Archived blood samples collected during common bottlenose dolphin health assessments in the northern Gulf of Mexico from 2013 to 2018 were analyzed by RNA-seq to support and enhance the assessment of animal health. The transcriptomic data were analyzed in conjunction with the substantial pool of health and environmental data collected during health assessments to investigate the utility of transcriptomic data in overall assessment of dolphin health and/or as markers of specific health concerns. Overall design: Illumina based RNA-seq analyses were carried out on RNA extracts of whole blood from 76 archived samples using the Tursiops truncatus NIST Tur_tru v1 genome as a guide. Samples were collected in Barataria Bay, LA (n=60) or Sarasota Bay, FL (n=16) from 2013-2018. Samples from Sarasota Bay served as a reference population that had not been exposed to substantial oil, whereas the samples from Barataria Bay come from a population directly impacted by the Deepwater Horizon oil spill.