Restoring alewives, as a keystone species that connects our communities on land with the ecosystems that we depend on in the sea.
Overview
Spring in Maine means alewives, a species of river herring (Alosa pseudoharengus), are swimming from the ocean to freshwater ponds and lakes to spawn. These little fish and their yearly migration are at the center of connecting onshore communities and the marine ecosystems on which coastal Maine relies. Their Passamaquoddy name translates to “the fish that feeds all”, and rightly describes their keystone role in the marine food web. They are prey for numerous species, notably osprey, seals, eagles, and groundfish such as cod. Their presence has a cleansing effect on rivers, lakes, and ponds by maintaining a healthy balance of nutrients in the water, which also improves habitat in support of conservation of endangered species, such as Atlantic salmon.
Blue heron preying on an adult alewife. Photography credits to Jon Albrecht
Updates
The Challenge
The range of river herring spans the Atlantic seaboard from Florida to Newfoundland, and once numbered in the tens of millions in Maine’s rivers (MITSC 2023). Alewives are anadromous, meaning they travel from saltwater to freshwater and throughout their life stages are subjected to many varying barriers to their survival and reproductive success. Environmental stressors and changes such as water quality and temperature, salinity, acidity and blockages along their river migration routes such as dams, have imperiled the species’ resilience and recovery efforts are needed. Regional focus on restoration of their critical river habitat has led to significant increases in the number of active and potential river herring runs in Maine. This further bodes well for the future of Gulf of Maine fisheries, where the recovery of alewives may underpin the recovery of groundfish fisheries in the Gulf of Maine.
The Opportunity
Along with partners across the country, Maine Center for Coastal Fisheries advances research that allows us to assess the current alewife populations within the Bagaduce River, and restore alewife populations in other rivers where they have historically been present. Alewives return (or run) to their natal streams and ponds to spawn each year, which provides the opportunity to monitor each run’s health over time, count the annual returning numbers of fish. This data gathering includes important information about their growth rates and diet as well, which are indicators of the health and success of the species and yield important clues of stressors they may be encountering along the migration route. This annual effort to gather data on how many fish have returned to each river and pond each spring, along with taking fish samples for further study is crucial, and happens fast and all at once! This requires an all-hands on approach at the river-by-river community level.
MCCF helps the Alewife Committee in the Town of Penobscot run a beach seine survey in Northern Bay to identify and understand estuarine habitats that are important for rearing alewife.
Fishermen and community members from the towns of Brooksville and Sedgwick with help from Maine DMR stock pond Frost Pond with alewife prior to fishway restoration projects.
Maine is one of the only states with active commercial harvest of river herring, with 37 municipalities that hold exclusive right to commercial harvest river herring, which provides incentive for fishermen and communities to become involved in the stewardship of this species.
Our Aim & Approach
Maine’s towns have cultural and economic connections to these ponds and fish runs, and volunteers provide local knowledge and stewardship that is invaluable to this collaborative effort. And so while River herring are managed at the federal and state level, Maine towns and municipalities are able to opt to form alewife committees to enable local community scale management. With MCCF help, the neighboring towns along the Bagaduce River created the three-town Alewife Committee of Brooksville, Sedgwick and Penobscot. This has led to an annual event with teachers, students, and local fishermen going out to the streams and ponds in the first week of May to seine for fish, and count the numbers of returns.
To replicate this town committee startup process and support the deployment of broader regional efforts, the Gulf of Maine River Herring Network was established in 2021, and includes more than 50 researchers, fishermen, managers and other stakeholders. The network provides tools and practical advice to enable town committees to be successful in this restoration, and how-to implement with community driven science and management programs that can lead to new fishery opportunities. Maine is one of the only states with active commercial harvest of river herring, with 37 municipalities that hold exclusive right to commercial harvest river herring, and 22 municipalities that actively harvest river herring. This networked effort aims to balance the conservation of these important species with the economic and cultural importance of this fishery to many municipalities.
The network also has a regional website dashboard, which assembles the data from all of the participating municipalities to create a Statewide data set and long term time series that is accessible to Federal and State managers, including the Mid Atlantic Fishery Management Council and Maine DMR. Towns are going beyond just wanting to know how many fish they have and are asking big questions about the role that alewives play in our fresh and marine ecological systems. Alewives are a keystone of the larger ecosystem; the connectivity of our ocean fisheries in the Gulf of Maine, the surrounding watershed communities, and the numerous habitats in between.
Visit the Gulf of Maine River Herring Network:
Partners
Our work at MCCF would not be possible without the help of town governments, community members and other organizations:
Funders
The Broad Reach Fund
Maine Community Foundation
Sarah K. de Coizart Perpetual Trust
Atlantic States Marine Fisheries Commission
Maine Sea Grant
Maine Outdoor Heritage Fund
The Island Foundation
Mid-Atlantic Fisheries Management Council
Cited Literature & Further Resources
Find a River Herring Run
Maine Rivers 2022 Alewife Trail Map
Help Count River Herring (Online)!
Several river herring runs have set up websites where anyone can view video of fish migrating upstream, and help count them from home.
Count river herring in the Pennamaquan River, Pembroke, ME
Count river herring in Town Brook in Plymouth, MA
Count river herring in the Mystic River in MA
Information about River Herring
Maine Department of Marine Resources Maine River Herring Fact Sheet
Maine Department of Marine Resources: All About Maine Alewives
Atlantic States Marine Fisheries Commission: Shad & River Herring
Maine Sea Grant: Connecting Rivers for Healthy Ocean Fisheries
U.S. Fish and Wildlife Service: River Herring
Tools and Data
The Nature Conservancy’s Aquatic Barrier Prioritization tool
Maine Department of Marine Resources Data Portal: Alewife spawning habitat, ME-NH Inshore Trawl Survey Data
SHEDS Stream Temperature Database (ecosheds.org). View and download temperature time-series data using an interactive map.
USGS Interactive Catchment Explorer: Stream Temperature and Brook Trout Occupancy in the Northeast
NOAA Fisheries River Herring/Shad: Herring Catch Cap Monitoring
Management
Atlantic States Marine Fisheries Commission: Shad & River Herring
Maine River Herring Regulations
Best Management/Maintenance Practices Worksheet for Herring Run Management in Massachusetts & Resources and Guidance for writing a River Herring Management Plan. These documents were developed by the MA River Herring Network, and are intended to help MA herring wardens determine what information is known and unknown about their particular run(s), and develop a plan for managing their run(s).
More
Downeast Fisheries Partnership
Downeast Salmon Federation Alewife Monitoring