Back in April, my husband, Rob, and I volunteered to count migrating alewives, a type of river herring, at the fish ladder on the Concord River in Lowell. Each spring, the silver fish, which are about 5 or 6 inches long, make their way back from the ocean, where they have spent most of their lives, to the places where they were born in order to spawn.
The counting effort is part of an overall strategy to determine what steps are needed to restore habitats for these migrators, including changes to the Talbot Mills Dam in Billerica, farther upstream. The Lowell Parks & Conservation Trust organizes the program with help from the U.S. Fish & Wildlife Service. Financial support for the project this year came from a grant provided by 3Mgives (3M has an office in Chelmsford). The project also supports research by the UMass Lowell biology department to better understand biodiversity in the Concord River.
A healthy alewife population is essential to the well-being of the ocean overall because they are near the bottom of the food chain. Known as “forage fish,” alewives are an important source of nutrition for several larger species. Migrating herring also provide sustenance for birds and other wildlife that live in and around the rivers where they spawn.
The herring-monitoring program in Lowell is one of several in the region. Similar efforts occur on the Mystic River in Medford and the Ipswich River in Ipswich, among other places.
Lowell’s fish ladder is on Centennial Island. Located off Lawrence Street, behind Lowell Cemetery, the manmade landmass is home to a hydroelectric generator and an old mill building that’s being turned into a high-end apartment complex. The fish ladder, which looks something like a concrete chute, is necessary for migrators to cross the Centennial Dam, known to locals as Wamesit Falls. Without the ladder, the fish’s long journey from the Atlantic, up the Merrimack and Concord rivers, would end right there.
Before you can count fish, you have to attend a short training session. Rob and I, along with a dozen or so other volunteers, did this one chilly Saturday morning in April. We learned all about alewives and other migrating fish native to the area. A representative from U.S. Fish & Wildlife explained how and why river herring migrate, and how studying them in places like the Concord River is important to understanding the general health of the oceans.
We were introduced to the fish ladder, learned the proper way to count moving fish (with a clicker), and got to check out the historic gatehouse where the flow of water in the canal between the riverbank and the island is regulated.
Although I wasn’t expecting it, I found myself feeling excited after the training ended. I couldn’t wait to go back to Centennial Island and begin counting fish. More than anything, I wanted to cheer on the little guys as they swam up the fish ladder and headed upstream to the places where they would give life to the next generation of alewives, fish that would help nourish countless dolphins, seals, whales and seabirds.
Fish-counting shifts last just 10 minutes, during which you stand over the ladder and stare at a white stripe that has been placed below the rushing water to provide contrast to the moving fish, making them easier to see. You’re supposed to take note of the weather and other types of wildlife in the area. Sometimes it’s kind of boring, especially when you don’t see any fish.
But the experience helped me learn that important science isn’t always conducted by people in white coats working in some sterile laboratory far away. Sometimes it takes something wild, like a small fish that has swum hundreds of miles and defied great odds, to make the difference between us gaining a better understanding of our world and making positive changes, and maintaining outdated ideas and practices.
Scientists rely on data. But those alewives and the ancient rhythms of life they represent are the closest thing to magic I’ve seen with my own eyes. They prove that if we remove the obstacles we have set in its path, the natural world can resume functioning much the way it always has, even in post-industrial cities like Lowell.