198 U. S. BUEEAU OF FISHEEIES 



The fingerling production amounted to 467 per acre. It is quite clear 

 from these results that heavy stocking with brood fish is uneconomi- 

 cal. It not onl}^ means an additional expense for carrying a larger 

 number of brood fish, but also results in a far smaller production of 

 fingerlings. 



WHITE CRAPPIE 



The experiments referred to in the last paragraph fail to distin- 

 guish between the two species of crappie ; and, therefore, there is no 

 means of determining whether each species is equally adaptable to 

 pond culture. The experiments outlined in the following para- 

 graphs show that both sj)ecies have been reared in ponds with a fair 

 degree of success. 



In 1*927. the white crappie {Pom^oxis annuJaHios) was reared 

 together with bluegill sunfish in I) 1. The pond was stocked at the 

 rate of 80 adult crappie and 233 bluegill per acre. The fingerling 

 production was at the rate of 8,973 crappie and 44,899 bluegill per 

 acre. Since the bluegill production runs much higher than this 

 when they are reared by themselves, it appears that the crappie fed 

 on the young bluegill and thus held them in check. As far as the 

 bluegill production is concerned, this means fewer but larger finger- 

 lings. In 1928 another attempt was made to rear white crappie, 

 this time using golden shiner as a forage fish. Pond D 9 was used 

 for this experiment, and was stocked at the rate of 44 crappie and 

 400 golden shiners per acre. When the pond was drained in Octo- 

 ber, it yielded 6,795 fingerling crappie (8,720 per acre) and 13,788 

 fingerling shiners (20,130 per acre). The relatively large number 

 of shiners that survived suggests that this minnow is not a suitable 

 forage fish for the white crappie. We have some evidence indicat- 

 ing that the blackhead minnow would be more suitable. 



BLACK CRAPPIE 



That the black crappie {P. sparo?des) or calico bass can be pi'opa- 

 gated successfully in ponds is indicated by the results obtained in 

 1928. In the spring of that year D 2 was stocked with 14 adult 

 black crappie (46 per acre), 30 adult bluegill (99 per acre), and 

 20 adult bullheads (66 per acre). This pond produced 3,726 finger- 

 ling crappie (12,295 per acre), 2,177 fingerling bluegill (7,184 per 

 acre), and 3,505 fingerling bullheads (11,016 per acre). The crappie 

 production compared favorably with that for 1925, when the two 

 species were raised together. 



Our great difficulty in propagating crappie is that the sexes can 

 not readily be distinguished. In the case of the bass, immediately 

 before the spawning season, one can tell with a fair degree of 

 accuracy whether a given individual is a male or a female, but with 

 ''rappie this is not possible. Another difficulty lies in the fact that 

 the crappie is very sensitive to handling. This results in heavy losses 

 of brood fish during the summer and necessitates a new stock practi- 

 cally everj' year. These difficulties, we believe, explain some of the 

 poor results that have been obtained with these species in pond 

 cultural work. 



