The goal of this study was to examine the impacts of long term exposure to ocean acidification treatment on the methylation and gene expression in the gills of juvenile Dungeness crab. Wild caught megalopae from the Puget Sound, Washington were reared under ambient (7.8) and low (7.2) pH conditions for 11 months. Gill tissue was collected and DNA extracted for evaluation of methylation using MBD-seq, and RNA extracted for gene expression analysis using RNA-seq.