NOURISHMENT OF CENTRAL PACIFIC STOCKS OF TUNA 137 



specific example, and zonal aspect by averages exemplifying a particu- 

 lar period of the year. For neither aspect have I indicated the varia- 

 bility in location and magnitude of the various elements of the system. 

 Likewise there are neglected the peculiarities which crop up in each set 

 of data collected. This portrayal therefore is certainly much distorted 

 in the direction of over-simplification and most probably distorted to 

 an unknown degree in the direction of specific peculiarities of the par- 

 ticular sets of data employed. When more complete data are at hand 

 and when there has been a more thorough study, a different and pro- 

 bably more complex concept will be necessary. 



In the meantime there appears to be very complete agreement in 

 the gross features of equatorial circulation, of plankton distribution, 

 and of fishing ground location as to time, place, and relative magni- 

 tude. The correspondence is such as to leave little doubt that the 

 yellowfin tuna stock south of Hawaii owes its existence to and is nour- 

 ished by the equatorial current system. 



Perhaps of interest equal to the facts themselves is the demonstra- 

 tion that a rich fishing ground may be discovered through the scientific 

 study of the particular features of ocean circulation pertinent to the 

 existence of fish stocks. 



It is, of course, obvious that the attainment of the present degree 

 of understanding has resulted from the participation of a considerable 

 number of persons ranging in specialization from expert fishermen to 

 senior scientists united in a concerted drive toward a common objective. 

 Milner B. Schaefer, John L. Kask, and Donald L. McKernan have suc- 

 cessively led the scientific team. Townsend Cromwell, until recently, 

 has been in charge of the oceanographic program; Joseph E. King has 

 been the chief researcher on plankton and on the food of tuna; while 

 Fred C. Cleaver initiated, and Garth I. Murphy has carried on, the 

 longline fishing surveys. I am especially grateful to our present ocea- 

 nographer, Thomas S. Austin, for invaluable assistance in assembling 

 the materials for this report. 



