This dataset contains d13C and d15N stable isotope data from northern hemisphere rorqual whale (Balaenoptera) baleen taken from our collections. This includes data from the baleen of the Hintze Hall blue whale. The data has been used in various research papers. Additional data allow the analyses in these papers to be carried out and mostly encompass environmental datasets or the outputs of various simulation models. **Note that if trying to link these data to analyses in GitHub, an update to this site has changed all "." in column headers to "_". These will need to be changed before the code will work. Apologies.**