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SEPT 51 FEB 52 AUG 52 SEPT 52 OCT- NOV 52 



Figure 13. Abundance of Yellowf in at 150° W. Loa- 

 gitude on Successive Cruises. While the results of succeeding 

 fishing surveys are consistent in most respects and show the same 

 rich zone near the Equator , some of "the details are puzzling. Here 

 we have grouped the results of successive surveys along 150° and 

 155° W, longitude. You can see that a downward trend ija catch 

 rate is suggested and superimposed on this are fluctuations from 

 one cruise to another. These fluctuations maybe the result of the 

 spurts and halts in the oceanographic production line mentioned a 

 few pages back. It is less easy to see why there should be a down= 

 ward trend. The fish of the more recent trips, however, have 

 been larger as well as fewer and we may be witnessing the passing 

 of a successful year class. If so, the numbers should go up again 

 with another successful spawning. We are hopeful that studies of 

 a biological nature, such as those related to larval abundance and 

 distribution, nnay yield clues concerning these fluctuations. 



14 



