Intruders in Our Waters: Neogobius melanostomus Environmental Impact and eDNA Presence in the Mohawk and Hudson River

The round goby (Neogobius melanostomus) is an invasive benthic fish species native to the Black and Caspian seas in Eurasia. This species was first detected in the United States in 1990 in the St. Clair River, Michigan. This species has demonstrated remarkable phenotypic plasticity allowing them to successfully inhabit various aquatic habitats, including rivers, streams, and estuarine environments. The presence of the round goby in New York State was first recorded in 2014 within the New York State Canal System in Rome, NY. Since this discovery, they have moved eastward throughout the Mohawk River and into the Hudson River confluence and beyond. Although there isn't a sufficient population of round goby in the Mohawk and Hudson River confluence to cause any ecological implications yet, efforts have been made to limit their further spread, including in the Upper Hudson region through the use of "double draining" in the lock system. This study aims to analyze the presence and distribution of round goby using environmental DNA (eDNA) in the Hudson and Mohawk Rivers and observe if there is any correlation with various water quality parameters. Water samples were collected from nine sites across the Hudson and Mohawk Rivers over eight weeks during the summer of 2024. Samples were analyzed using quantitative PCR (qPCR) with the ReesCOI assay for round goby detection. Water samples containing eDNA were collected, and water quality analysis was conducted in-situ using the YSI Pro Digital Multimeter. Samples were then extracted for qPCR analysis using the Qiagen Blood and Tissue Kit protocol (without Bead-beating) at SUNY ESF and quantified using the QuantStudio3 Applied Biosystems thermocycler. Round goby eDNA was most prevalent in Mohawk and Hudson sites near the confluence as these areas had the highest detection frequency; this region also reports to high native fish counts. From this we can observe if there are any correlations between eDNA and water quality, canal lock locations as well as basin characteristics. Detection of round goby populations using eDNA will contribute to the diminishing of their potential influences early on in the Mohawk and Hudson River. This study will help in the development of management strategies for limiting the continuing spread and migration, as well as the ecological impact of this species in New York's freshwater ecosystems.