An Atlantic salmon makes its way to a holding tank at the Milford Dam fishway at Brookfield Energy in Milford Wednesday. Credit: Ashley L. Conti / BDN

Each spring and summer for more than 40 years, anglers and conservationists have turned their attention to the Penobscot River at this time of year as they wonder how many Atlantic salmon will return as part of the annual run.

Nowadays, staffers from the Maine Department of Marine Resources don’t stop at salmon — they count all variety of fish species when they arrive at the fish-sorting facility at the Milford Dam. And so far this year, the counting has kept the crew super busy: A record number of American shad have made their way into the fish elevator, and the salmon are arriving at the fifth-fastest rate since counting began in Veazie back in 1978.

Thus far this year, 9,190 shad have been counted, breaking the previous season record of 8,231 set in 2016. In a single day this spring — June 5 — 3,844 shad were counted at the facility. That’s more shad than the entire 2019 run.

Add in another 1.9 million river herring and 5,537 sea lamprey, and the river is teeming with fish returning from the ocean.

And when it comes to the river’s marquee fish — the Atlantic salmon — 723 have already been counted. Only four times in the last 42 years have more salmon been counted by June 6. The high-water mark in that regard was set in 2011, when 1,622 salmon had been counted. On the same day a year ago, just 93 salmon had made their way into the dam’s fish elevator.

Sean Ledwin, the director of the DMR’s division of sea run fisheries and habitat, said the results thus far have been encouraging.

“We were very excited to see the largest run of shad and second largest run of river herring at the Milford dam on the Penobscot this year, supporting many interests including significantly improved angling opportunities for migrating shad looking to spawn and striped bass that follow the river herring upstream,” Ledwin said. “The dam removals and passage improvements as part of the Penobscot River Restoration Project and watershed work by the [DMR] and partners are working.”

The PRRP was an ambitious project that took more than 16 years and $60 million to complete. During the project, two dams were removed from the lower Penobscot and fish passage was created by bypassing another dam. As a result, more than 1,000 miles of river, lake and stream habitat were opened to fish returning from the sea.

Shad were among the key beneficiaries of the project, and are now swimming farther up the Penobscot than they were able to for the 150 years dams blocked their progress.

Salmon runs fluctuate from year to year, and Atlantic salmon are listed as endangered by the federal Endangered Species Act. A group of conservationists is also trying to get Atlantic salmon added to the Maine endangered species list. Fishing for them in any Maine river is prohibited.

Continued cool weather and chilly water temperatures in the Penobscot could lead to an extended run for salmon. An extended hot spell and rising river temps could shut the run down.

“Salmon are a coldwater species and are very sensitive to warm water. Optimal temperature is about 60 degrees [Fahrenheit], but temperatures can be fine for salmon from 40 to 70 degrees,” Ledwin said. “Above 75 degrees is when we stop handling salmon as they are likely in a stressed situation. We often reach that temperature in July.”

According to Jason Valliere, a marine resource scientist for the DMR, the water temperature at Milford on Wednesday was 73.5 degrees.

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John Holyoke

John Holyoke has been enjoying himself in Maine's great outdoors since he was a kid. He spent 28 years working for the BDN, including 19 years as the paper's outdoors columnist or outdoors editor. While...