MASSENA — Researchers have begun a five-month study to see if light can be used to guide eels into collection points so they can be captured and transported around hydropower dams.

The study, managed by the Electric Power Research Institute, Palo Alto, California, includes a 708-foot floating boom deployed upstream from the Iroquois Dam on the St. Lawrence River between Ogdensburg and Massena. The booms are secured in place with anchors and cables extending upstream and downstream of the structure.

Lights are attached to the boom and angled toward the water with shrouds to limit above-water light emissions. Eel behavior in response to the lights is observed using implanted telemetry tags and receivers upstream of the dam, according to the institute.

The study aims to help eels navigate around two hydroelectric power stations on the river, the Robert Moses-Robert H. Saunders Power Dam at Massena and Cornwall, Ontario, and the Beauharnois Generating Station at Beauharnois, Quebec, as the eels attempt to complete their spawning migration to the Sargasso Sea in the Atlantic Ocean.

The American eel is presently listed as endangered by the province of Ontario and is considered a “species of concern” in Canada and the United States.

Previous studies have found a substantially reduced number of eels making the passage through hydropower dams on the St. Lawrence River to the Atlantic Ocean, along with a cumulative estimated turbine mortality rate approaching 40%, according to a report prepared by the Eel Passage Research Center.

The center, which was created in 2013 through funding provided by Ontario Power Generation, Hydro-Québec (HQ), the Fish Enhancement, Mitigation, and Research Fund administered by the U.S. Fish and Wildlife Service, and Duke Energy (Duke), attempts to address the challenge of providing safe downstream passage of outmigrating adult American eel.

The $24 million Fish Enhancement, Mitigation, and Research Fund was established as part of the relicensing agreement for the New York Power Authority for the Moses-Saunders Dam, with $8 million dedicated to eels.

The report indicates that the upstream passage for juvenile eels is not particularly problematic, as eel ladders, such as those created by NYPA at the Moses-Saunders Dam have been put in place to allow the juveniles to evade the dam’s turbines. The downstream passage of adult eels has proven more problematic, leading to substantial research into efforts to mitigate the high rate of turbine mortality.

Currently, the most effective method of reducing turbine mortality is to trap and transport the eels around dams. The most significant studies undertaken during NYPA’s relicensing included surface and midwater trawling for American eels on the St. Lawrence River; differentiating downstream migrating American eels from resident eels in the river; development of acoustic telemetry technologies suitable for tracking American eel movements in the vicinity of a large hydroelectric project; and an American eel light avoidance study.

The latest study, which is expected to be completed in December, will assess the ability of light to guide eels to a collection point for capture and transfer around the dams. According to the research center’s report, other studies conducted around the world have indicated that light stimulus is likely to produce effective behavioral eel guidance response in the St. Lawrence River.

In addition to Ontario Power Generation, Hydro Quebec, U.S. Fish & Wildlife Service and NYPA, project participants include the Canadian Department of Fisheries and Oceans; Quebec Ministry of Forest, Fish and Wildlife, and Parks; Ontario Ministry of Natural Resources and Forestry; New York State Department of Environmental Conservation; Carleton University; and the Natural Sciences and Engineering Research Council, with management done by the Electric Power Research Institute.