106 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Table 20. — Comparison of growth of lake herring, of same age and length at capture, taken in pound nets at the same time 



of year at different locations 



[Calculated total length In inches] 



Length group and locality 



Number 

 offish 



Length at 

 capture 



Length at end of year of life- 



Length Increment 



Feb. 22-27, 1950; 



Age group IV; 10.&-10.4 in.: 



Escanaba (north) . _ _ 



Schumachers Point (souths 

 Age group IV; 10.5-10.9 in.: 



Escanaba (north) 



Schumachers Point (south). 

 Age group IV; 11.0-11.4 In.: 



Escanaba (north) 



Schumachers Point (south). 

 Nov. 29-Dec. 4, 1950: 



Age group III; 10.0-10.4 In.: 



Fox (north) 



Sister Bay (south) 



Age group III; 10.5-10.9 in.: 



Fox (north) 



Sister Bay (south) 



Age group III; 11.0-11.4 In.: 



Fox (north)-- --. 



Sister Bay (south) 



Feb. 20-22, 1951; 



Age group IV; 10.0-10.4 In.: 



Ingallston (north) 



Schumachers Point (south). 

 Age group IV; 10.5-10.9 in.: 



Ingallston (north) 



Schumachers Point (south). 

 Age group IV; 11.0-11.4 in.: 



Ingallston (north) 



Schumachers Point (south). 

 Jan. 21-22, 1952: 



Age group IV; 10.5-10.9 in.: 



Escanaba (north) 



Pensaukee (south) 



Age group IV; 11.0-11.4 in.: 



Escanaba (north) 



Pensaulcee (soutli) 



Age group IV; 11.5-11.9 In.; 



Escanaba (north) 



Pensaukee (soutli) 



37 

 106 



10.2 

 10.3 



10.7 

 10.7 



11.3 

 11.2 



10.3 

 10.3 



10.7 

 10.7 



11.1 

 11.1 



10.3 

 10.2 



10.7 

 10.7 



11.1 

 11.1 



10.7 

 10.8 



11.2 

 11.1 



11.7 

 11.6 



5.0 

 5.2 



5.0 

 5.5 



5.1 

 5.6 



6.1 



4.9 



5.4 

 5.5 



5.2 

 5.6 



5.1 

 5.2 



5.1 



5.4 



5.4 

 5.4 



4.8 

 5.3 



5.1 



6.6 



5.2 

 6.8 



7.3 

 7.6 



7.6 

 8.0 



7.9 

 8.3 



7.5 

 7.3 



7.9 

 7.9 



7.9 

 8.1 



7.4 

 7.5 



7.7 

 7.8 



8.0 

 8.0 



7.6 

 7.7 



7.8 

 8.2 



8.3 



8.4 



9.0 

 9.2 



9.4 



9.9 

 10.0 



9.3 

 9.3 



9.7 



9.0 

 9.0 



9.4 

 9.5 



9.8 

 9.8 



9.4 

 9.6 



9.8 



10.2 

 10.3 



10.2 

 10.3 



10.7 

 10.7 



11.3 

 11.2 



10.3 

 10.2 



10.7 

 10.7 



11.1 

 11.1 



10.7 

 10.8 



11.2 

 11.1 



11.7 

 11.6 



5.0 

 5.2 



6.0 

 6.5 



6.1 

 6.6 



5.1 

 4.9 



5.4 

 6.6 



6.2 

 5.6 



5.1 

 6.2 



5.1 

 5.4 



5.4 

 5.4 



4.8 

 6.3 



5.1 

 5.6 



5.2 

 5.8 



2.3 

 2.4 



2.6 

 2.5 



2.8 

 2.7 



2.4 



2.4 



2.5 

 2.4 



2.7 

 2.6 



2.3 

 2.3 



2.6 

 2.4 



2.6 

 2.6 



2.7 

 2.4 



2.7 

 2.6 



2.1 

 2.6 



1.7 

 1.6 



1.2 

 1.1 



1.3 

 1.1 



1.4 

 1.2 



1.9 

 1.9 



1.3 

 1.2 



1.3 

 1.2 



1.3 

 1.3 



1.3 

 1.2 



1.4 



1.2 



1.5 

 1.3 



tions (table 21) are so arranged that in each 

 section of the table the vertical columns show the 

 calculated growth in different years of life but in 

 the same calendar year, the horizontal rows give 

 a comparison of the growth in different calendar 

 years for the same year of life, and each diagonal 

 row gives the growth history of a single year class. 

 For the quantitative determination of annual 

 fluctuations of growth the data were subjected to 

 the analysis described by Hile (1941), a procedure 

 involving the determination of the percentage 

 change in growth from each year to the next. The 

 chain of estimates thus obtained was then ad- 

 justed to a mean of 0.0 for the period of years cov- 

 ered by the data (table 22). The fluctuations 

 show a trend toward an improvement of growth 

 during the period covered and show a possible 

 tendency to be cyclic. From a value slightly 

 below average in 1944 ( — 2.1 percent), growth 

 declined to a minimum of —6.5 in 1946 (fig. 5). 

 The year 1947 was the first in a 4-year period of 

 improvement that culminated in growth 9.1 per- 

 cent above average in 1950. 



Figure 5. — Fluctuation of growth in length of lake herring 

 from the 1944-51 mean. 



Temperature is commonly considered an im- 

 portant factor in the determination of fluctuations 

 in growth. Hile (1936, pp. 276-280) discussed 

 the possible influence of air temperature on the 

 growth ofcisco populations in northeastern Wis- 

 consin lakes and cited works of several authors 

 who found a positive correlation between summer 

 temperatures and the amount of growth of sev- 

 eral European species of coregonids. Concerning 

 the Wisconsin cisco populations Hile concluded — 



The failure of variations in the amount of growth in 

 different calendar years to show any close general depend- 



