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Restoring River Herring to Improve Essential Fish Habitat for New England Groundfish

Cumulative river herring returns for the following dams in the Gulf of Maine: Cataract, Brunswick, Lockwood, Burnham, Milford, Ellsworth and Milltown.  Data through 2012 includes harvest  totals.

Location of active fishways where NOAA Fisheries Habitat Conservation staff are working.

Alewife collected at the Lockwood Project. Photo credit: Sean McDermott, NOAA Fisheries

By Sean McDermott, Greater Atlantic Regional Fisheries Office, Habitat Conservation Division

Healthy habitats are the cornerstone to sustaining resilient and thriving marine resources and communities. Fish require healthy habitat to survive and reproduce. Providing for healthy habitat to support commercial and recreational fisheries is a central goal under U.S. federal fisheries law (the Magnuson-Stevens Fisheries Conservation and Management Act). Under this law, some prey species, such as alewife and blueback herring, are actually considered part of the habitat.

When the law was amended in 1996 to require that fishery managers define Essential Fish Habitat (EFH) for all federally managed species, a major milestone was achieved in fisheries management. EFH is defined as those waters and substrate necessary for fish to spawn, breed, feed or grow to maturity.

EFH includes all types of aquatic habitat. Typically, ‘habitat’ is viewed as wetlands, cobble substrate, coral reefs, seagrasses and rivers. However, it also includes prey species as a component of the habitat. Alewife and blueback herring, also referred to as “river herring”, are important prey species for many other commercial and recreational fish species (e.g., cod, striped bass, etc.), mammals and birds of prey. Recently, river herring have generated attention in the regional media for their important role in the marine food chain.

River herring are anadromous fish. They spend most of their life cycle in the marine environment, returning every four to five years to the river where they were born to spawn These fish experience a number of natural threats, primarily predation, before completing their life cycle.

River herring also are exposed to man-induced threats such as commercial fishing, pollution, and habitat loss and degradation. One of the greatest threats to these fish are dams across rivers. Dams alter habitat conditions and prevent or inhibit the migration to and from spawning and nursery habitat. 

NOAA Fisheries staff are working with the U.S. Fish and Wildlife Service and the State of Maine, to enhance fish passage at dams and improve habitat quality in the streams river herring were born. 

Our work to install and improve fish passage at hydropower facilities in Gulf of Maine coastal rivers, along with other management activities, has resulted in some great success. Over 2 million river herring have been counted at a newly installed fish passage facility (fishway) on the first dam on the Sebasticook River, a major tributary to the Kennebec River. This is up from 400,000 fish that were captured and trucked around the dam prior to the installation of the fishway. 

Another fishway was installed and became operational this year at the first dam on the Penobscot River. Nearly 200,000 river herring were counted, up from approximately 12,000 in 2013. These growing runs of river herring return to the sea as juveniles becoming part of the EFH (food source) that supports federally managed fish such as Atlantic cod and many other species.

Our hope is that by increasing the overall population of river herring in the Gulf of Maine, this will have direct results on the stock rebuilding and sustainability of our economically and socially important New England Groundfish fish stocks.