The American eel is a fish native to the East Coast of North America. They are born in the Western Atlantic Ocean in the Sargasso Sea, and migrate to freshwater streams and rivers (making them catadromous), a journey which can take several years and span thousands of miles. Once in these freshwater systems, they grow and mature for as long as 10 to 25 years before returning to the ocean to spawn. American eels are an economically important species and historically were heavily fished primarily for the European Market. They are still highly valuable and this, coupled with the presence of dams and other barriers to their migration, have contributed to their decline. In the Bronx River, a special feature called an eel ladder, resembling a small waterslide, was installed at River Park, to help eels climb over the historic dam and complete their migration.