FISHERY BULLETIN: VOL. 75. NO. 2 



SIPHONOPHORA THALIACEA 



CTENOPHORA 



AMPHIPODA 



FIGURE 4. — Charts of the geographical distribution of biomass for each of the taxa based on logarithmic means for 

 each standard zone (see Figure 1 ) for all the CalCOFI cruises for 1955-59. Contours are drawn at levels correspond- 



The ranks are given in Table 4, and the value of 

 Spearman's rank correlation coefficient between 

 the two ranks is + 0.806 which is significant at the 

 0.19c level. 



Figure 6 shows graphs of the first principal 

 components of the analyses for each taxonomic 

 category with the categories ranked in the same 

 order as in Table 4. All the northern and inshore 

 categories, down to Crustacea larvae in Figure 2, 

 show the same form of year-to-year fluctuations in 

 biomass as do the zones, with relatively high 

 biomass in 1955 and 1956 and low biomass in 1958 

 and 1959. The remaining categories show some 



features of this pattern with only Cladocera 

 showing a negative relationship. 



These results suggest that whatever influence 

 or influences are responsible for the fluctuations 

 in the plankton either have their origin in the 

 north of the survey area or have a greater effect on 

 those categories with northern patterns of distri- 

 bution. It is, at least, fairly safe to infer that there 

 is some commonality between the influences 

 which determine geographical distribution and 

 those which are responsible for the form of the 

 year-to-year changes in biomass. 



The years from 1955 to 1959 were deliberately 



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