324 



BULLETIN OF THE BUREAU OF FISHERIES 



Table 17. — Comparison of calculated length values, based on diameter (V) and anterior radius (ac) 

 with each other and with actual length values. The actual lengths are based on all available Bay 

 City herring {collected 1921, 192-2, and 1923), while calculated lengths are based on the scales of 

 these herring, all age groups and year classes being combined ' 



End of growth year. 



Actual length (K), in millimeters 



Calculated (K), in millimeters based on (V)... 

 Calculated (K), in millimeters based on (ac)..- 



Differeuce between (K) and (K on V) _. 



Difference between (K) and (K on ac) __ 



DilTerence between (K on V) and (K on ac) . .. 



125 (1,116) 

 112 (1,116) 



273 (14) 



+13 



' The number of specimens employed is given in parentheses. 



' As presumably only the large individuals of this age group matured or straggled along with the older mature flsh, this average 

 must be considered as being too high. 



Table. 18. — Comparison of actual length with calculated length based on diameter (F) and anterior 



radius {ac) of scales from Bay City herring ' 



' The numbers in parentheses indicate numbers of individuals employed. ' Herring collected Oct. 27 to Nov. 4, 1921. 



Length computations corroborate this conclusion. In Table 16 are given two 

 extensive series of computed lengths — the one derived from the measurements of 

 the diameter (F), the other from those of the anterior radius (ac) of the scale. The 

 average of the differences between the computations of the two series is given at the 

 bottom of the table for each year. In Table 17 these data are simimarized. That 

 is, the computed lengths for corresponding years are combined into one average, 

 irrespective of the age group or the year class to which the fish belonged. In Table 

 18 the computed lengths are arranged according to the year class to which the fish 



