Two age-classes of Pacific oysters (Crassostrea gigas), i.e. young and adult, were used as sentinels to monitor mortality in the Baie des Veys (Normandy, France) from mid-April to October 2014. Oysters were deployed at 39 sites spread over a 37 km² surface area inside and outside of the shellfish farms. Each site was visited 9 times (12-15 May, 13-16 June, 26-30 June, 12-18 July, 27-29 July, 11-14 August, 25-27 August, 9-12 September, 16 October 2014) during spring tides. For young oysters, cumulative mortality obtained in September is provided. For adult oysters, cumulative mortality is provided for 2 periods: from mid-April to mid-July (Period 1) and from mid-July to October (Period 2). A validated 3-D hydrodynamic Model for Applications at Regional Scale (MARS-3D) coupled with a biogeochemical model (ECOMARS-3D) was used to generate high frequency data of seawater temperature, salinity, chlorophyll a concentration (derived from phytoplankton) and hydrodynamic connectivity to oyster farms and to the mouths of the channel rivers at the 39 sites. For seawater temperature, salinity and chlorophyll a, the minimum, maximum and mean values of hourly data are provided for the whole study period as well as the mean of daily mean or median of daily median for Periods 1, 2 (used for adult oysters) and the period from mid-April to September (used for young oysters). Hydrodynamic connectivities to river channels (Carentan and Isigny) and shellfish areas (Grandcamp and Utah Beach) were estimated in February, May and August 2014. This database is part of the ANR GIGASSAT project No. ANR-12-AGRO-0001.