YELLOWTAIL 

 BLOCK NUMBER 915 



DISTRIBUTION OF CATCH 

 BY TEMPERATURE 



100 



7.2 



23.8 



20.0 



10.0 

 72 



1 * t| +1 



t| 



t ' I H 



STD. DEVIATION « 



RANGE 



7 



1,800 





. YELLOWTAIL 



1,500 



: 



1 BLOCK NUMBER 761 



1,200 



: ' 



A 



900 

 600 



- DISTRIBUTION 



OF CATCH 

 _BY TEMPERATURE 



\A 



300 



' 



s\r i a 







i,k 



i/ <j 



7.2 (»C) 10.0 

 23.8,- 



CATCH/ MONTH f 



I! 



It "I <t -I 



STD DEVIATION 



. 1 1— 1 1 1 1 1 1 1 1 



JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 



10.0 

 7.2 



U*MlV» 



fl 



+ t 



STD. DEVIATION ■ 



w 



Figure 7.— Distribution of catch by temperature and by month for catch, tem- 

 perature at which most yellowtail were taken, mean catch temperature and its 

 standard deviation, and sea surface temperature range and means for the three 

 major block areas having yellowtail catches. Top left, block 916; bottom left, 

 block 860; top right, block 761. 



show a large increase in their northern latitudinal distribution during 

 seasons when anomalous warm-water conditions exist in the north- 

 east Pacific (Radovich 1961). For all block areas in southern Califor- 

 nia where bonito are caught, the mean monthly catch temperature is 

 higher than the sea surface temperature mean, except for February, 

 October, and November (Fig. 8). August is the peak catch period, 



Figure 8.— Distribution of Pacific bonito catch off southern California and 

 northern Mexico by month, August 1963-July 1968, for total catch, catch tem- 

 perature and sea surface temperature range and means, and the standard devi- 

 ation about the means. 



and block 860 located off Point Loma/La Jolla in the San Diego area 

 has the largest recorded annual catch. Figure 9a and b give the fol- 

 lowing information for block areas having a catch of 20,000 bonito oi 

 more during the survey period: the month having the greatest total 

 catch, temperature at which most bonito were caught, the mean catch 

 temperature, and the number of bonito in the sample. 



