392 



BULLETIN OF THE BUREAU OP FISHERIES 



Table 59. — Total length attained at end of each year of life by lake herring taken at various ports on 

 Lake Huron. Each average is based on uncorrected computed lengths of several year classes ' 



"^ 



' Number upon which average is based is given in parentheses; the last value of each horizontal row shows the actual length 

 when captured. 



An examination of Tables 58 and 59 and of Figure 43 shows that the most rapidly 

 gi'owing herring are those of Bay City and East Tawas. The Oscoda herring grew 

 nearly as rapidly as the Bay City and East Tawas fish. The former rank second 

 in size at corresponding ages to the latter. The herring of Alpena, St. Ignace, and 

 Killarney grew at about the same rate throughout life. They rank third in size at 

 corresponding ages to those of Bay City and East Tawas. The Wiarton herring taken 

 in Georgian Bay rank fourth in rate of growth. 



The different growth rates of the herring of these localities may possibly be 

 correlated with the different conditions of life. Bay City and East Tawas are situated 

 on Saginaw Bay, a large body of shallow water 20 miles wide and 50 miles long, more 

 than half of which is less than 5 fathoms (30 feet) deep. The bay undoubtedly 

 provides excellent na,tural conditions for the growth of young fish. Oscoda is situated 

 about 15 miles north of East Tawas just outside of Saginaw Bay. The herring of 

 Alpena, situated on Thunder Bay, presumably are confined in early life to a much 

 smaller area of shallow water than those of Saginaw Bay and are more exposed to 

 the colder waters of the lake proper. In fact, many of the Alpena herring spawn and 

 live in the unprotected waters of Lake Huron. St. Ignace, on the Straits of Mack- 

 inac, and Killarney, on the North Channel, are situated in the most northern part 

 of Lake Huron. Herring of these localities probably are subjected to colder waters 

 than are those of Saginaw Bay; the growing season of the former may also be shorter. 

 The Wiarton herring presumably are most restricted in their range. As may be seen 

 from the map (fig. 1), the 20-fathom contour line, beyond which herring seldom 

 occur near the bottom, lies very near the shore hue along the entire west coast of 

 Georgian Bay from Owen Sound north to Tobermory Light. A study, then, of the 

 general hydrographic features of each of the above localities alone would lead us 

 to expect that Saginaw Bay would produce the fastest growing herring and Wiarton 

 the slowest growing. 



This incomplete comparative study shows at least two things: (1) That there 

 may be distinct races of herring in Lake Huron or, at any rate, that there are distinct 

 differences between the growth rates of the herring of certain localities in Lake 



