The daily boat tracks of the 1997-2001 summer skiff-based double-sampling surveys were recorded to an onboard computer using the custom survey software RECORD (John I. Hodges, FWS-MBM-Alaska, retired). The tracks were recorded by capturing the skiff’s location from a GPS every five seconds as long as the software was running. The software was started at some time between the boat’s engine start and the start of the survey, and was shut down at some time between the end of the survey and engine shut-down. The tracks may thus include the boat’s travel to and from the home base. Note that the following boat tracks are missing: all 1997 tracks; one track on 08/12/1998; one track on 08/08/2001; one track on 08/09/2001.