The Alewife

The name alewife, or river herring, describes two types of anadromous fish:

  • Blueback Herring – Alosa aestivalis
  • Alewife – Alosa pseudoharengus

Anadromous Fish are born in fresh water, travel to salt water to live and eat, and return to fresh water to spawn.

Alewives are considered essential for the restoration of Gulf of Maine commercial fisheries.

Alewives spend the majority of their life at sea but return to freshwater to spawn. Just a few months after they hatch, young alewives leave the fresh water and head out to sea.  They start making the journey back to freshwater annually when they are 3 to 5 years old and may make the trip 3 to 4 times in their life.  The alewife migration takes place in April and May, and as soon as the fish are done spawning, they return back to the ocean (June).  The alewife species spawns in lakes, and the blueback herring species spawns in streams or rivers.  The front of their bodies and abdomen are relatively large compared to the rest of their bodies, and the common name is said to come from a comparison made by early English settlers of this shape with that of a large female tavernkeeper (“ale-wife”).   fish 1

Alewives are Important!

  • They are one of the key fish that form the bottom for the food chain in the Gulf of Maine.
  • They are food for striped bass, bluefish, tuna, cod, haddock, halibut, American eel, trout, smallmouth bass, largemouth bass, pickerel, pike, white and yellow perch, seabirds, bald eagle, osprey, great blue heron, gulls, terns, cormorants, seals, whales, otter, mink, fox, raccoon, skunk, weasel, fisher, and turtles. Wow!
  • Alewives tie our ocean, rivers and lakes together, providing vital nutrients and forage needed to make healthy watersheds.
  • Alewives provide cover for migrating adult and juvenile Atlantic salmon.
  • Adult alewives are preferred bait for the spring lobster fishery.

Wildlife Enjoying the Alewives at Nequasset Dam (Photos by Howard Cederlund)

eagle hc crop gull hc crop heron 2 hc crop loon hc crop osprey 2 hc crop

 Alewives are in Trouble – Alewives were recently listed as a “species of concern.”  Unfortunately, many Mainers have never seen an alewife run because Maine’s historically thriving alewife population has plummeted during the last two centuries.  Their population has dropped primarily because access to their spawning grounds is blocked by dams, culverts and road fill. Less than 5% of former spawning ground for anadromous fish remains accessible in the State of Maine due to barriers such as dams and culverts.

In 2010, KELT completed the Kennebec River Barrier Survey, inspecting more than 400 road-stream crossings in the Kennebec Estuary watershed. 172 of these sites were found to be barriers to fish passage. These sites were prioritized for restoration based on stream miles upstream of the barrier as well as barriers downstream. The Nequasset fish ladder ranked #1 according to these parameters.  The active stakeholder base and the amount of suitable habitat above the dam also helpted to bring the Nequasset Fish Ladder to the top of the list.  Fisheries experts estimate that with proper management and improved passage this site can support 400,000 fish.

Nequasset is one of only 39 sites in Maine where alewives are harvested.  Maine is one of only 2 states that allow commercial harvest of alewives.

Managing Alewives at Nequasset

To properly manage the important alewife run at Nequasset for long term sustainability, data is needed on how many fish attempt to access the spawning grounds of Nequasset Lake.  Volunteers at KELT’s Nequasset Ladder Fish Count have been helping to collect this valuable information since 2012.

Check Out Other Great Resources About the Alewife:

Alewives in Maine – Fish and Wildlife Service
Maine Department of Marine Resources – Alewife facts
Gulf of Maine Aquarium
Kennebec Estuary Land Trust restoration project site
Desperate Alewives MPBN video
KELT video about Nequasset 

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