Alewives counted one-by-one on Mill Brook

posted May 19, 2015, 4:22 AM by Joseph Bickard   [ updated May 19, 2015, 4:25 AM ]

Every few seconds, a dark gray alewife darts up the ladder and over the dam on its way to spawn in Highland Lake. Volunteers' carefully count every fish that makes its way over the ladder in a timed 30-minute period, clicking a hand-held digital counter for each alewife that passes.

But the peaceful – some might say tedious – process of counting fish belies a statewide sense of urgency and concern among scientists, fishermen and conservationists about the future of one of Maine’s most important fish. That concern has prompted hundreds of volunteers to participate in spring alewife counts and other projects dedicated to boosting the species’ numbers in Maine.

The alewife, which returns from the Atlantic each spring to spawn in lakes and ponds, has had a drastic drop in population from its southernmost habitat in North Carolina all the way into Newfoundland.

“The runs are a shadow of what they used to be,” said Claire Enterline, a marine scientist and alewife expert for the Maine Department of Marine Resources.

In the mid-1970s, about 35,000 metric tons of alewives, also known as river herring, were landed by commercial fishing in the United States. Thirty years later, fewer than 50 metric tons were landed, according to the National Marine Fisheries Service, which has put alewives on its list of species of concern.

It is time to gear up and prepare for the River Herring run count at Millbrook Dam at HighlandLake in Windham, Maine. 

This also means it is time for the Annual In-person Training for those who want to visit or revisit the site, review the process, and/or ask any questions you have - like why are we counting river herring, or what is the data used for?

On May 9th, from 8am- 12pm:  volunteer training - its a very easy process, I promise. The handheld click counter, data sheet, and pencil are provided and stored on site for convenience. 

Missed the training? email jason at

All ages are welcome - seeing the herring run the brook and fish ladder is a really fun activity for the kids and adults alike! 

Last year, the herring started running on May 20th and ran to about June 15th, with about 49,000 fish passing the dam."

Check out the video showing our own Presumscot River alewife migration.