CREEK CHUB 



either of the two just described. 

 When constructing a spawning 

 stream, it is important to take into 

 account the ecological 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 a certain 

 type of habitat (p. 86), it is desir- 

 able to provide these conditions as 

 completely as possible. Raceway 

 streams can be made any length de- 

 sired ; 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 effec- 

 tively a wider channel. Most im- 

 portant is the water supply. The 

 water should be clear in color, have 

 a temperature range of 55° to 60° 

 F. during the spawning season, and 

 be free of other species of fish. 



Stocking the raceway 



Selecting the brood stock. — An 

 operator selecting brood stock must 

 bear in mind that the male chub 

 grows larger than the female; that 

 the mature male is distinguishable 

 from the female by the presence of 

 bony protuberances (horns) on the 

 head immediately before and dur- 

 ing the spawning season; and that 

 the male is usually highly colored 

 during the spring, having tinges 

 of red on the paired fins and abdo- 

 men. In contrast, the adult female 

 is generally smaller and more drab 

 in color and has a swollen abdomen 

 during the spawning season. 



Results of Michigan studies in 

 the selection of brood stock indi- 



cate that it is advisable to use 6- 

 to 8-inch males and 5- to 6-inch 

 females for breeders. If larger 

 males (7 to 10 inches in length) are 

 available and the total stock of 

 breeding males could be represented 

 by fish of this size, results should 

 prove satisfactory. Likewise, if 

 larger females (6 to 8 inches in 

 length) are available, they could 

 also be used. 



It is not advisable to mix small 

 (5-inch) mature males with larger 

 (10-inch) males in the same race- 

 way, because mortality occurs as a 

 result of fighting. Where small (3- 

 inch) females are mixed with larger 

 (8-inch) females in the same race- 

 way, a prolonged spawning season 

 occurs, resulting in a loss of fry. 

 The larger females mature about 2 

 weeks earlier than the smaller ones, 

 and by the time the smaller females 

 are through spawning, many fry 

 have hatched and emerged from the 

 earlier-formed nests. The presence 

 of fry in the raceway and base pond 

 before the brood stock is removed 

 naturally complicates removal of 

 the fry. 



One more suggestion concerns the 

 age of adult fish. Normally, only 

 a few pond-reared creek chubs can 

 be expected to mature in their first 

 year and be used as breeders. In 

 the second year, possibly 50 percent 

 will mature (depending on the rate 

 of growth, the larger fish being the 

 more favored) ; as a result, most of 

 the brood stock will have to be se- 

 lected from older fish. In natural 

 waters, female creek chubs nor- 

 mally do not mature until their 



89 



