Walking to work through Winchester town center a few years ago, John Kilborn peered into the Mill Pond from the bridge on Main Street. He was stumped by a curious sight -- a fish was attempting to climb up the steps of the Center Falls Dam, but was unable to make the leap.
Kilborn, who is a fisherman, didn’t recognize the fish right away, but after some research learned that what he saw was a river herring, attempting to bypass the dam on its way upstream toward spawning grounds in Horn Pond.
Historic migration enabled
So Kilborn began advocating for a fish ladder, a contraption that slows down the velocity of the water, creating an artificial stream that allows fish to migrate upstream around the dam. A fish ladder would enable the long journey of the local herring: from the Atlantic Ocean to the Mystic Lakes, then to Winchester’s ponds and rivers, to Horn Pond and back to the ocean.
After testing the waters and flood control work at the Center Falls Dam, the fish ladder was dedicated in June 2017 and began functioning fully in 2018.
Last year, thanks to the fish ladder, the Mystic and Aberjona rivers hosted one of the largest river herring migrations in the Commonwealth, according to Kilborn.
“This is really amazing, it’s a historic event,” he said.“Because of the cleaner water and new fish ladders, the herring are appearing where they haven’t appeared in at least a hundred years.”
During the migration period between April and June of 2018, a “fish cam” recorded nearly 100,000 herring traversing through the Center Falls Dam fish ladder, a “spectacular” migration, according to Erica Wood, communications manager at the Mystic River Watershed Association. What’s striking, Wood says, is that one of the largest river herring migrations in the region is happening in an urban river in such a densely populated town as Winchester.
“This migration is happening right in our backyard and not a lot of people know about it,” Wood said.
Herring transforming the river
But why all this effort to help the slender, silver-skinned fish travel farther upstream? Herring is considered an “indicator” species, or foundational fish, in the ecosystem, said Erica Wood, the outreach manager for the Mystic River Watershed Association. Fish ladders help herring reach habitat with nutrients where more fish can grow and multiply.
“When herring are doing really well, we can conclude that other wildlife species will be doing well also, and that the water quality is decent enough for them to be in this area,” she said.
The return of river herring, which is considered a threatened species, has also contributed to the comeback of bald eagles, and more night herons and osprey that frequent the Mystic Lakes to feed on the herring.
“The herring are revitalizing the Aberjona River,” Kilborn said. “It’s turning people’s perception of the Aberjona from a storm sewer to a living river.”
Back in the 1870s, the herring used to swarm in Winchester, according to historic records Kilborn said, but human intervention and pollution killed off the fish by very late 1800s.
When herring started returning to the area, some took the effort on themselves to facilitate herring migration across the Mystic Dam. A group of volunteers -- a “bucket brigade” -- fetched the fish at the Mystic Dam in large 10-gallon buckets and transferred them over the dam. In the late 2000s, they counted about 20,000 during the migration period. Since a fish ladder was installed at the Mystic Dam in 2012, the number went up to 200,000, and last year up to 600,000.
Counting the fish
Armed with clickers, volunteer monitors count the herring, accounting for each fish that crosses the ladder.
“We ask them to do their best guess,” said Wood.
Herring monitors stand in a designated spot at the Mystic Dam from April to June from 7 a.m. to 7 p.m to count how many herring traverse over the ladder. Counters see anywhere from 10 to 1000 herring in a 10-minute interval, Wood said. Volunteers can also do the counting online through underwater webcams. Wood hopes more volunteer counters join the upcoming season, both in Horn Pond and at the Mystic Dam.
It’s more than just tallying up fish, she said.
“The more we know about river herring and the larger the populations, the more we can advocate for a clean Mystic River,” she said. Supporting the herring means restoring the habitat, and, in turn, restoring the river, she noted.
The herring are bringing the whole area back to life with the rush of sounds of the spawning herring and the birds flying around.
“It’s a thrilling movement and migration that really connects us up to the ocean and is restoring the Aberjona back to life,” Kilborn said.