In 2021, during routine fish monitoring, DEC Hudson River fisheries staff captured four invasive round gobies downstream of the Troy Federal Dam, marking the species’ first known presence in the Hudson. By the end of the year, DEC had documented 112 round gobies in areas as far south as Poughkeepsie, raising alarms about the potential ecological, recreational, and economic impacts on the river and its tributaries.

Round gobies are aggressive bottom-dwelling fish that reproduce rapidly and have voracious appetites, consuming small invertebrates, mussels, and the eggs of native species, including popular sportfish like smallmouth bass and walleye. Although the fish had already spread to several New York watersheds, including the Erie Canal and Mohawk River, the goby’s arrival in the Hudson raised concerns about their competition with native species, as well as their potential to spread diseases such as viral hemorrhagic septicemia (VHS) and avian botulism, seen in other Great Lakes regions.

Given the round goby’s disruptive potential, Hudson River marine biologists launched several initiatives to research the spread of goby and their potential impacts. Since 2022, biologists have been using environmental DNA (eDNA) sampling and other monitoring methods to track the spread of goby throughout the tidal Hudson River. Two ongoing studies in collaboration with SUNY Oswego are also exploring the threat of predation from goby on sturgeon and other migratory species (striped bass, American shad) and estimate changes in round goby population sizes using genetic techniques.

By 2023, research had expanded to include experiments on the ability of round goby to survive in brackish and saltwater environments. Studies led by Cornell University in collaboration with DEC focused on the species’ salinity tolerance, a key question for understanding how far the goby could spread in the Hudson River estuary and beyond, into marine environments like New York Harbor. The research revealed that the goby could seasonally survive in waters with salinity levels similar to those in the Harbor, suggesting that it could potentially colonize the entire Hudson River watershed and disrupt marine ecosystems.

A significant, collaborative management response also has also been implemented by DEC, the New York Power Authority, and the New York State Canal Corporation through the development of a rapid response plan aimed at preventing the spread of the goby through the Champlain Canal into Lake Champlain. DEC and USGS have been using traditional fish sampling techniques and eDNA to monitor the presence of goby in the Champlain Canal. The monitoring data are used to execute a series of adaptive actions as outlined in a trigger action response plan (TARP). The TARP includes various mitigation strategies, such as double draining locks and canal traffic restrictions, to reduce the likelihood of round goby reaching Lake Champlain.

DEC remains committed to monitoring and mitigating the spread of round goby in the Hudson River and its tributaries. With ongoing research, collaboration with partner agencies, and a comprehensive approach to invasive species management, DEC is working to protect the Hudson River and the communities that rely on it.