Geography, not human impact, is the predominant predictor in a 150-year stable isotope fish record from the coastal United States

•We explore human impacts on coastal food webs of the continental United States.•Stable isotopes measured in modern and archival fish (~1904) were linked with indicator variables.•Random forest analyses indicated that geography was the best predictor of fish isotopes.•While human-created nitrogen is an important source to coastal food webs, so is location.