The Sea Watch Foundation has been collecting both effort-based and non-effort-based sightings data of marine mammals and other megafauna since the late 1960s. The main area of coverage is the waters around Britain and Ireland but with some surveys elsewhere. Data come from platforms ranging from small to large vessels either on dedicated survey or platforms of opportunity, and from coastal land sites. Data collected include environmental conditions, marine traffic, and seabird associations. Sighting records come from all types of marine user from marine mammal biologists to citizen scientists and members of the public. All sightings are checked, and species ID validated from still or video images and/or descriptions, except in those cases where persons are known, experienced, observers.