Reproductive performance, growth, and survival of selected and wild X selected channel catfish.

Wild (W) and selected (S) strains of channel catfish (Ictalurus punctatus) were crossed to attempt to introduce genes from wild stocks into a domesticated stock without loss of growth or survival performance. W strain broodfish were from the Kaskaskia River in Illinois and had no history of artificial selection. The S strain broodfish had undergone two generations of selection for multiple-traits since 1974 and had become adjusted to tank, cage, and pond culture conditions. Females and males from both strains were paired in individual spawning pens in all possible combinations and the 19 subsequent egg masses were artificially incubated. The 15 S♀XS♂, 6 W♀XS♂ and 9S♀xW♂ crosses produced 10, 3 and 6 egg masses, respectively. None of the 7 W♀XW♂ pairs spawned. The fish density was standardized to two tanks of 500 in each full-sib family at 4 weeks of age and 200 in each at 12 weeks of age. Domesticated and crossbred fish did not differ in spawn characteristics or 4-week body weight but domesticated catfish grew progressively faster than crossbreds and were 55% heavier and 16% longer by 40 weeks of age. No survival differences were observed among the three genetic groups. A 9-week cage test which followed the tank culture also indicated that domesticated fish were superior to crossbreds in body weight, total length, condition factor, and carcass weight. These results indicated that a single WxS cross did not establish improved gene combinations without loss of growth performance.