COMMON FISHES OF MISSISSIPPI RIVER 
189 
spawning evidently concluded in the second half of May. The only ripe example of 
the “mongrel” buffalo fish noted that year was taken on May 17. On June 1, 1915, 
in a little creek then having perhaps 7 feet of water but which had been less than 
knee-deep a couple of months earlier, 17 buffalo fish were taken and identified in the 
field as urus and hubalus. All were big fish, the largest measuring 32 inches (81 
centimeters) in length. Several examples, believed to include both species, were 
pressed and found to be “ripe.” The presence of the fish in spawning condition 
in a small creek suggests that they sometimes ascend small streams to spawn. 
Figure 21— Quantities of buffalo fisbes taken near Keokuk, Iowa, by weeks, May 27 to September 
9, 1916 
Some indication of the relative abundance of buffalo fishes at different seasons 
at Keokuk may be had from Figure 21, based upon reports from the local markets 
received by Stringham each week during the period covered. 
Considerable fluctuation in weekly catches appear, as would be expected; but 
in a general way the weekly catch oscillated around 3,750 pounds as a mean from about 
the end of the breeding season (when the record began) until the end of July. The 
drop about the latter date seemed in no way related to the stage of the river, which 
had been declining since the middle of June and continued to do so; and it was thought 
not to be explainable by any change in intensity of fishery, for no change was observ- 
able. It may have been related to changing water temperature, which was at its 
maximum just then and which declined gradually but irregularly. Possibly it was 
referable to the flights of May flies, the large ones of which ended at this time, although 
smaller flights occurred later. (See Needham, 1920, p. 272.) There is, of course, the 
