80r 



70 



60 



50 



uj 40 



30- 



20- 



10 



FISHERY BULLETIN: VOL. 70. NO. 3 



SPRING 



WINTER 



52 



53 



54 



55 



56 



57 



58 59 



YEAR 



60 



62 



63 



64 



65 



66 



Figure 12. — A time-series comparison of the annual total regional census estimates of 

 anchovy larvae as grouped by season of spawning. The highest line (solid circle) is 

 comparable to that found in Figure 10 and to the height of "A" in Figure 9. 



studies are found in Table 12. The primary ob- 

 jective of this study concerns the period of in- 

 crease from 1951 to 1966. Despite various tech- 

 nical deficiencies in the basic data, the years 

 1940, 1941, 1950, and 1969 are also estimated 

 in the section to follow. 



The first column of Table 12, Murphy's (1966) 

 sardine spawner biomass estimates, is repro- 

 duced without change. If those estimates are 

 changed by later studies, all other values in the 

 table must be adjusted. The important features 

 of Table 12 are 1) a regression estimate to de- 

 rive sardine spawner biomass estimates from the 

 regional census estimates of total sardine larvae; 

 2) a ratio estimate of anchovy spawner biomass 

 which is half the product of the anchovy: sardine 

 ratio and the sardine biomass; and 3) a regres- 

 sion estimate of anchovy spawner biomass de- 

 rived from the regional census estimate of total 

 anchovy larvae. 



The equation for a least squares estimate of 

 sardine spawner biomass and sardine total lar- 

 vae derived for this study is: 



Bs 



0.230L. — 0.057 



where Bs is the annual estimate of sardine 

 spawner biomass in thousands of short tons and 

 Ls is the regional census estimate annual total 

 of sardine larvae in numbers times 10*^ j^ the 

 years 1951-58, excluding 1953. The years 1953 

 and 1959 were eliminated as outlyers on a scatter 

 diagram when it was found that the assumption 

 of constant size distribution of larvae had been 

 violated. The equation was later simplified by 

 assuming a zero intercept to: 



Bs = 0.206L, 



The anchovy spawner biomass estimates were 

 derived from the ratio of anchovy: sardine larvae 

 and the Murphy sardine biomass estimate in the 

 following way: 



Ba = C 



La 



Bs 



where Ba is the ratio estimate of anchovy spawn- 

 er biomass, La is the regional census estimate 



870 



