Southern California (Point Conception to Coronado 

 Islands, Mexico) 



During the surveys, temperatures off southern California ranged 

 from 9.4° to 23.3°C (49.0°-74.0°F). The coldest temperatures 

 were in areas near Point Conception and the Santa Barbara Channel 

 Islands, and the warmest temperatures occurred offshore southwest 

 of Dana Point . Mean temperatures ranged from 1 2 . °C (55 . 1 °F) off 

 the Point Conception-Santa Barbara Channel Islands area, to 20.8°C 

 (69.5°F) off Dana Point. 



Yellowtail.— The yellowtail is a pelagic coastal migratory species 

 and commonly ranges from the southern tip of Baja California, Mex- 

 ico, to near Point Conception, Calif. It is one of the most important 

 sport fishes in southern California and an important commercial spe- 

 cies in Mexico. The major sportfishing areas for yellowtail at the 

 northern portion of their range are the Coronado Islands, Mexico, the 

 kelp beds off Point Loma and La Jolla, Calif., and Catalina Island. 

 These fish are caught off southern California in quantity only during 

 the summer migration north from off the Baja California coast. The 

 distribution of yellowtail catch and temperature off southern Califor- 

 nia (Fig. 5) shows that the catch temperature mean is higher than the 

 sea surface temperature mean in all months except September, Octo- 

 ber, and November. These results indicate that greater catches are 

 made in months when temperature is above the mean. 



Figure 5.— Distribution of yellowtail catch off southern California and north- 

 ern Mexico by month, August 1963- July 1968, for total catch, catch tempera- 

 ture, and sea surface temperature range and means, and the standard 

 deviations about the means. 





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Figure 6.— Catch and temperature data by block area for yellowtail caught off 

 southern California. 



Figure 6a and b give the following information by block area for 

 those areas having a catch of 1 ,000 or more yellowtail during the sur- 

 vey period: the month of the greatest total catch; temperature at 

 which most yellowtail were caught; the mean catch temperature; and 

 the number of yellowtail in the sample. The yellowtail 's seasonal 

 migration northward can be detected by examining the dominant 

 catch by block area by month. Near the Coronado Islands (block 

 916,), the first catch peak is recorded in June (block 860). The catch 

 peak is also in June off Point Loma and La Jolla; however, yellowtail 

 is taken for a long period during the summer months in this nearshore 

 area. For block areas 761 and 762 north of Catalina Island, the peak 

 catches are in June and July. Fishing along the coast near the greater 

 Los Angeles area (block 720) peaks in October, as it does along the 

 coast west of Los Angeles and off Santa Barbara. There is evidence 

 of a late summer southward migration, as a second catch peak occurs 



off the Coronado Islands in September. The shift of the catch temper- 

 ature mean to less than the sea surface temperature mean indicates 

 greater catches during the late summer months, when temperatures 

 are slightly lower than the mean. 



Graphs of the temperatures and catches of yellowtail in the three 

 leading block areas (916, 860, 761) are provided in Figure 7a, b, c. 

 These graphics show the distribution of catch by temperature and by 

 month for catch, temperature at which most yellowtail were taken, 

 monthly mean catch temperature, and standard deviation of the mean 

 catch temperature. 



Pacific bonito.— Bonito is a species that is known to migrate con- 

 siderable distances along the coasts of Baja California, Mexico, and 

 into southern and central California. Like the yellowtail, these fish 



