FISHERY BULLETIN: VOL. 84, NO. 4 



larvae had been abundant since June (Fig. 4). Lar- 

 vae >15 mm long were found over the shoals near 

 station 3 in October and April (Fig. 5). Larvae longer 

 than 15 mm were taken in the channel from Novem- 

 ber through February, months with little or no 

 spawning. Large larvae and juveniles, which had ap- 

 parently overwintered, were present when spawn- 

 ing resumed in March and April. 



DISCUSSION 



Previous suggestions that northern anchovy 

 spawn in San Francisco Bay were based on the pres- 

 ence of small larvae (Eldridge 1977; Sitts and Knight 

 1979), juveniles (Smith and Kato 1979), or the 



spawning season in the California Current (Hubbs 

 1925). Anchovy eggs collected in this study provide 

 conclusive evidence that the northern anchovy 

 spawns in San Francisco Bay because eggs could not 

 drift upstream to station 5 or into South Bay as far 

 as station 1 or 2. Peak spawning based on the abun- 

 dance of eggs was May through September when 

 adult anchovies are known to be plentiful in the Bay 

 (Aplin 1967). 



Spawning in San Francisco Bay differed from an- 

 chovy spawning in the sea. Most spawning of the 

 central subpopulation of northern anchovy in the 

 California Current takes place January- April when 

 the 10 m temperature isl4°-16°C; not June through 

 October when water temperature is 16°-19°C 



Figure 4.— Length-class frequencies of larvae and juvenile northern anchovies for 



each month of the study. 



888 



