PLANKTON CONCENTRATION — ^EASTERN & TROPICAL PACIFIC 383 



TABLE I 

 Beginning Time of Sampling at Stations Shown in Figure 3 



In Figure 6 the plankton volumes from both types of net hauls are 

 shown in relation to the isotherms at the eastern crossing. In the ab- 

 sence of complete hydrographic data and somewhat too great spacing 

 of the stations, it is not possible to say with certainty just what portion 

 of the current system supports the greatest plankton volumes, but the 

 structure of the water mass and the volumes obtained suggests a hjgh 

 plankton concentration at the southern edge of the counter current. 



In contrast to the plankton-rich waters of the equatorial currents, 

 there was a dearth of plankton along much of the ship's course north 

 and northwest of the Fiji Islands and from these islands westward below 

 the equator through the Tonga, Samoa, Society and Marquesas Island 

 groups. The "Dana" also found low plankton volumes in much of this 

 area (Jaspersen 1935). 



Increased plankton volumes were again obtained in the eastern 

 South Pacific over the Easter Island Rise between about 10° to 16° S, 

 113° to 124° W (Figs. 3-4). Correlated with this more abundant plank- 

 ton, there was a marked increase in the number of schools of flying fish 

 and of squids. 



Bibliography 

 Graham, Herbert W. 1941. Plankton production in relation to the character 



of water in the open Pacific. Jour. Mar. Res. 4(3): 189-197. 

 Jaspersen, P. 1935. Quantitative investigations on distribution of macro- 

 plankton in different ocean regions. "Dana" Report No. 7. 

 King, J. E. and J. Demond. Zooplankton abundance in the central Pacific. 



U.S. Fish and Wildlife (in press). 

 Progress Report California Cooperative Sardine Research Program. State of 

 California Department of Fish and Game Marine Research Committee 

 1950 and 1952. 

 ToKiOKA, Takashi. 1942. Plankton abundance in Twayama Bay and waters 

 surrounding Palau Islands. (Kagaku Nanyo) 5(1): 44-55 (In Jap- 

 anese) . 



