The data consists of a compilation and review of both published and unpublished records, between 1838 and 2006, from the Irish coastal and territorial waters. The data have all been reviewed and more recent sightings were validated by Gabriel King.
Some biological records have more precise location information than others. Often they are recorded using national grid references, which identify which 50km, 10km, 2km, 1km or 100m square they occur in. For this dataset, all records (989) are at the 100m resolution.
Often the actual day on which records were made is not known precisely. However, they may be known to be within a particular month or year. For 709 records the date precision is "day range", for 276 records the date precision is "day", and for 7 records the date precision is unknown.