the water level of some of the pools, caused by 

 manipulation of the river flow. It can be as- 

 sumed that some of the effects of these suddenly 

 dropped water levels had to do with the catch - 

 ability of the fish. However, no quantitative 

 relationships can be demonstrated with the data 

 at hand. Some of the level manipulations had 

 been completed before the fishing season got 

 well under way, and others took place at various 

 times and in various amounts and places. It is 

 difficult to discern any effects upon the all-over 

 average fishing success (figures 3 and 4) . 



Weather, moon phases, etc . At various times 

 and by various persons, scientific or otherwise, 

 many heated assertions have been made that 

 fishing success depends upon the weather in 

 general, the air temperature, the wind direction 

 and velocity, the barometric pressure, the 

 degree of cloudiness, the phase of the moon, 

 something with a high-sounding title like "solunar 

 cycles", or any one of a dozen other factors. 



Eschmeyer (1937) found that the fishing 

 was best when the particular combination of 

 mild air temperature, clear sky, and light wind 

 existed; but he was not able to tell which of 

 these factors was the most important. For an- 

 other season he reported (Eschmeyer, 1935) 

 that he was not able to find a close relationship 

 of the fishing with any of several meteorological 

 factors. 



Needless to say, in a study such as the 

 present one, the influence, if such there exists, 

 of any one or more of these various factors 

 mentioned above could be assessed with extreme 

 difficulty if at all. The first and foremost poser 

 is the fact that the fishing success for any given 

 day or week varied greatly from place to place 

 within the general area . It is conceivable that 

 some factors such as wind, air temperature, and 

 cloudiness could also vary from place to place 

 at any given time . It is further conceivable, 

 therefore, that there could be a definite covari- 

 ance between some of these factors and the catch 

 of fish; but with the information available, it is 

 almost hopeless to try to demonstrate any such 

 relationship . 



On the other hand, any such factor as the 

 phase of the moon or the interactions of moon, 



sun, and tides, would be identical for all of the 

 localities within this area at any given time. 

 (To some extent this would be true also for the 

 barometric pressure, since most of the storms 

 in this region are generalized.) Therefore, any 

 effect upon the fishing exerted by these factors 

 should be uniform throughout the area. Obvious- 

 ly, it is difficult to ascribe poor fishing in one 

 locality and concurrent good fishing in another 

 to the same cause. 



A set of fishing forecasts (for the sum- 

 mer of 1945) was chosen, one which appeared on 

 a calendar in the form of shaded figures ("the 

 blacker the fish, the better the day for fishing") . 

 Although this forecasting system is only semi- 

 quantitative in nature, a bit of mathematical 

 maneuvering made it possible to obtain a crude 

 statistical relationship between the forecasted 

 fishing success and the actual recorded catch 

 per hour (total averages, all pools),, day by day 

 throughout the summer. The correlation co- 

 efficient turned out to have a (very weakly 

 significant) negative value. In other words, this 

 particular forecast was wrong more often than 

 it was right. 



Elser (1953) obtained no significant cor- 

 relation between catch and the data of "solunar" 

 tables. 



Depth of snow. There is some reason to believe 

 that the depth of snow on the ice may exert con- 

 siderable influence upon the amount of winter 

 feeding by the fish and hence upon the fishing 

 success. Heavy snow cover cuts down the amount 

 of light entering the water, and presumably 

 makes it more difficult for fish to find food (or 

 bait) . 



The desirability of having data on the 

 amount of snow cover occurred to the writer be - 

 latedly; no field measurements of snow depth were 

 made during the creel census operations. There- 

 fore, for any sort of computations regarding the 

 relationship of snow depth to fishing success, 

 reference could be made only to weather station 

 records of "snow on the ground" . These figures 

 for the La Crosse Weather Station for the winter 

 1944-45, are shown in the graph of figure 3. In 

 a very general way the changes in depth of snow 

 on the ground at the La Crosse station corres- 



41 



