Sex-specific Atlantic salmon upstream passage and fallback at a natural cascade after dam removal

Fisheries Management and Ecology
By: , and 

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Abstract

In the Boquet River (NY, USA) a low-head dam set above a ~200-m bedrock cascade was removed in 2015. We used radio-telemetry to assess landlocked Atlantic salmon passage at the remaining cascade (2020, 2022). Across years, 52% of males (13/25) attempted cascade passage whereas females made no discernable attempts (0/11). Attempt probability increased with stream discharge and decreased with fish size, though overall passage success was low (1/36). Shallow depths—likely owing to an artificially widened channel—appear to be limiting passage. Additionally, we transported fish upstream but observed high fallback (72%) that was associated with fish size and energetic status. Following dam removal, this cascade continues to limit upstream passage resulting in increased vulnerability to angling during migratory delay. Overall, we highlight the importance of follow-up studies after dam removal, and that further modifications at this site may be required to improve passage.

Suggested Citation

Heim, K., Withers, J.L., Arden, W., Earley, L., Minkoff, D., and Castro-Santos, T., 2026, Sex-specific Atlantic salmon upstream passage and fallback at a natural cascade after dam removal: Fisheries Management and Ecology, https://doi.org/10.1111/fme.70073.

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Publication type Article
Publication Subtype Journal Article
Title Sex-specific Atlantic salmon upstream passage and fallback at a natural cascade after dam removal
Series title Fisheries Management and Ecology
DOI 10.1111/fme.70073
Edition Online First
Publication Date May 04, 2026
Year Published 2026
Language English
Publisher Wiley
Contributing office(s) Eastern Ecological Science Center
Country United Sttes
State New York
Other Geospatial Boquet River
Additional publication details