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Community Science: The Hudson River Eel Project

Students and Community Partners Research Migratory Fish

Watch a video clip about the eel project

The American eel (Anguilla rostrata), a migratory fish, is born in the Atlantic Ocean and enters North American estuaries, including the Hudson River, as tiny, see-through "glass eels" each spring. Once they arrive, they soon gain pigment and become part of the ecosystem for years to come. The species is in decline over much of its range, and baseline studies, like the Hudson River Eel Project, of populations are crucial for management decisions.

Glass eels
Glass eels

The eel project is coordinated by the DEC Hudson River Estuary Program and the Hudson River National Estuarine Research Reserve, in partnership with NEIWPCC and the Water Resources Institute at Cornell University. During this project, teams of scientists, students, and volunteers collect glass eels using specialized nets and traps on Hudson River tributaries each spring. The juvenile fish are counted, weighed, and released, and other environmental data is recorded. At the end of each season the data is compiled and sent along to decision-makers.

The project directly involves students and volunteers with scientific design and field methodology. Participants experience their local ecosystem firsthand, and collect important information and relevant data about migrating fish.

Volunteer With Us

There are many opportunities to get involved with the eel project. Below are descriptions of our eel projects. Check out other volunteer opportunities with the Hudson River Estuary Program.

If you are interested in getting involved, email, and include where you live so we can find a nearby site.

With COVID-19 safety protocols in place, including limited group sizes, there may not be room to volunteer at a site near you. Please contact us and we will add you to our email list for next year.

The Projects

Fyke Nets: Large fyke nets are set in the mouths of tributaries for six to eight weeks each spring, catching the juvenile eels as they migrate upstream. Each net is checked every single day by two or more volunteers. Often, people sign up to check a net one or more specific days per week. It takes approximately an hour to sample each day. All gear and materials are provided, but personal transportation to the site is required. Volunteers should be willing to work outside under variable conditions, and work collaboratively within a team of students and volunteers.

Eel Mops: Eel mops are devices made to mimic juvenile eel habitat. They are passive traps that are set in the water and checked for living things as often or as little as needed. In addition to glass eels, we often find invertebrates and other small fish as well! Learn How to Make an Eel Mop (PDF).

Eel Ladders: On their journey upstream, eels are confronted by barriers that prevent access to favorable habitats. At a few locations by dams, we set eel ladders that catch eels attempting to swim upstream. The eels are then counted, sized, and released above the dam. The ladders are checked twice a week during the summer sampling season.

Students set a specialized eel net

Students set a specialized eel net.

Sample sites include:

  • Richmond Creek in Staten Island
  • Saw Mill River and the Center for the Urban River at Beczak in Yonkers
  • Furnace Brook in Cortlandt
  • Minisceongo Creek in West Haverstraw
  • Sparkill in Piermont
  • Indian Brook at Constitution Marsh in Cold Spring
  • Quassaick Creek in Newburgh
  • Hunters Brook in Wappingers Falls
  • Fall Kill in Poughkeepsie
  • Crum Elbow Creek in Hyde Park
  • Enderkill in Staatsburg
  • Black Creek in Esopus
  • Saw Kill in Annandale-on-Hudson
  • Hannacroix Creek in New Baltimore
  • Poestenkill in Troy

Some Eel Project History

Volunteers from the Eel Project celebrate the end of the sampling season and go over results with DEC staff

Volunteers from the Eel Project celebrate the end
of the sampling season and show results to DEC staff.

The Hudson River Eel Project began in 2008 with two sites, the Fall Kill in Poughkeepsie, and Furnace Brook in Cortlandt. By 2018 the project expanded to 14 sites, ranging from New York City to Troy, with over 750 volunteers lending a hand (and learning a thing or two). Over its lifetime, the Eel Project has caught, counted, and released over one million glass eels, helping these animals access better habitat.

Over the course of the project we have collected interesting data. In 2018, volunteers caught an average of 183 glass eels per day. This is a significant increase from the first few years of the project during which the average catch per day was around 20-30 eels. One of the key educational aspects of this project is bringing the data back to classrooms to have students interpret and learn from it.

Thank you for your support. In addition to hundreds of volunteers, the Eel Project is supported by many organizations and partners.

Please email us to find out more and sign up to volunteer.