Department of Marine Resources researchers Danielle Frechette, left, Matthew Brewer with a portable antenna, and Maddy Young receive data from fish transmitters as the fish make their way up the Presumpscot River at Saccarappa Falls in Westbrook. Chance Viles / American Journal
Scientists are using fish tracking devices to study the efficiency of the new fish ladder at Saccarappa Falls in Westbrook, one of the final steps toward the project’s official completion.
The Maine Department of Marine Resources is catching fish at the Cumberland Mills ladder, inserting radio transmitters into their esophagi and releasing them back into the Presumpscot River, according to researcher Danielle Frechette. As the fish with transmitters swim upriver, they are detected by radio antennas, allowing researchers to see how far up the river they end up and whether they used the fish ladder.
“When the fish swims by, the radio will catch it and a code comes up allowing us to organize it,” researcher Matt Brewer said.
The researchers also are conducting active tracking using portable antennas, Frechette said, “where we will go out and survey specific spots of the river for fish.”
The tracking is important, she said, because the ladder may require some tweaking if fish aren’t using the ladder to the degree expected. Changes could include readjusting the water flow or clearing any obstructions that might be revealed in the study, which will continue for another few weeks and then resume for another round of testing next summer.
“We will then take this data and either have a preliminary finding, or release our findings after the second half of the surveys,” Frechette said.
A tracking transmitter that is carried by the fish. Chance Viles / American Journal
After two summers of tracking, Frechette said, she and her team will have a much better idea of how well the fish ladder works.
Most of the work on the ladder was completed in late 2020, and last summer saw the first significant fish passage through Saccarappa Falls since the 1700s, but the ladder study was pushed off until this year because of the pandemic.
The study now occurring is a big step, said Mike Shaughnessy, president of Friends of the Presumpscot River, which was instrumental in Sappi’s removal of the dam and installation of the ladder.
Shaughnessy said the ladder seems to be working.
“It’s a critical point we are at with getting it tested in case it needs something else, but my hope is nothing else needs to happen,” he said. “There are funds reserved for post-construction adjustments based on what happens with the effectiveness testing, but so far it is very encouraging.”
As a result of the study, changes also could be made to a channel created when the dam was removed.
Shaughnessy said thousands of fish likely have made their way through the ladder, but the testing is important in differentiating which species of fish actually are passing through the ladder and which might be opting for the channel for whatever reason.
“I’m excited by this and this will be key to us signing off on these things,” Shaughnessy said.
Talks about removing the Westbrook dams for the benefit of wildlife began over 20 years ago. In 2006, the U.S. Supreme Court upheld the Maine Department of Environmental Protection’s ability to require fish passage and minimum water flow standards around the Presumpscot River dams as part of water quality certifications required for federal relicensing.
The dams, once owned by S.D. Warren, were owned by Sappi, which was responsible for their removal and the fish ladder construction.
An antenna at the entrance to the Sappi fish ladder tracks the fish that go in, and other antennas inside track their progress. Chance Viles / American Journal
In addition to the fish ladder, areas around the former Sappi dam on the Presumpscot River, like the one seen above, were engineered to make it easier for fish to swim upriver. Chance Viles / American Journal
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