AUGUSTA, Maine — A plan to reopen river habitat to Atlantic salmon and other sea-run fish could enable an invasive species to infiltrate a prized fishery, biologists and anglers told Maine legislators Tuesday.
Northern pike, a non-native species that preys on such fish as salmon and trout, could decimate the Piscataquis River watershed, said retired fisheries biologist Paul Johnson.
Johnson told the Fisheries and Wildlife Committee that inland pike, which have been introduced illegally into Pushaw Lake north of Bangor, could swim downstream to the Penobscot River. From there, they could make their way upstream and north to Howland, where the Piscataquis is blocked from the Penobscot by a dam.
A nonprofit group called the Penobscot River Restoration Trust, which includes the Penobscot Indian Nation and several conservation groups, proposes a bypass channel around the dam as part of a plan to restore fish such as Atlantic salmon, river herring and sturgeon to the upper reaches of the Penobscot River and its tributar-ies.
The plan also calls for removal or improvement of fish passages in some downstream dams.
By getting past the Howland dam, northern pike would have access to about 40 percent of the Piscataquis River drainage, Johnson said. That could include at least 25 miles of the Piscataquis River’s main stem; 27-plus miles of the Pleasant River, including its east and west branches; the Seboeis Stream drainage; and many small tributaries, he said.
Those rivers and tributaries provide wild brook trout and Atlantic salmon habitat essential to the Penobscot Restoration Project, Johnson has said. He has described the northern pike as “very efficient predators” whose main diet from the time they are 2 inches long is mostly fish.
The Piscataquis County commissioners also have expressed concern.
“It would be great to restore the salmon, but we don’t want to ruin what we’ve already got in the process — people come here to catch trout,” Commissioner Eric Ward told the Bangor Daily News last week.
Johnson told lawmakers Tuesday that the threat is largely unknown to the public and asked for their intervention.
But Laura Rose Day, executive director of the Penobscot River Restoration Trust, said the problem is well-known and has been considered as the group developed its plans to restore sea-run fish.
Ray B. Owen Jr. of Orono, a former commissioner of the state Department of Inland Fisheries and Wildlife and a proponent of the plan, said in an essay published in the Bangor Daily News in February that “one of the best ways to reduce any negative impacts of these invasive fish is to restore the abundance of native fish in the river through the full implementation of the Penobscot project.”
Owen said he does not believe the project “should be jeopardized by the threat of invasive species. Where appropriate, safeguards can be put in place as the risk is further assessed.”
Others associated with the trust noted that the public comment period for the restoration project remains open and the Federal Energy Regulatory Commission could take the issue into account in its environmental assessment.