ABSTRACT 



This report describes the methods used and the results 

 obtained, without analysis, in observations made aboard the 

 research vessel Hugh M. Smith on the EASTROPIC expedition, 

 a cooperative oceanographic survey of the central and eastern 

 tropical Pacific, Septennber-December 1955. Information was 

 obtained on east-west gradients in temperature, salinity, phos- 

 phate , zooplankton, and forage-fish abundance. By means of 

 closing-net hauls a special study was made of the vertical dis- 

 tribution of zooplankton. In collaboration with the University of 

 Hawaii, carbon fixation and chlorophyll measurements were made 

 on the east-to-west leg of the cruise. A survey of tuna baitfish 

 was conducted in the Marquesas Islands. 



