Marine mammal observations conducted during US National Science Foundation geophysical research cruises in the global oceans from the platforms Maurice Ewing, Marcus G. Langseth, Thomas G. Thompson, and the R/V Knorr from 28 May 2003 to 25 August 2009 (NCEI Accession 0083783)

All marine mammals and sea turtles that were visually observed during a marine geophysical survey were recorded to: 1) determine whether a mitigation measure needed to be implemented during the survey; 2) determine the potential number of animals exposed to seismic sounds. During periods when no marine mammals were observed, the vessel location and the environmental conditions were also recorded approximately every 30 minutes whenever a Protected Species Observer was on watch (during daylight hours).