386 BULLETIN OF THE BUREAU OF FISHERIES 



Table 52. — Comparison of computed lengths of each year of life of corresponding age groups of herring 

 collected at same locality but on different dates 



1 The last value of each horizontal row represents actual measurements of fish. 



The data of Tables 51 and 52 indicate that no consistent differences in size, rate 

 of growth, and age composition occurred in the 1924 herring samples taken at the 

 same locahty but on different dates. There are no indications in these tables that 

 the character of the herring stock of one locality changed during that period of the 

 spawning run under consideration. The computed values of length of Table 52 fur- 

 nish the most convincing evidence. The fluctuating differences that do occur may, 

 no doubt, be attributed to random sampling. 



COMPARISON OF SAMPLES OF HERRING TAKEN IN 1924 AT DIFFERENT LOCALITIES 



IN SAGINAW BAY 



Since the 1924 samples of herring taken at one locality in Saginaw Bay are com- 

 parable, they may be treated as a unit collection. Are the samples taken in different 

 parts of Saginaw Bay also comparable? Or is the Saginaw Bay herring population 

 composed of various races, each of which remains segregated and spawns on its own 

 particular breeding grounds in the bay? To obtain some light on this subject Tables 

 53 and 54 were constructed. In these the data of the herring of a given locahty in 

 the bay, shown in the two preceding tables, are combined, Table 53 summarizing the 

 data of Table 51 and Table 54 those of Table 52 on computed lengths. 



