We investigated whether elevated rearing temperature through larval development of Delta smelt adjusted upper thermal tolerance limits (acclimation) in Delta Smelt, whether upper thermal tolerance and plasticity (acclimation ability) differed between fish with old or recent hatchery ancestry (high or low domestication index; DI), and temperature and DI effects on liver transcriptome and methylome patterns. This dataset contains global methylation levels from CpG count matrices for every 100 individuals, generated using the program Bismark. Each file corresponds to a single individual fish. Within each file is a matrix of loci (chromosomal and SNP location in the Delta smelt genome) and whether the site is methylated or not. The file identification corresponds to the fish ID. Metadata for the fish (including treatment conditions) is found in the file: methyl_metadata.xlsx. All procedures were approved by the UC Davis Institutional Animal Care and Use Committee (IACUC Protocol #21915).

We reared Delta Smelt from embryos until 143-151 dpf at either 15 °C or 18 °C. We then dissected livers and flash-froze them. We performed whole-genome bisulfite sequencing on ~100 livers. We used the program Bismark to create CpG site matrix files for each individual. These files were used as input in the DMRichR package to look for differential methylation patterns.