Can an Eel Climb a Ladder? Inside an Adelphi Student’s Research to Save the American Eel

Andrea Ward, PhD, vice provost for research and libraries, and Master of Science in Biology student Laura Fisher are studying the effectiveness of a new eel ladder design in the Mill River watershed on Long Island.

Their research examines how American eels-an IUCN-endangered species migrating between the Sargasso Sea and freshwater rivers-navigate dams and fish passages. Currently, only 13 percent of fish passages at U.S. hydropower structures are specifically designed for eel usage.¹

We've all heard of the Bermuda Triangle-that part of the Atlantic best known for sensationalized myths about aliens, wormholes and the lost city of Atlantis. But zoom out a little, and you'll learn that this patch of ocean is just one part of the Sargasso Sea, which holds mysteries of its own.

The Sargasso Sea is a 2-million-square-mile region of the North Atlantic Ocean bounded by four circulating ocean currents, creating calm, warm and highly saline waters covered by dense mats of free-floating brown macroalgae known as Sargassum, which lend this patch of sea its name. This microalgae forms a floating tropical rainforest that provides food and refuge for ocean life from fish to sea turtles-and serves as the exclusive breeding ground for the enigma that is the American eel.

"American eels have a cool life history," said Andrea Ward, PhD, vice provost for research and libraries. "They reproduce in the Sargasso Sea and then migrate thousands of miles into rivers all along the east coast of the U.S. and Canada, where they can stay in fresh water for many years until they return to the Sargasso Sea to reproduce and die." Because it takes place in this deep sea location, no one has ever directly witnessed the eel mating process, and as yet, eels have not been bred in captivity.

Young eels drift thousands of miles on ocean currents as transparent, leaf-shaped larvae before transforming into tiny "glass eels" and making their way to the freshwater rivers, streams and estuaries of eastern North America, where they spend the majority of their lives-sometimes decades-growing slowly into yellow eels and eventually the darker adult "silver eels." Capable of breathing through their skin and even wriggling overland through wet grass to reach new waterways, American eels are remarkably adaptable, yet their populations have declined sharply in recent decades.

Researching the Effect of Man on the Eel Life Cycle

According to Dr. Ward, the American eel's unique life cycle is deeply affected by artificial dams that prevent the migration upstream, one factor which has landed them on the International Union for Conservation of Nature (IUCN) endangered species list. While fish passages installed in these dams can be an effective way for fish to traverse these barriers, only 13 percent of the passages at hydropower structures in the contiguous United States are specifically designed for eel usage, making research on eel interactions with multispecies fishways an area of particular importance.

Dr. Ward's research focuses on the fields of evolutionary biology, functional morphology and developmental biology. For the past year, she has mentored Adelphi Master of Science in Biology student Laura Fisher in monitoring the eel migration along Long Island's Mill River. Fisher's studies focus on ecology, evolution and conservation biology. Specifically, the pair is looking at the effectiveness of a new eel ladder design that was put in at Smith Pond.

About the Research

• Species studied: American eel (Anguilla rostrata)
• Location: Mill River watershed, including Hempstead Lake State Park and South Pond, Long Island, New York
• Method: Field monitoring of eel migration at the Smith Pond dam, combined with a lab-built mini fish ladder testing how modifications affect climbing success
• Presented at: Long Island Natural History Conference, February 2026; Adelphi University Scholarship and Creative Works Conference, April 2026
• Status: Ongoing

"Last year, we started looking at the number of migrating eels getting to the dam at South Pond in Hempstead Lake State Park," said Fisher.

Fisher and Dr. Ward counted more than 2,000 eels over the course of four months in 2026 reaching the most downstream dam on the Mill River, which gave us a baseline for how many are even making it that far before testing modifications to the ladder itself. This is the latest dataset in field research conducted by Dr. Ward with her students for the past three years.

"This research process has been a lot of fun because I get to do a little bit of everything-we go out in the field and check eel mops for our monitoring project, yet I still also get to work with eels in the lab and design experiments to try and explain the population dynamics we see out in the wild," she said. "This variety keeps things exciting and helps me stay well-rounded as a scientist."

Hempstead Lake, located in Hempstead Lake State Park, is a sub-watershed of the Mill River watershed, as the water from Hempstead Lake flows into the Mill River, via South Pond and Smith Pond.

Fisher created a mini fish ladder in the lab to test how modifications may aid in eel migration, and the pair is combining this testing with field observation work along the Mill River. This research, which she and Dr. Ward presented at the Long Island Natural History Conference in February 2026, examines how body size and climbing substrate influence the efficiency of vertical climbing in American eels, aiming to shed light on size-related success and potential modifications at generalized fishways.

"I wasn't always on the research track, so this master's program is my first time getting to develop a project of my own and see what that entails," Fisher said. "Hopefully I will take the tools that I gain here and go on to a PhD program where I can continue researching cool animals and finding new ways to protect their populations."

In the summer of 2026, Fisher studied with the University of Washington's Friday Harbor Laboratories on San Juan Island, a highly selective summer intensive that uses the diverse marine fish community of the San Juan Islands, north of Puget Sound, as a tool for exploring the relationship between functional morphology and ecology. It has historically held a strong place in training functional morphology researchers. Fisher learned about the opportunity from Dr. Ward, who herself took a course at Friday Harbor Laboratories when she was in graduate school.

"I applied for the Functional Morphology and Ecology of Marine Fishes course and was invited to enroll, which is really exciting because this work will be highly influential in both my master's thesis work and in applying for PhD programs this fall," Fisher said. "It was great to practice field techniques for working with marine fish, learn new technologies for morphological analysis and meet other scientists interested in aquatic functional morphology."

This research has implications for the survival of a species. "Our goal in this work is to increase the migratory efficiency of eels of all sizes," said Dr. Ward. "If more eels are able to successfully move into fresh water, the result will be a larger population reproducing in the Sargasso Sea."

Research Mentorship at Adelphi

Fisher majored in both biology and dance as an undergraduate at Muhlenberg College, and she views this academic combination as an asset.

"As a dancer, I have always had an innate connection with anatomy and how the body moves, and as I progressed through my education in biology I realized this translated into an interest for how animals have evolved to physically interact with their environments," Fisher said.

In fact, when exploring graduate programs, her combined passions are what helped her find Dr. Ward, and ultimately to apply to graduate studies at Adelphi. Dr. Ward also has a lifelong passion for dance, and developed and at one time taught Adelphi's Anatomy of Dance class, helping Adelphi dancers fine-tune their performances by understanding the capabilities and limits of their bodies by incorporating science disciplines like biology and physics.

A scholarly collaborator of Dr. Ward connected the pair, and the research mentorship was born. "Finding a scientist who was doing aquatic functional morphology research while also teaching anatomy courses for dancers was really exciting to me," said Fisher.

Resources to support student research abound at Adelphi. From the SPARK Center, which promotes access for undergraduate research from day one, to graduate and doctoral research, Adelphi students are challenged to ask questions and solve problems.

¹ Matson, P. G., Bozeman, B. B., DeRolph, C. R., et al. (2025). A census of fish passage facilities at US hydropower developments across the conterminous United States. Journal of Environmental Management, 391, Article 126623. https://doi.org/10.1016/j.jenvman.2025.126623