European Seabirds At Sea (ESAS) assembles offshore monitoring data on seabirds and marine mammals. This international database mostly includes data from the North Sea, yet large parts of the northeastern Atlantic Ocean are covered as well. It finds its origin in the 'Seabirds at Sea' project, which was initiated in 1979 following the discovery of major oil potential in the North Sea and an urgent need to gain more knowledge on the occurrence and distribution of seabirds in their offshore habitat. This led to the execution of large-scale ship-based surveys across the North Sea using a standardized data collection method and a first European-wide data assembly in 1991.

ESAS data are collected by various partners during aerial or ship-based surveys at sea and according to a methodology that allows to calculate georeferenced seabird densities. Standard practice further implies collecting as much information as possible on animal age, plumage and behaviour as well as observation conditions and distance to the observed individuals. As part of the WOZEP research project, ESAS data were migrated in 2022 from its former host JNCC (UK) to ICES. The ICES infrastructure allows partners to submit new data and users to download or request data.