-100 



TO 58- I (SCOT) 

 APRIL- JUNE 1958 



NORTH LAT 5°-23° 

 INSHORE a OFFSHORE 



"1 (RELATIONSHIPS SIGNIFICANT) 



ZOOPLANKTON, ML/1000 M' (Z) 



ZOOPLANKTON. ML/1000 M' (Z) 



M= 13 6 

 Z = 121 7 



N= 13 



I I I I ■ ■ ' 



TO 59-1 

 JAN -FEB 1959 



NORTH LAT e"-23" INSHORE 



(RELATIONSHIPS NOT SIGNIFICANT) 



ZOOPLANKTON. ML/IOOOM' (Z) 



ZOOPLANKTON, ML/1000 M' (Z) 



Figure 13.--ChlorophylI a and zooplankton at noon stations, and zooplankton and micronekton at night stations: TO-58-1 (SCOT) and TO-59-1. 

 The lines in the upper panels indicate functional or structural relationships, not least-squares regressions. 



supply is considered. The data on tuna abun- 

 dance are on abundance as apparent from 

 the records of the baitboat fishery. The 

 Inter-American Tropical Tuna Commission 

 has compiled such data in terms of mean 

 catch per standardized day's fishing for each 

 1 -degree rectangle for each quarter-year 

 in the period 1951-59 (Shimada and Schaefer, 

 1956; Griffiths, 1960; Alverson, I960). 

 More recently the data were made avail- 

 able by 1 -degree rectangles and months 

 and have been particularly useful in this 

 form. 



Baja California 



Occurrence of yellowfin and skipjack in 

 Pacific coast waters of Baja California is 

 normally confined to the warmer months. 

 This is well-known, and dependence of distri- 

 bution upon temperature in near-surface waters 

 has been generally surmised. 



This belief appears fully justified as far as 

 the limit of distribution is concerned, for 

 reasons evident in figure 14. The lower part 

 of this figure shows (a) the northern limit of 



37 



