Currently, the mapping products available from the database are based on ~60 datasets from 1906-2009 with over 260,000 records of seabird observations. These maps include representations of survey effort and bird detections. Effort was standardized into five minute equivalents so that both discrete and continuous transect data could be combined. This unit is essentially five minutes of survey effort from a vessel traveling 10 knots. Species data were prepared for occurrence maps by adjusting counts using these five minute equivalents. The resulting species maps are referred to as Naive occurrence maps because, although some effort standardization has been applied, there are no corrections for biases introduced by differences in survey methodology, observers, and species detectability. Click here for FGDC Metadata