Fish passage in the Connecticut River has had a rough year as changing environmental conditions continue to impact their numbers and migration, according to biologists for the U.S. Fish and Wildlife Service.

“It’s disappointing,” said Kenneth Sprankle, project leader at the Connecticut River Fish and Wildlife Conservation Office of the U.S. Fish and Wildlife Service. “We’d like to have more fish, certainly. It’s not unique to the Connecticut River.”

Fish passage is the ability of fish or other aquatic species to move between and within waterways during various life stages to reproduce, feed and contribute to their ecosystems, according to the U.S. Fish and Wildlife Service.

As of the June 27 report, which Sprankle recently presented to members of the Connecticut River Atlantic Salmon Commission (CRASC), roughly 190,000 American shad passed through the Holyoke fish lift, and 23,000 passed through the Gatehouse Ladder in Turners Falls (as of June 1). For reference, Sprankle said the federal agency has a goal of 700,000 in Holyoke and 400,000 at Turners Falls.

Fish species under restoration in the Connecticut River basin include American shad, blueback herring, sea lamprey, American eel and alewife.

Sprankle said the population goal, for American shad, for example, would be 1.7 million adults back at the river mouth.

“That allows us to have targets at each of the dams,” he said.

Fish passage season can be greatly affected by water temperature and river discharge conditions, Sprankle explained. Climate change has also impacted several fish populations, namely the Atlantic salmon.

“We’re doing all these things, and what’s frustrating and difficult is nothing stays the same,” he said. “For example, with climate change, as we gather data — the very data we’re gathering becomes outdated in a relatively short period of time.”

In addition to changes to the landscape as a result of clearing land and erosion, structures such as dams and culverts, which have cropped up along waterways over the last several decades, have also impacted fish access to habitats for spawning and nursery. As a result, goals for fish passage numbers have been adjusted to reflect what conservationists consider to be “more realistic” than what was agreed upon in the 1960s when state agencies began working together to restore migratory fish in the Connecticut River.

Responding to criticisms from the community that the turbine at the FirstLight Hydro Generating Co.’s Northfield Mountain Pumped Storage Station — which is in the midst of the license renewal process with Federal Energy Regulatory Commission (FERC) — has played a significant role in the diminishing fish population, Sprankle said the fish-passage systems in place were built in the 1980s and based on designs from the West Coast that were scaled down.

“When that happened, it really changed some of the dynamics of how the water flows through those fishways,” he said. “We’re going to be able to get that changed.”

He added that the challenge on the Connecticut River is that re-licensing schedules aren’t on the same timelines.

The U.S. Fish and Wildlife Service, he said, has fish passageway engineering criteria that will need to be met.

“We have recommendations on things like water velocities, the size of the buckets that move the fish, how much water needs to be available so fish can find fishways entrances,” he said. “This has all been developed through trial and error. … The power companies, the engineers they hire, will utilize that, and we make it contingent that they are meeting that criteria.”

Sprankle said when considering fish counts for a particular year, he also looks to the “stock structure,” or in other words, the age of the fish, as an important marker for success. Often, the fish counts one year can be explained by a poor or successful spawning in the years prior.

“That shows stock resilience,” he said. “If you have fish that are coming back, they’ll come back again and spawn again.”

Reporter Mary Byrne can be reached at mbyrne@recorder.com or 413-930-4429. Twitter: @MaryEByrne

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