The dataset includes four seperate files of data for a project that examined the strontium isotopic composition of otoliths of Clear Lake Hitch. Otoliths examined in this study were from randomly-sampled individual Clear Lake Hitch that recruited into the adult population in Clear Lake. The fish were collected in June and July 2017. Strontium isotopic composition (87Sr/86Sr ) in otoliths was determined with a multicollector LA-ICP mass spectrometer (LA-ICMPS; Nu Plasma HR, Nu Instrument, Inc.) interfaced with a Nd : YAG 213-nm laser (New Wave Research UP213) at the University of California, Davis. Fish capture and size data are in the file Clear Lake Hitch Otolith Data_FISH. Otolith increment data are in the file Clear Lake Hitch Otolith Data_INCREMENT. Strontium isotopic data are in the file Clear Lake Hitch Otolith Data_STRONTIUM. Laboratory standard data are in the file Clear Lake Hitch Otolith Data_STANDARD.