Herring Count

Each spring, trained volunteers count river herring swimming up the fish ladder on the Ipswich Mills Dam. Since 1999, IRWA has organized this yearly count in order to estimate the number of river herring returning to the Ipswich River to spawn. Trained volunteers sign up for 10 minute time slots throughout the day. Data from prior fish counts is available here.

Learn more about why we count herring in the Ipswich River, the history of the fish count, and the types of fish in your river.

There’s one now! Counting fish is a fun and easy way to make a difference for river herring.

View of the fish ladder and Ipswich Dam.







River herring or alewife and blueback herring were once abundant in the Ipswich River.

River herring begin their lives in freshwater. Juveniles swim downstream in the fall and, using their sense of smell, return to their breeding stream 3 to 4 years later, when they are roughly 10-11 inches long. Adults initiate spawning at 57 degrees F, and cease spawning when water temperatures reach 81 degrees F.

The Ipswich River’s once thriving populations of alewife (a species of river herring) served as a major source of food and income for the early settlers of the watershed. Unfortunately, this fishery has been severely impacted due to obstructions on the main stem of the river (keeping alewife from reaching their spawning ponds) and the use of spawning ponds for municipal water supply.

We are excited about the new underwater video camera that operated at the top of the fish ladder on the Ipswich Dam during this year’s count (April – June). The camera operated 24-7 and recorded movement through a specially designed box. We hope the camera will help us to better understand and protect the wildlife of the river.

Here is a summary of the 2015 video footage from this year’s herring count season. Keep your eye out for lamprey, brook trout, herring and even river otter and a snapping turtle passing through the Ipswich Mills Dam fish ladder!


Information for volunteers:
Fish Count Location:

View IRWA Fish Count Location in a larger map

Information for Volunteers:

River HerringView the HERRING COUNT TRAINING presentation for instructions on how to participate in the fish count.





Watch the following videos for examples of what herring and other fish you may see look like.


The Division of Marine Fisheries installed a trap at the top of the fish ladder to monitor the health of river herring populations and stocking efforts on the Ipswich in previous years. This data will also help IRWA to check our statistical methods for estimating herring populations from our volunteer counts.

Division of Marine Fisheries Fish Trap Results
Species 2006 2007 2008 2009
River Herring 377* 153 Alewife 5 Blueback 130 Alewife 1 Blueback 187 Alewife
1 Blueback
Sea lamprey 347 1199 1021 254
American shad 4 1
Other 24 American Eel, 4 Brown Trout, 15 Yellow Perch, 2 Largemouth Bass, 2 Golden Shiner, 1 Pickerel, 22 Bullhead, 7 Bluegill 2 American Eel, 8 Brown Trout, 29 Yellow Perch, 11 Largemouth Bass, 3 Golden Shiner, 5 Pickerel, 1 Bullhead,  22 Sunfish 2 American Eel,
42 White Sucker, 1 Creek Chubsucker, 20 Yellow Perch, 6 Largemouth Bass, 23 Golden Shiner, 1 Pickerel, 3 Bullhead, 18 Sunfish, 4 Bluegill, 22 Pumpkinseed
3 White Sucker, 22 Yellow Perch, 25 Largemouth Bass, 11 Shiner, 11 Trout, 1 Pickerel, 40 Brown Bullhead, 1 Bluegill, 17 Pumpkinseed

*Counting stopped early in 2006 due to the May floods.

If you would like more information or are interested in participating in the count, please contact the Program Coordinator Ryan O’Donnell at rodonnell@ipswichriver.org.

Click here for more information on fisheries in the Ipswich River, and here for more information on how we are working to improve fisheries’ health.