49 



The next important step in the culture of creek 

 chubs is the stocking of the raceway with breeders. 

 Recommended stocking rates calculated on a theoretical 

 basis derived from observations and studies conducted 

 in Michigan mayormay not be entirely satisfactory for 

 all types of raceways. It is believed, however, that 

 a brood stock should contain more females than males 

 (approaching a ratio of 2 to 1 or 3 to 2). Furthermore, 

 each female in stock composed of 3.5- to 7-inch fish 

 should be provided with 1.5 square feet of spawning 

 area for egg deposition, and for each female from a 

 group composed of 4- to 8-inch chubs 2 square feet of 

 area are needed. In calculating the square feet of 

 available spawning area in a raceway, the margins along 

 the banks (about 3 inches on each side of the stream) 

 and any areas used for refuge zones or current deflect- 

 ing structures should be omitted. Generally, about one- 

 fourth of the total area will be consumed by these 

 structures. To illustrate the use of these recommenda- 

 tions, let us suppose that an operator had a raceway 

 200 feet long by 4 feet wide and wished to determine 

 the number of breeders necessary forstocking. Assuming 

 that one-fourth of the total area would be consumed by 

 the banks, refuge zones, and other structures, he would 

 have to make his calculations upon the remaining 600 

 square feet of stream bed. If 3- to 7-inch females were 

 used, about 400, of these would be required, and 200 

 males would be required if a sex ratio of 2 to 1 were 

 established or about 266 males if a 3 to 2 ratio were 

 followed. If 4- to 8-inch females were used, 300 would 

 be needed and the corresponding ratio of males would 

 be included. The mortality rate of adult creek chubs 

 during the spawning season has been exceptionally high, 

 sometimes amounting to as much as 75 percent. To be 

 assured that an adequate supply of adult fish will be 

 available each spring, provision should bemade whereby 

 a new group of fish will be maturing each year. 



Creek chub breeders should be introduced into the 

 raceway at a time when this species is known to be 

 spawning in nearby natural waters. If a check cannot 

 be kept on the natural spawning or if no natural spawn- 

 ing occurs in the area, it is advisable to introduce 

 the fish when the water temperature in the raceway has 

 reached 55° F. for a 2- or 3-day period. Creek chubs 

 usually start to spawn during the latter part of April 

 in waters north of an imaginary line drawn east and west 

 from the Michigan-Ohio border. Spawning is terminated 

 late in May or early in June in the Lake Superior area 



