American eels are migratory fish that are hatched in the Atlantic Ocean and enter rivers as tiny “glass eels” each spring. The species is in decline over much of its range, and baseline studies are needed for conservation. Teams of citizen scientists collect glass eels using nets and traps in over a dozen Hudson River tributaries from Staten Island to Troy. Teatown educator Marie Perry explains how juvenile fish are counted, weighed and released to better upstream habitats, often above dams, and how you can help protect this critical species by joining the Eel Project as a volunteer.