ABSTRACT 



This report presents the biological, environmental, and meteorological data from four 

 consecutive cruises, October 1957 to June 1958, in the part of the southeastern Pacific Ocean that 

 is centered in the Marquesas Islands. Primary mission of these cruises was to define the season of 

 greatest availability of surface tuna schools in the Marquesas area. 



Tabulated data include the following: observations of weather, water color, and water 

 transparency; determinations of zooplankton volumes, surface salinities, and phosphates; observa- 

 tions at bathythermograph lowerings, tuna school sightings, surface fishing operations, and baitfish 

 surveys . 



