Back to Schools: Restoring fish populations to the Pawtuxet River

Alewife (left) and Blueback Herring, collectively known as River Herring. Illustrations from USFWS.

For 200 years or longer, dams have blocked a number of important species of anadromous fish from completing their lifecycle.

Alewife, blueback herring, and American shad are just a few of the anadromous species that live their adult life in saltwater but return to freshwater to spawn and whose populations had virtually disappeared from the Pawtuxet River watershed following the Industrial Revolution.

“If you put a dam in a flowing body of water, you can use water to power America,” says Robert Nero, chairman of the Pawtuxet River Authority.

“That’s what Samuel Slater did, and the Brown family in the late 1700s. They copied what they saw in England at the time of the original industrialization of this country and began using hydropower to run looms. Dams started popping up all around the state.”

In Pawtucket, where Slater built his company, Rhode Island rivers were teeming with Atlantic salmon. Once the dams were built, that population, and many other indigenous species, disappeared.

“They just died out here,” says Nero. “They couldn’t make it back to their spawning grounds. You can be certain that most of the rivers in New England that empty in the ocean … every one had major fish populations for thousands of years until the Industrial Revolution.”

The smaller freshwater fish were foraging for larger saltwater fish and other animals, so when that important food source disappeared, so did the species feeding on them. The entire ecosystem changed as the dams were constructed. Ruing the absence of fish and wildlife in the area, Nero had a vision. Inspired by the progress made restoring fish populations in the Wood and Pawcatuck rivers, he set his sights on doing the same for the Pawtuxet, where a 250-year-old dam at the foot of Pawtuxet Village obstructed anadromous migration patterns.

“We just wanted to return the river to what it naturally was,” says Nero. “We wanted to restore these fish populations to the Pawtuxet. But in order to do so, we had to remove the dam.”

At DEM, dam removal is the last option. But Nero, working with fish and wildlife experts, demonstrated that removal, in this case, was for the greater good.

In the culmination of a nine-year effort, Nero oversaw the deconstruction of the 150-foot Pawtuxet Falls dam in 2011. The $600,000 project, which involved DEM, the Pawtuxet River Authority, the Narragansett Bay Estuary Program, and other partners, removed the center section of the dam, enabling water to flow freely over the natural bedrock falls for the first time in over two centuries.

Since then, the river has come beautifully back to life, restoring vital connectivity between Narragansett Bay and the streams and ponds of the Pawtuxet. Massive migration is underway once again, with schools of herring and shad now able to reach their spawning grounds.

“It’s amazing to see these species return to the area,” says Nero. “We took their freshwater pathway from them, and now we’re returning it to them.”

This article was originally part of a longer article published in 41°N. It is reprinted here with permission. Read the full article on the 41°N website.

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