47 



screened stones in equal proportions). About 38 cubic 

 yards of gravel were used to surface the 300-foot 

 raceway. Immediately after the spreading of the gravel, 

 splash boards (lower drawing, fig. 12) were installed 

 across the channel at each refuge zone. These struc- 

 tures (boards) were driven into the bottom soil to a 

 depth of 1.5 feet and were exposed about 3 inches above 

 the gravel. The purpose of these devices wws twofold: 

 one, to act as- a break against the continuous current — 

 resulting in the formation of areas of slow and fast 

 moving waters and thus simulating conditions used by 

 chubs as spawning areas in natural waters; and two, to 

 prevent the refuge pools from being filled by washing 

 gravel. In order to determine to what degree these 

 splash boards were accomplishing their purpose, the 

 inlet valve of the pond was opened to allow 1.5 cubic 

 feet of water per second to flow down the stream channel 

 as a test. Some splash boards proj ecting too high above 

 the stream bed (forming interfering barriers) were 

 lowered; others, too low to be effective in checking the 

 current and preventing wash, were raised to the desired 

 height. Following these alterations, the outlet valve 

 was closed and the water allowed to accumulate within 

 th.e basin of the pond until it reached a level eveiji 

 with the lower end of the stream (fig. 12). At this 

 point, after sluice boards had been installed in the 

 outlet to maintain this height, the outlet valve was 

 opened and the overflow water allowed to pass through. 

 As the last task in preparing the pond for brood fish, 

 the refuge zones were covered with lids made of tarred 

 paper and strips of lath, and netting (fig. 12) was 



stretched over the stream. 



Anyone contemplating the propagation of creek chubs 



need not construct a raceway exactly duplicating either 

 of the two just described. It is important to take into 

 account when constructing a spawning stream the ecologi- 

 cal conditions affecting the breeding habits of the 

 creek chub, such as currents, pools, hiding places, and 

 types of bottom soil. As life-history studies show 

 that the creek chub prefers certain types of habitat, 

 it is desirable to provide these conditions as com- 

 pletely as possible. Raceway streams can be made any 

 length desired; the width does not necessarily have to 

 be confined to 4 or 5 feet, provided that a sufficient 

 volume of water is available to operate effectively a 

 wider channel. The most important thing to consider 

 is the water supply. The water should be clear in 

 color, have a temperature range of 55° to 60° F. during 



