The rain and wet conditions during the spring and early summer may not have been good for outdoor recreation, but it likely helped with the return of Atlantic salmon, which are federally protected under the Endangered Species Act, to the waters of the Penobscot River.
An estimated 1,489 salmon have passed through either the fish lift in Milford or the Orono dam so far in 2023 as of July 22, said Jason Valliere, marine resource scientist for the Maine Department of Marine Resources. That continues a positive trend for Atlantic salmon returns. It marks the most fish counted since 2012.
As was the case last year, it is likely that higher river flows resulting from extensive spring and early summer rains played a role in cooling the water and enabling Atlantic salmon to ascend the rivers and get into fishways more efficiently in 2023.
After a recent low of 772 salmon were seen in 2018, the numbers have generally been better. Returns in the Penobscot were 1,196 in 2019, 1,440 in 2020, a disappointing 561 in 2021 and 1,324 salmon in 2022.
That’s an average of 1,202 over the last five years.
“We are up to 1,455 salmon. It’s been a good year thus far,” Valliere said in his July 12 report. “Let’s hope they keep coming and we see another good push this fall.”
Maine is home to the only remaining populations of wild Atlantic salmon in the United States. The Penobscot River features the state’s most productive salmon run, but fishing for them is prohibited.
Another species that has continued to flourish in the Penobscot since the removal of the Bangor dam is river herring, which includes alewives and blueback herring.
This year’s count is well above the previous high, with an estimated 5,490,195 having passed the Orono and Milford dams. That shattered the existing year-to-date figure (through July 22) of 2.9 million fish that was recorded a year ago.
Since the removal of Bangor’s Great Works Dam in 2012 and the Veazie Dam in 2013, river herring have surged from 200,000 in 2014 to nearly 5.5 million in 2023.
Farther to the south, the Kennebec River also has experienced an unusually productive Atlantic salmon season.
The Kennebec remains a much less attractive option for Atlantic salmon, which cannot get past the Lockwood Dam in Waterville — the first of four hydroelectric projects on the river operated by Brookfield Renewable — without being captured in a tank and then transported by truck approximately 50 miles to traditional spawning grounds in the Sandy River.
Despite those dynamics, DMR personnel have been busier than usual counting and handling Atlantic salmon in the Kennebec. Through July 24, a total of 151 salmon had made their way through the Lockwood and Benton Falls dams.
That is the most since at least 2011 and comes on the heels of a 2022 season during which 87 Atlantic salmon were reported. The average over the 10-year period from 2012-2021 was only 28.3.
Sean Ledwin, the sea run fisheries and habitat director for the Department of Marine Resources, said previously that numerous factors affect how many Atlantic salmon come into Maine rivers in a given year.
The key dynamics included the survival level of the fish while at sea, the water conditions that exist during their time in the river and the hurdles Atlantic face trying to get around or through dams at hydropower projects.