pCO2 is the partial pressure of CO2 in a liquid or gas. In oceanography, it is used to investigate carbon dioxide (CO2) dissolved in the surface layers of the ocean in order to better understand changes in ocean carbon chemistry and ocean acidification due to enhanced atmospheric CO2. The RV Celtic Explorer has a pCO2 Underway System. pCO2 data was collected during the 2019 CE19005 Blue whiting acoustic survey on board the RV Celtic Explorer in March/April 2019 by the Marine Institute (MI) in the North East Atlantic Ocean. None