Fish Passage

River herring moving up a fish ladder in Weymouth, Massachusetts. Photo courtesy of George Loring.

Hundreds of thousands of artificial barriers have been constructed along the Atlantic coast to impound and redirect water for irrigation, flood control, electricity, recreation, drinking water, and transportation—all altering the natural features of rivers and streams. Fisheries managers and scientists, stakeholders, and the public at large have become increasingly concerned about the effects of barriers on fish and other aquatic species. Many barriers are obsolete and no longer serve their original purpose. These barriers often create impediments to fish migration, which is fundamental to the life history of diadromous species. As a result, some fish populations have significantly declined over their historical range.

The Commission is particularly concerned about the migrations of Atlantic sturgeon, American shad, hickory shad, alewife, blueback herring, and striped bass to their spawning habitat, as well as access to the long-term growth areas for American eel. Without access to these habitats, it will be very difficult to restore populations of these very important diadromous species.

In response to the growing recognition of and concerns about barrier impacts on diadromous species, the Commission organized the Workshop on Fish Passage Issues Impacting Atlantic Coast States in April 2008. The workshop consisted of presentations and discussions by fish passage experts on common designs for fish passage, experiences with the Federal Energy Regulatory Commission’s (FERC) hydropower dam relicensing process, experiences with fish passage and dam removal at non-hydropower dams, and case studies dealing with fish passage.

The Commission’s Interstate Fisheries Management Program (ISFMP) Policy Board developed tasks based on recommendations from the workshop participants to address issues affecting passage of diadromous species. The tasks include:

Develop a policy on passage efficiency for diadromous fishes
Prioritize fish passage projects
Identify effective fish passage approaches
Recommend targets for increasing fish passage in each state
Initiate an East Coast Fish Passage Plan
Develop guidance for navigating the FERC dam relicensing process
Task diadromous species technical committees with evaluating positive and negative consequences of providing fish passage

Policy on Passage Efficiency for Diadromous Species

Fish passage provided for ASMFC-managed species must be safe (non-injurious), timely (without undue delay), and effective. “Effective” means the technical approach is accepted by fish passage experts to be reasonable for the specific application. The primary objective is to pass as many upstream migrants as needed to support natural reproduction of anadromous species and colonization of nursery habitat (for eels). The most effective method is barrier removal. When removal is not feasible, parties must work together to develop fish passage using state-of-the-art technologies that will support restoration plans based on upstream habitat. It is recognized that (1) the percentage of migrants passed at each site will vary based upon watershed-specific factors including: location within the watershed, species, stream discharge, population size, and distribution of required habitat; (2) technical knowledge on effective passage designs is more advanced for some species than others, (3) all parties should commit to continued improvement of passage efficiency as technology advances and as site-specific information improves the understanding of restoration in the watershed.

A working group of fish passage experts from state agencies, federal agencies, and non-governmental organizations was established in 2009 to see these tasks through and improve passage of diadromous species managed by the Commission. The Fish Passage Working Group convenes as needed to discuss developments in fish passage and promote critical thinking to mitigate the negative effects of fish passage on diadromous species. Major accomplishments of these meetings include development of a policy (see sidebar) on passage efficiency for diadromous fishes and a guidance document identifying effective approaches to upstream fish passage. The Working Group’s recent efforts have focused on the unique challenges of fish passage for American eel, the only catadromous species managed by the Commission. A report outlining guidelines on upstream eelway design can be found here.

Working to restore fish passage, both upstream and downstream of barriers, is an evolving field that requires continued collaboration. Fish passage in FERC licensing and relicensing projects is a major concern of the Commission, with the Fish Passage Working Group developing a guidance document to promote the states’ involvement in these projects. The Nature Conservancy’s Northeast Aquatic Connectivity Project is being utilized by jurisdictions in the Northeast and Mid-Atlantic as a means to prioritize fish passage projects. The Fish Passage Working Group will continue monitoring the expansion of this project to the Southeast states as a potentially valuable tool to prioritize fish passage projects along the Atlantic coast.

Contacts

Jeff Kipp, Fish Passage Working Group Coordinator

Steve Gephard, Chair Fish Passage Working Group

Documents

Technical Memorandum: Federal Interagency Nature-like Fish Passage Design Guidleines for Atlantic Coast Diadromous Fishes (May 2016)

Proceedings of a Workshop on American Eel Passage Technologies (July 2013)

ASMFC Workshop on Fish Passage Issues Impacting Atlantic Coast States (April 2008):
Workshop Proceedings and Workshop Presentations

ASMFC Guidance Document on Upstream Fish Passage Technologies for Managed Species (September 2010)