Supplementary Information Table 1. Fossil otolith data. Metadata.

Column A: otolith_id - unique number assigned to each otolith recovered in this study [no units]

Column B: core_type - BC is box core; KC is Kasten Core [no units]

Column C: subcore_number - number the subcore from which otolith was extracted [no units]

Column D: transverse_section_number - number of the transverse section within a subcore from which otolith was extracted [no units]

Column E: otolith_number - unique number of otolith in a transverse section [no units]

Column F: level_alteration - level of alteration (2, least altered, to 10, most altered)

Column G: year_ad - age of otolith [year AD]

Column H: group - classification model (group 1 used random forest analysis with morphological and elliptical Fourier features; group 2 used discriminant function analysis with morphological, elliptical Fourier and element features) [no units]

Column I: class_g2 - classification of group 2 using random forest analysis with morphological and elliptical Fourier features [no units]

Column J: class_g1 - classification of group 1 using discriminant function analysis using discriminant function analysis with morphological, elliptical Fourier and element features [no units]

Column K: class_expert - classification by expert opinion [no units]

Column L: li_ca - lithium 7 / calcium 48 element ratio of whole otolith [mol mol^-1]

Column M: mg_ca - magnesium 25 / calcium 48 element ratio of whole otolith [mol mol^-1]

Column N: mn_ca - manganese 55 / calcium 48 element ratio of whole otolith [mol mol^-1]

Column O: sr_ca - strontium 88 / calcium 48 element ratio of whole otolith [mol mol^-1]

Column P: ba_ca - barium 138 / calcium 48 element ratio of whole otolith [mol mol^-1]

Column Q: na_ca - sodium 23 / calcium 48 element ratio of whole otolith [mol mol^-1]

Column R: k_ca - potassium 39 / calcium 48 element ratio of whole otolith [mol mol^-1]

Column S: area_mm2 - area of otolith [mm^2]

Column T: perimeter_mm - perimeter of otolith [mm]

Column U: axis_major_mm - major axis length of otolith [mm]

Column V: axis_minor_mm - minor axis length of otolith [mm]

Column W: ed_mm - equivalent diameter of otolith [mm]

Column X: roundness - roundness of otolith (1 circle to 0 line) [dimensionless]

Column Y: aspect_ratio - axis_major_mm axis_minor_mm^-1 [dimensionless]

Column Z: extent - area of otolith (area of bounding box)^-1 [dimensionless]

Column AA: ellipticity - (axis_major_mm - axis_minor_mm) (axis_major_mm + axis_minor_mm)^-1 [dimensionless]

Column AB: eccentricity - (distance between ellipse foci) axis_major_mm^-1 [dimensionless]

Column AC: cnva_mm2 - convex area [mm^2]

Column AD: solidity - area_mm2 cnva_mm2^-1 [dimensionless]

Columns AE:BG: x2 - x30 - elliptical Fourier descriptors in X dimension for harmonics 2 - 30 [dimensionless]

Columns BH:CK: y1 - y30 - elliptical Fourier descriptors in Y dimension for harmonics 1 - 30 [dimensionless]