American Eel (Anguilla rostrata)

Fish of the Mississippi River

Introduction

This Mississippi River resident hatches in the Sargasso Sea--which is located well off the southeast coast of the United States, then drifts on ocean currents to the Mississippi River delta, males remain in the brackish waters of the estuary. Females continue upstream, as far north as our park, to live in freshwater rivers. As a mature adult, it returns to the ocean where it spawns and dies. It is the American eel, the long-distance champion of the fishes living here.

Scientists are still unraveling its complex life history. Some consider the highly adaptive eel to have the broadest diversity of habitats of any fish species in the world. This diversity exposes the eel to varied threats in each stage of its life, from degradation of habitat to mortality in hydropower turbines to overharvest, especially in younger life phases. Throughout its life, the eel changes color, size and physiology to suit the demands of that stage of its life.

Eels can even absorb oxygen through their skin and gills, allowing them to travel over land, particularly wet grass or mud. This behavior provides a chance to feast on unwary frogs and worms. When upset, eels can cover their bodies in a heavy, white mucous that makes them “as slippery as an eel.”

Fascinating Facts

• The eel makes chirping or slurping sounds can be heard on warm summer evenings near low bottomlands.
• All the eels in Minnesota are female. Male eels live in the brackish water of coastal estuaries.
• In 2017, the MN DNR found an American eel in Cottonwood Lake, 30 miles upstream from the confluence of the Minnesota and Yellow Medicine River.
• American eels are catadromous, meaning they spawn in saltwater and live in freshwater. This is the opposite of salmon which spawn in freshwater and live in saltwater and are anadromous.

Identification

Key ID Features: The American eel has a long, snake-like body that is dark on top, yellow on the sides, and white underneath. It has a continuous fin that runs down its back, around its tail, and underneath its belly. Its average size is 24-36 inches and average weight is 1-3 pounds.
Present in Park: Extremely rare and only infrequently caught by anglers.
Habitat: Soft bottoms of medium to large streams
MN Status: Minnesota Species of Special Concern, due to habitat fragmentation

For Further Reading

• Dickson, Tom. 2008. The Great Minnesota Fish Book. Minneapolis,MN: University of Minnesota Press.
• US Fish and Wildlife Service. 2011. American eel Anguilla rostrata. Hadley, MA: US Fish and Wildlife Service. https://www.fws.gov/northeast/newsroom/pdf/Americaneel9.26.11.2.pdf