Mystic River `22 herring run 425,000 plus | Woburn

MEDFORD/WOBURN – More than 425,000 river herring passed the fish ladder at Mystic Lakes Dam in Medford in 2022, and an additional 20,000 fish passed into Horn Pond in Woburn, according to official estimates from the Division of Marine Fisheries (Mass. DMF). . This is the highest documented herring catch of any river in Massachusetts this year.

A recent release notes that efforts are currently underway and funding is being secured to address this issue of the fish ladder leading into Horn Lake.

According to Daria Clark of the Mystic River Watershed Association, “We are encouraged to see a similar herring estimate in 2021 and 2022 despite declines in many other herring stocks. The next big step to increasing the Mystic River herring population is improved stocking in Horn Lake. fish passage.”

Clark and the Mystic River Watershed Association released some of the following about the increase in river herring passing through the Medford and Woburn locations and efforts that will soon include Scalley Dam in Woburn.

River herring – Alewife and Blueback herring – are migratory species that spend most of their lives in the open ocean, but return to freshwater each year to spawn in the river system where they were born. They are threatened by overharvesting in the ocean and, most importantly, by the loss of inland breeding habitat caused by dams closing access to inland lakes and rivers.

According to MRWA, the latest count represents the latest chapter in an ecological restoration success story that has included the installation of multiple fish passes in the river, resulting in a dramatic increase in river herring populations in the Mystic River.

Herringbone figures in context

According to the Mystic River Watershed Association…

“This year’s total is slightly lower than last year’s estimate, but consistent with the feeling that Mystic’s population remains robust. (Fish populations change over time for various reasons). Mystic is often among the largest documented herring runs in the state, but this year was the largest. This is both remarkable and indicative of less positive changes elsewhere.

“This is notable because one would not expect the largest herring population in the state to have to navigate urban waterways — not to mention the Mystic Lakes Dam — Boston Harbor and Amelia Earhart Dam — to reach their spawning grounds. Typically the largest streams in Massachusetts are the Herring River in Wellfleet on Cape Cod Bay. found in rivers with relatively unobstructed flows and protected estuaries.

“However, this year’s herring numbers in other normally high-count areas of Massachusetts were significantly lower than last year. Herring River counts, for example, were 290,000, after counts of more than 1,000,000 in 2019.

As Ben Gahagan of the Department of Marine Fisheries said, “It’s been a really bad year in southern New England.” Similar patterns were seen in Rhode Island and Connecticut: “On the other hand,” Gahagan adds, “Maine had a record run and New Hampshire was actually pretty decent.”

That is, there may be some phenomenon at work that has disproportionately affected southerners in recent years. Multiple causes may be at work, and government scientists say it’s too early to pinpoint a single cause.

One of the main factors in the decline of Massachusetts herring populations in recent years may be the drought experienced in the area. In many river systems, late-summer drought can prevent juveniles from migrating back to the ocean by drying up rivers, reducing population productivity as visible in numbers of adults returning years later.

The mystical system may be relatively immune to this effect, at least for now. Even in relatively severe droughts, there are fewer dead spots for fish to end up in.

More on the environmental success story

A fish ladder was built at Mystic Lakes Dam in Medford in 2012 – allowing fish from the Mystic River to reach Upper Mystic Lake for the first time in decades.

At that time, the Mystic River Watershed Association, in partnership with the Mass DMF, began a volunteer herring count. Each year, dozens of volunteers visit the dam every daylight hour from April to June to take a 10-minute sample count of fish passing into Upper Mystic Lake, and the data is used to calculate the total number of fish passing the fish ladder.

In the first year, approximately 200,000+ fish passed the dam, based on data generated by volunteer counters. However, when river herring become sexually mature, they return to fresh water to breed only at 3-4 years of age. When the first cohort of fish born in the newly expanded freshwater habitat reached reproductive age and returned to Mystic Lakes for the first time in 2015, volunteer estimates showed that the number of fish committed to the Mystic River doubled (Figure 1). Numbers continued to rise over the next few years, reaching 780,000 fish in 2019.

It’s a great success story: A single simple fish ladder at Mystic Lakes has doubled, even tripled, a significant wildlife population. For a sense of scale: At 500,000 feet long, these fish would stretch 100 miles on end!

Next stop: Horn Lake

Volunteer fish counters also tracked fish entering the next large lake upstream of the Mystic River watershed: Horn Lake in Woburn.

Currently, the Scalley Dam at Horn Pond largely prevents fish from entering the lake, although a small proportion of incoming fish form a small cascade that goes around the dam when the water level is high enough.

Based on the number of volunteers, the estimated number of fish that could enter Horn Lake this year was about 20,000.

More fish were seen at the bottom of the dam, most of which had probably turned back upstream.

The good news is that money from two federal environmental damage settlements, including the infamous Superfund case in Woburn, will lead to millions of dollars in investments to build a fish ladder at Horn Lake.

The City of Woburn is also investing in this project, which is expected to be completed in the next few years. Fisheries scientists believe this will further expand the river herring population in the Mystic system.

Horn Lake is also likely to be a place where the general public can view this migration firsthand.

DMF’s Ben Gahagan says, “Woburn has proposed extensive improvements to the park to incorporate the stairs and public viewing opportunities. “I think all parties see public engagement as integral to long-term success.”

Get involved

Will the mystical herring run reach a million fish? Will mysticete continue to lead the state in herring populations? Stay tuned for more from the remarkable urban wildlife migration.

In the meantime, keep an eye out for volunteer opportunities to participate in our in-person and video computing programs. Registration to become a herring monitor for the 2023 season will open in February/March.

And finally, it can never be said enough: All of the data collected on the river herring population in the Mystic River is thanks to volunteer community scientists.

This is public information created by the residents of the watershed. Thank you all.

About the Mystic River Watershed Association:

The Mystic River Watershed Association works to improve the lives of more than 600,000 residents of the Mystic River communities through efforts to protect and restore water quality, natural habitat and open space throughout the 76-square-mile watershed.

The Mystic River watershed consists of 21 communities: Arlington, Belmont, Boston (Charlestown & East Boston), Burlington, Cambridge, Chelsea, Everett, Lexington, Malden, Medford, Melrose, Reading, Revere, Somerville, Stoneham, Wakefield, Watertown, Wilmington, Winchester, Winthrop and Woburn.

For more information, visit


Leave a Comment