International eel symposium, 2003 - Quebec August 11, 2003
Oral Presentation

Determining Release Locations for Upstream Migrating Juvenile American Eels (Anguilla rostrata) Exiting an Eel Ladder

McGrath, Kevin* New York Power Authority, 123 Main St. White Plains, NY 10601, USA
Verdon, R. Hydro-Quebec, 75, boul. Rene-Levesque ouest, Montreal, Quebec, Canada H2A 1A4
Desrochers, D. Milieu, Inc. 1435 Chemin de Saint-Jean, LaPrairie, Quebec, Canada J5R 2L8
Fleury, C. Milieu, inc. 1435 Chemin de Saint-Jean, LaPrairie, Quebec, Canada J5R 2L8
Ault, S. Kleinschmidt, 2 East Main Street, Strasburg, PA 17579, USA
Skalski, J. Univ. of Washington, 1325 Fourth Avenue, Seattle, WA 98101, USA

Presenter email address: mcgrath.k AT nypa.gov

Abstract Text: Upstream eel passage is planned at Moses Power Dam (MPD) Massena, NY and Beauharnois Power Dam (BPD), Montreal, Quebec, on the St. Lawrence River. In preparation, mark-recapture studies were conducted to determine optimum upstream release locations to minimize turbine entrainment after eels exit a ladder. Eels (4,400) were tagged and released in equal proportions at six locations upstream of the MPD. Eels released >295 m upstream exhibited a return rate to the tailrace of <7% while those released <295 m had a substantially higher return rate, approximately 50%. On the west side of BPD 9,822 marked eels were released in equal proportions at 0 m, 90 m and 1,600 m upstream. Return rates were 4.5%, 5.0% and 3.2%, respectively. On the east side of BPD 16,697 marked eels were released at the same respective distances. Return rates were12.0%, 4.2% and 1.1%, respectively. The return rates of eels released close to the two dams were substantially different, approximately 50% vs. 5%, even though the dams are similar in size and flow. Additionally the return rates differed at each side of BPD (5% vs. 12%). These differences indicate that optimum release locations to minimize entrainment are site specific.