Monitoring American eel migration for both conservation and constituency-building in the tidal Hudson River estuary

Background/Question/Methods

As a catadromous species, the American Eel (Anguilla rostrata) migrates from the Sargasso Sea to spend the majority of its life in coastal freshwater or estuarine environments. Many eel populations have declined worldwide in recent decades, and in 2014, the IUCN declared the American Eel as an endangered species. Diadromous fish managers now face the dual challenges of protecting eel populations while educating decision-makers and the public about this species. To address both conservation and stewardship goals, researchers work with trained citizen scientists at twelve sites spanning 132 miles of the tidal Hudson River Estuary to monitor juvenile eel migration according to the Atlantic States Marine Fisheries Commission protocol. The project employs fyke nets, “eel mops”, and trap-and-pass ramps as collection gear placed along urban shorelines, tributary mouths, and below dams. Since 2008, study sites have been sampled for juvenile eels approximately every day of the spring season. Citizen science volunteers come from a wide range of demographics and backgrounds, from urban youth to college interns, and from admitted non-scientists to environmental professionals. Comprehensive volunteer training, species-selective gear, and clear collection methods help ensure a robust data set of juvenile eel numbers, timing, and basic environmental data.

Results/Conclusions

The Hudson River Eel Project has continued to yield dynamic results regarding both conservation management and constituency-building. Since the project began in 2008, volunteers have caught, counted, and released over 2,500 juvenile eels per season, mostly above upstream barriers to migration. On average, individual sites have collected as few as less than one juvenile eel per day, while others have collected over 900 juvenile eels per day throughout a single sampling season. These results speak to the complexity of factors that may be affecting eel migration, such as precipitation, water quality, and tributary location. Through partnerships with public schools, colleges, watershed alliances, and various community groups, the project successfully communicates the importance of ecological conservation to broad audiences. Additionally, the use of citizen scientists has created built-in local support at a low cost due to several thousand hours of donated time. The result has been a richer picture of eel migration along the tidal Hudson, both temporally and spatially, as well as significant public attention to eels through print and online media, classroom programs, and social networking. This project can be replicated in coastal areas from the Caribbean to Canada, effectively combining migration data collection with public awareness and stewardship.