Round Goby captured in a North American estuary: status and implications in the Hudson River, New York

Round Goby Neogobius melanostomus , a non-native fish species to North America, has been rapidly expanding through the connected waterways of the Laurentian Great Lakes. Here, we document the eastward and southern expansion of Round Goby into the Hudson River, an iconic coastal estuary that drains to Long Island Sound and the Atlantic seaboard. In the summer and early fall of 2021, a population of Round Goby was documented in the tidal portion of the Hudson River during routine fish monitoring conducted by the New York State Department of Environmental Conservation. Over the course of monitoring in 2021, 112 Round Goby were collected between Albany, NY and Poughkeepsie, NY with the southernmost collection occurring approximately ~140 km downstream of invasion front as reported in 2020 within the New York State Canal System. Although Round Goby have previously colonized large rivers and streams in the Great Lakes watershed, there is little information about the invasion success and ecological impacts of Round Goby in estuarine environments in North America. The distribution and biological characteristics of the Hudson River Round Goby population are discussed as well as the potential ecological implications and areas of future research and monitoring for this range expansion.