VARIABILITY IN TRAWL CATCHES 



165 



Table 12. — Frequency of occurrence of species with different 

 numbers of individuals and expected frequency of occur- 

 rence on the hypothesis of a logarithmic series distribution, 

 1948-60— Continued 



b. Depth Zone II 



c. Depth Zone III 



Table 13. — Frequency of occurrence of species with different 

 numbers of individuals and expected frequency of occur- 

 rence on the hypothesis of a logarithmic series distribution, 

 depth zones I— III 



a. Year 1948 



b. Yeah 1949 



Table 13. — Frequency of occurrence of species with different 

 numbers of individuals and expected frequency of occur- 

 rence on the hypothesis of a logarithmic scries distribution, 

 depth zones l-lll — Continued 



c. Year 1950 



Table 14. — Individuals (N), species (S), indices of diversity 

 (a), and variance of a by depth zones and years 



Table 15. — Distribution of number of species caught per 

 tow in each year (A) and the same with elimination of the 

 first three tows following a change of net (B) 



