Experiments to determine the ideal depths, widths, and aspects of fishway entrance designs for River Herring and American Shad
Dates
Start Date
2022-10-01
End Date
2025-09-30
Summary
Alewife and Blueback Herring, collectively known as River Herring, are diadromous species that range along the East Coast from Maine to Florida. River Herring constitute one of the oldest fisheries in North America, but have experienced dramatic declines due to the combined pressures of climate change, bycatch, habitat loss, dams, and other stream barriers. Since 2009, River Herring have been managed under the Atlantic States Marine Fisheries Commission’s (ASMFC) fisheries management plan and ASMFC’s 2017 stock assessment update indicates that River Herring remain at near historic lows on a coastwide basis. In its 2021 “At-Risk Species, Summary Report”, the USFWS Northeast Region identified River Herring as priority species indicating [...]
Summary
Alewife and Blueback Herring, collectively known as River Herring, are diadromous species that range along the East Coast from Maine to Florida. River Herring constitute one of the oldest fisheries in North America, but have experienced dramatic declines due to the combined pressures of climate change, bycatch, habitat loss, dams, and other stream barriers. Since 2009, River Herring have been managed under the Atlantic States Marine Fisheries Commission’s (ASMFC) fisheries management plan and ASMFC’s 2017 stock assessment update indicates that River Herring remain at near historic lows on a coastwide basis. In its 2021 “At-Risk Species, Summary Report”, the USFWS Northeast Region identified River Herring as priority species indicating its interest in working with partners to restore these species though assessment, research, habitat restoration and fish passage.
The USFWS and the ASMFC member states have played leading roles in implementing fish passage through culvert replacement, dam removals, and the installation of fish ladders. For low head barriers, the Denil and the steeppass are the most cost-effective and common fishway. Over 148 Denils and 92 steeppasses have been inventoried1 representing a total annual fish passage capacity of 34.2 million River Herring on the East Coast. Despite this ubiquity and importance of these small fishways to habitat restoration, the Denil and steeppass designs have not meaningfully changed since 1942 and 1962, respectively. Indeed, their capacities are often unrealized due to the related problems of entrance efficiency, attraction flow, and the nuanced behavior of small schooling species like Blueback Herring. We propose to study the integration of entrance hydraulics and alosine behavior in a Standard 4-foot Denil at the S.O. Conte Research Laboratory in Turners Falls, Massachusetts. An improved entrance design would not only enhance future fishway construction but allow stakeholders to inexpensively retrofit existing fishways and thus dramatically increased the combined fishway capacity in the Northeast Region.
Objectives:
Through hydraulic modeling and experiments with live, actively migrating Blueback Herring, Alewife, and American Shad, this study will seek to determine the ideal depths, widths, and aspects for entrances. Entrance design will be evaluated for its effect on attraction efficiency, entry rates, and passage efficiency through a Denil ladder, a common fishway on the East Coast.