AGE AND GROWTH OF THE CISCO 
277 
lake might be expected to vary somewhat with annual fluctuations in the abundance 
of the population wit tun that particular lake. References to the literature on the 
question of the change in growth rate that accompanies change in the density of 
population have been made previously (pp. 254-257). Some mention should be made 
of the much less numerous observations on the relationship between annual fluctua- 
tions in average temperature and annual fluctuations in growth, particularly as these 
observations have been made with reference to coregonids. 26 
Huitfedlt-Kaas (1917) demonstrated a close correlation between first-year 
growth and average annual temperature in the lagesild or pollan ( Coregonus albula ) 
of Mjpsen and Storsjp. At the same time he recognized the possible effect on growth 
rate of changes in the density of population from one year to another. 
In a later paper (Huitfedlt-Kaas, 1927) he was able to show a relationship between 
the amount of growth and summer temperature in the gwiniad ( Coregonus lavaretus) 
and the pollan ( C . albula). (He noted a similar situation in several tribes of the 
trout ( Salnio eriox).) 
Olofsson (1932) compared the growth of three species of Coregonus (C. wartmanni 
borealis, C. wartmanni generosus, and C. lavaretus) of Norrland in the warm summer of 
1930 with that in the cold summer of 1931. In all three forms there was large growth 
in the warm summer and slow growth in the cold. Olofsson called attention particu- 
larly to the fact that occasionally growth during a cold season may be so small that the 
year ring formed on the scales might easily be overlooked. Some scales may even 
fail to form a distinct year band. The differences observed between growth of the 
years 1930 and 1931 were exhibited by fish of different sizes and ages. 
Krogius (1933) found that the curve of the deviation from average growth in 
different calendar years for Coregonus lavaretus of Lake Baikal followed closely the 
corresponding curves for deviation from average annual temperature and average 
annual precipitation. 
Van Oosten (1929) found no relation between annual fluctuations in the air 
temperatures during the growing season and the annual fluctuations in the first 
year’s growth in the Saginaw Bay herring (L. artedi). 
There are no records of water temperature available upon which to base a com- 
parison of annual deviation from normal temperature during the growing season and 
annual deviation from average growth in the cisco populations of this study. It is 
possible, however, to make a comparison between annual deviation from average 
growth and annual deviation from normal air temperature 27 in the region. For this 
purpose the records of the meteorological stations at Big St. Germaine Dam and Rest 
Lake Dam were taken as representative for Trout, Muskellunge, and Silver Lakes, 
while the records of the Minocqua station were taken as representative for Clear 
Lake. 28 
Since the lengths of the growing seasons (pp. 249-253) are not the same in the 
different lakes the annual deviations from normal summer temperature were calculated 
18 Although his work does not deal with the coregonids, mention should be made of Segerstrale’s (1932, 1933) observations on 
the relationship between summer temperature and the growth of fishes in southern Finland. This work dealt with the perch 
( Perea fluviatilis) and several species of cyprinids. Segerstrale found that the amount of growth during the summer is a quantity 
highly sensitive to the average summer temperature. 
27 Climatological Data for the United States, U. S. Department of Agriculture, Weather Bureau, vols. X-XVIII, 1923-31. 
28 Muskellunge Lake lies about 3 kilometers east of Trout Lake, and Silver Lake lies about 1 kilometer off the southwest corner 
of Trout Lake. The St. Germaine weather station is about 13 kilometers southeast of Trout Lake while the Rest Lake station lies 
at an approximately equal distance to the northwest of Trout Lake. The town of Minocqua is about 6 kilometers due west of Clear 
Lake. 
