Brunswick Hydroelectric Dam. Fish must enter the fish ladder (left) at the base of the brick structure and zigzag upward to reach the top of the dam.
Last week Bowdoin’s John Lichter, director of the college’s environmental studies program, was featured on local news for his project aimed at helping fish bypass obstacles on their way up Maine rivers. An array of migratory fish species have declined in numbers since the first days of industrialization, blocked from their spawning grounds by a gauntlet of dams.
While it was clear early on that dams caused migratory fish harvests to drop, only recently have researchers been probing the wider ecological and economic impacts. “These fish are feeding the cod and haddock and groundfish species out in the ocean as well,” Lichter said, and their decline has been contributing to the struggles of offshore fisheries.
The Brunswick Hydroelectric Dam, Lichter’s study site on the Androscoggin River, is home to a fish ladder — a sloping series of pools that zigzags from the base of the dam to the top — and a device that creates currents to attract fish to the entrance of the ladder. These measures have helped certain species, like salmon, scale the dam, but have proven particularly ineffective for American Shad. Underwater cameras reveal thousands of shad just downstream of the dam, but far fewer reach the ladder’s entrance—and so far this year only a couple dozen battered individuals have made it all the way up to the top.
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- The fish must swim uphill through a series of pools to reach the top of the ladder.
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- Near the top of the ladder is a public viewing room where visitors can watch fish swim by.
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- Footage from underwater cameras has shown that American Shad are abundant downstream of the fish ladder, yet only a couple of dozen have made it all the way to the top in the past year.
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- Nate Niles ’15 is assisting Lichter with a summer research project to determine whether installing a fish lift (essentially an elevator for the shad) is feasible for this site.
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- Wading boots line the entryway to the fish ladder’s control room. Here Niles can view footage from underwater cameras to determine the number of shad in the fishway.
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- Lichter examines the dials in the fish ladder’s control room.
Lichter’s summer research student Nate Niles ’15 is counting and identifying the shad captured on underwater cameras placed at different spots downstream of the dam, to get the ball rolling on figuring out the best way to help them reach their spawning grounds. Niles and Lichter are exploring the feasibility of installing a fish lift—an elevator that transports fish up and over the dam. It comes with a high price tag but could potentially be the key to opening up the shad’s route to recovery.
Throughout this research process Lichter is keeping practical and large-scale goals in mind. “We’ve been trying to engage business and industry,” Lichter said. “We want to get something done rather than just publish papers somewhere.” The goal is to improve matters not just for the fish on the Androscoggin but for whole river and coastal ecosystems — and the human population as well. As Lichter points out in the news clip, “economic recovery may depend on ecological recovery.”
Photographs and captions by Catherine Yochum ’15
