SOME IMPORTANT BAIT FISHES 



COVER OVER 





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25 — 



Figure 41. — Typical raceway construction for spawning creek chubs. Upper : Dia- 

 grammatic view of streambed and shelters. Lower : Cross section of spawning 

 area. (Diagrams courtesy of the Michigan Department of Conservation.) 



against the continuous current — 

 resulting in the formation of areas 

 of slow and fast-moving water and 

 thus simula.ting conditions i n 

 spawning areas in natural waters; 

 and (2) to prevent the refuge pools 

 from being filled by washing gravel. 

 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 projecting too 

 high above the streambed (forming 

 barriers) were lowered; others, too 

 low to be effective in checking the 

 current and preventing wash, were 



raised to the desired height. The 

 outlet valve was then closed and the 

 water allowed to accumulate within 

 the basin of the pond until it 

 reached a level even with the lower 

 end of the stream (fig. 41, lower). 



After the sluice boards had been 

 installed in the outlet to maintain 

 this height, the outlet valve was 

 opened and the overflow water al- 

 lowed to pass through. Finally, 

 the refuge zones were covered with 

 lids made of tarred paper and strips 

 of lath and netting was stretched 

 over the stream. 



Anyone contemplating the propa- 

 gation of creek chubs need not con- 

 struct a raceway exactly duplicating 



88 



