Officials are crediting the removal of the Hughesville Dam with bringing the American shad back to the Musconetcong.
New Jersey was a British colony the last time the American shad swam in the Musconetcong River.
Colonialists nearly 300 years ago dammed the Delaware River tributary, which straddles the border of Warren County's Pohatcong Township and Hunterdon County's Holland Township just south of Phillipsburg.
The dams made the Musconetcong impassable for the shad, which live most of their lives in the Atlantic Ocean but swim up the Delaware River and smaller rivers that empty into the Delaware each spring to spawn.
The Hughesville Dam, a few miles from the confluence of the Delaware and Musconetcong rivers, and several other dams farther upstream were built based on the needs of the time, but no longer serve any purpose.
The Musconetcong Watershed Association, in a collaborative effort with state and federal agencies, last summer started an estimated $1.5 million project to remove Hughesville Dam, which once generated hydropower. The work was completed in November.
The dam's removal restored the Musconetcong River to a free-flowing stream for five miles before it spills into the Delaware River.
The watershed association reported Monday that a fisheries biologist with the New Jersey Division of Fish and Wildlife found shad swimming upstream from the site of the Hughesville Dam.
American Shad (Courtesy of Pennsylvania Fish and Boat Commission) Alan Hunt, the association's executive director, calls it remarkable that the shad returned in the first season since the dam's removal.
The Hughesville Dam is one of several dams that have either been removed in recent years or are slated for removal in the coming years along the Musconetcong River.
Eric Schrading, of the New Jersey field office of the U.S. Fish and Wildlife Service, says in a statement that the shad's return "provides validation that dam removal opens rivers like the Musconetcong to passage of migratory fish."
The next Musconetcong dam targeted for removal is the 32-foot high Warren Glen Dam, less than a mile farther upstream. It is the largest dam in the Musconetcong River. By comparison, the Hughesville Dam was 15-feet tall.
Work on that dam's removal is expected to start in 2018. The watershed association on Monday didn't immediately have a cost estimate available for that project.
Although the Hughesville Dam was built in 1889, other dams that have since been removed downstream date back nearly 300 years. Among them were the remnants Riegelsville Dam, which were removed in 2011. All contributed to impeding the shad's migration into the Musconetcong, the watershed association says.
The dam-removal projects were considered significant enough to warrant a September 2016 local visit from then-U.S. Secretary of the InteriorSally Jewell. She toured the Hughesville Dam removal project during that visit.
Obama official tours dam removal project
The American shad carries a special place in the history of the Lehigh Valley. Shad runs up the Delaware River used to be so abundant fishermen waited up to 30 minutes at a Easton and Phillipsburg boat launches just to get on the river, but the populations started depleting several decades ago.
The confluence of the Delaware and Lehigh rivers have long been the site of an annual shad fishing contest in the spring.
Nick Falsone may be reached at nfalsone@lehighvalleylive.com. Follow him on Twitter @nickfalsone. Find lehighvalleylive.com on Facebook.