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The Importance of Doing Fish Counts

The presence of fish especially the Alewife is an excellent indicator to reveal the health of the river system.     Fish counts are maintained and relayed over a period ot time to help monitor the water quality and environmental pressures on the river.

Alewife Volunteer Counts

 The Parker River Clean Water Association conducts a count of the Alewife fish every spring from early April 1 to mid May in order to determine how many fish are now able to make their way upstream. 

Each time slot is an hour, and your commitment is to stare at the water and count fish for 2 5-minute timeslots, any time in that hour!  You will also measure water and air temperature, and make weather observations.

We have a regular schedule, with volunteers making weekly commitments (example: Tuesdays & Thursdays, 2-3 pm) or you can fill in as you’re available

We hope that you will join us in this effort!


                             Have you seen this fish?                              










The Alewife (Alosa pseudoharengus) is a type of river herring which returns every spring from the ocean to spawning grounds in upstream ponds. Although there are fish ladders built around dams, many of these are not in good repair, or are of poor design.  Between these obstacles to swimming, and pollution levels, the Alewife population is in danger.

Recent counts show a decline of over 70%  in comparison with counts from the 1970s.  PRCWA relies on volunteers from the community to help us in the fish count.  

Anadromous Fish of the Parker River


Anadromous fish are fish that are born in freshwater rivers, streams, and ponds but spend most of their lives in salt water. The adults return to freshwater, usually to the stream in which their were born to spawn. Human activities, most notably dams, have severly impacted the ability of many anadromous fish to return to their home stream. Well designed fishways (fish ladders), however, can alleviate the problem and provide these species with the means to make the passage upstream.

From the very beginning of colonial settlement in the Parker River basin, laws were passed to regulate fishing and by the late 1700's there was considerable concern about the decline of fish populations in the Parker River.

Anadromous Fish Still Present in the Basin


Blueback Herring

Sea Lamprey


Striped Bass

White Perch


There are many environmental factors that affect fish populations.  These are documented in a report done by the U.S. Geological Survey and the Massachusetts Department of Fish and Game:


Factors Influencing Riverine Fish Assemblages in Massachusetts.


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