Table 4. The effect of female Sumtherodon niloticus stocking density on the production of all-male hybrid fingerlings (S. niloticus x S homorum) in 35*m2 ponds in
Brazil over periods ranging from 71 to 111 days (after Lovshin 1980).
Number of female S. niloticus in the spawning pond, i.e.,/350 m^2
No. of replicates 5 9 6 27 61
No. of male S. hornorum/pond 3 5 10 5-50 10
Averwe no. of fingerlings producedlpond 2.117 2,350 1,643 1,475 2,763
Range of the average no. of fingerlings produced 580 to 3.619 93 to 3,639 821 to 2.439 0 to 7.149 0 to 8.443
Average no. of fingerlings per female 353 235 110 59 55
Estimated no. of females spawningalpond 5 6 4 4 7
Estimated % of females spawning 83 60 27 16 14
a~ssuming 400 eggs per spawn, 100% survival of eggs to fingerlings. and females spawned only once in each spawning period.