the ocean, becoming Silver Eels. Watercolor, Beam Paints.