AHLSTROM: KIND AND ABUNDANCE OF FISH LARVAE 



Figure 2. — Location of monitoring pattern (large solid circles), occupied between multivessel EASTROPAC cruises 

 at 2-month intervals by David Stai-r Jordan, and of zig-transect pattern (triangles) occupied by Oceanographer 

 during November 1967, superimposed on ETP II pattern. 



As on ETP I, this net was paired in an assembly 

 frame with a finer-meshed 0.5-m net. Each tow 

 attempted to obtain a uniform sampling of zoo- 

 plankton in the water column between the sur- 

 face and approximately 200-m depth. The net 

 assembly was lowered to depth by paying out 

 300 m of towing cable and then retrieved at a 

 uniform rate. The depth reached by the net was 

 estimated from the angle of stray (departure 

 from the vertical) of the towing cable. The av- 

 erage depths of haul taken by the three research 

 vessels are summarized in Table 1. Only slightly 



over two-thirds of the hauls were lowered to 

 depths of 200 m or more and about one-eighth 

 were taken at depths shallower than 180 m. 

 Based on variation in depths sampled, speed of 

 hauling was controlled less consistently on ETP 

 II as compared with ETP I. 



Four plankton collections were made each day 

 with the paired net-assembly, at about 6-hr in- 

 tervals. Timing of hauls was not coordinated 

 between research vessels (Table 2), Usually 

 Rockaway spaced the four hauls at approximate- 

 ly 0500, 1030, 1700, and 2300; hauls from Wash- 



1155 



