FISHERY BULLETIN: VOL. 87, NO. 3, 1989 



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Factor 1 



Factor 1 



Figure 3. — (A) Loadings on the first two factors from a principal components analysis of size-standardized morphometric traits 

 measured on 147 Pacific sardines; 10 = interorbital width, VE = snout to vent length, DO = snout to dorsal-fin origin, AL = 

 anal-fin base length, CP = caudal-peduncle depth, HW = ma.ximum head width, BD = minimum body depth, OR = snout to orbit 

 length, OP = snout to operculum length, MX = snout to maxillary length, SO = snout to supraoccipital length. (B) Scores for 

 individual sardines on these first two factors. Open triangles, solid line: SOCAL; open inverted triangles, dashed line: MAGDA. 

 Other populations are sohd circles, TOMAL; solid triangles, MONTE; open circles, GUAYM ( see Figure 1). 



Bight vs. Monterey Bay and Magdalena Bay vs. 

 Guaymas) also show variation in head : body-size 

 allometry. A standard length range of 192-240 

 mm defines a subset of the Monterey Bay sample 

 comprising 17 individuals whose mean length is 

 identical to that of the 30 southern California 

 specimens. DFA of log-transformed variates 

 takes two steps to produce significant between- 

 gi-oup variance (F = 13.344, P « 0.001; 2, 44 

 df) and an average percent correct assignment in 

 a posteriori classifications of 77% CRible 4A). The 

 two characters used in the classification func- 

 tions are interorbital width and head width 

 (Table 4A). Between subsets of similarly sized 

 fish (145-162 mm) from Guaymas (A^ = 37) and 

 Magdalena Bay (N = 11), DFA of nine log-trans- 

 formed variates (three were discarded to keep 

 the number of variates less than N = 11 for 

 Magdalena Bay) produces significant variance in 

 three steps (F = 17.568, P « 0.001; 3, 44 df) 

 and 90% correct classification (Table 4B). Maxil- 

 lary length, interorbital width, and length of 

 anal-fin base contribute to the classification func- 



tions for these two Mexican populations (Table 

 4B). 



Engraulis mordax 



Genetic Variation Within Populations 



Electrophoretic variation was detected in all 

 northern anchovy proteins examined except 

 ALDO and CK. From this variation in protein 

 phenotypes, we infer that our samples of north- 

 ern anchovy populations contain substantial 

 levels of individual genetic variation (Table 5). 

 Over the 39 loci examined, the average number 

 of alleles per locus per population is 1.61 ± 0.02, 

 ranging from 1.49 ± 0.13 in the inshore Half 

 Moon Bay sample to 1.72 ± 0.16 in the offshore 

 Santa Cruz sample. Proportions of polymorphic 

 loci per population range from 33.3% in the in- 

 shore Half Moon Bay sample to 46.2% in the 

 middle station of the Santa Monica Bay transect; 

 mean P over the nine samples is 39.8% (95% 

 C.L.: 37.2-42.5%). Average expected hetero- 



660 



