River-watchers had a reason to celebrate last week as the unofficial total of returning Atlantic salmon reached 1,000 for the first time in eight years.
As of July 14, that total stood at 1,059, according to Jason Valliere, Marine Resources scientist for the Maine Department of Marine Resources’ Division of Sea Run Fisheries and Habitat.
Only 671 salmon were counted at the Milford Dam fish lift a year ago. The last time more than 1,000 fish were documented as returning to the Penobscot River was in 2011, when 2,915 fish were counted at the Veazie Dam, which has since been removed from the river.
Atlantic salmon are listed as “endangered” under the federal Endangered Species Act in all Maine rivers, and fishing for them is not allowed.
The total is tentative, and subject to change, Valliere said. A reason for the uncertainty is that crews follow a different set of rules when the river water is at the temperature it is now — about 80 degrees — in order to avoid stressing the fish.
Instead of handling fish, measuring them, taking a scale sample and inserting a tag that allows researchers to track the fish as it moves through the hydro dams, the fish swim freely upstream.
“The fishway continues to operate but the gates are left open so fish can swim freely into the headpond. In this situation we depend on video count for enumeration,” Valliere said.
That can lead to a bit of confusion, as fish may end up swimming past the camera more than once and be counted more than once.
“Since fish are now passing the fishway unhandled and unmarked there will be some fluctuation in our estimate as data becomes available. Currently every fish is being counted as ‘new,’” Valliere said. “We will later review PIT [Passive Integrated Transponder] tag data to identify any fish that was previously handled which will reduce the count some in the future as we determine some of the fish we originally called ‘NEW’ were not.”
And passing the 1,000-salmon barrier was not the only milestone at the Milford fish lift: Valliere also announced that the crew had captured its first endangered shortnose sturgeon of the season. The fish — the sixth sturgeon caught at the facility since it became operational in 2014 — was tagged by University of Maine researchers and released downstream of the dam.
The good news about salmon returns to the Milford Dam fish list is tempered by the fact that in February the National Oceanic and Atmospheric Administration and the U.S. Fish & Wildlife Service released their plan for the recovery of Atlantic salmon within the Gulf of Maine distinct population segment. It estimated that it will take 75 years, about 15 generation of fish, for Gulf of Maine Atlantic salmon to be delisted.
In 2009, the Penobscot River was included in the expansion of Endangered Species Act protection for Atlantic salmon originating in Maine.
The Gulf of Maine distinct population segment of Atlantic salmon was originally listed as endangered in 2000. That listing covered fish returning to smaller rivers in the state.
Watch: Salmon restoration efforts in Piscataquis River