366 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



1954b; Stroup, 1954; Murphy and Shomura, 1955; 

 and Iversen and Yoshida, 1956). 



For the most part, sampling was done along 

 north-south lines since in this portion of the cen- 

 tral Pacific the current flow is zonal, i. e., tends to 

 be parallel to the Equator. With this type of 

 circulation, it was believed that maximum infor- 

 mation from hydrograpliic and plankton observa- 

 tions would be obtained with station lines normal 

 to the flow. The northernmost station was lo- 

 cated at 3r54' N. latitude, 119°46' W. longitude 

 and the southernmost station at 8°58' S. latitude, 

 121 °28' W. longitude. In an east-west direction 



the sampling extended from 110° W. to the 180th 

 meridian, a distance of 4,200 miles. 



The majority of the collections were taken with 

 1-meter (mouth diameter) nets with body (front 

 and middle sections) of 30XXX silk grit gauze 

 (apertures averaging 0.65 mm. in width), rear sec- 

 tion and bag of 56XXX silk grit gauze (apertures 

 averaging 0.31 mm. in width). For comparative 

 purposes 6 hauls were made on cruise 15, Hugh M. 

 Smith, with a 1 -meter net of 56XXX grit gauze 

 body and 72XXX grit gauze (apertures averaging 

 0.21 mm. in width) rear section and bag. 



Oblique hauls of approximately 30 minutes' 



Figure 1. — Plankton-station position.s of Hugh M. Smith cruises il (May-July 1951), 11 (August-October 1951), and 14 



(January-March 1952). 



