This data release includes Lake Ontario prey fish data including species captured, relative abundance, spatial distribution, size structure, and age data from the April or spring prey fish bottom trawl survey, 1997 and 2021. Data from 1997 - 2015 are from U.S. waters of Lake Ontario while data from 2016 - 2021 include both U.S. and Canadian waters of Lake Ontario. Details about the vessel and gear descriptions, sampling protocols, and catch processing protocols can be found in the Process sections of this metadata. Portions of this data release follows the data model of the USGS Great Lakes Science Center Research Vessel Catalog (RVCAT). The trawl data included in this data release are a subset of the larger RVCAT data base. We note the data included at the time of this release were not yet available in the overall RVCAT data release. The RVCAT data can be found here: https://doi.org/10.5066/F75M63X0.