Size at Maturity and Fecundity of Oreochromis niloticus and Mouth Brooding Tilapiines Indigenous to Kafue Flood Plain Fishery, Zambia.

The present investigation was conducted to ascertain whether or not Size at maturity, Fecundity, and Total Length-Fecundity variation could explain the population dominance of Oreochromis niloticus (Linnaeus 1758) over three spot breams Oreochromis andersonii (Castelnau 1861) and Green-Headed Bream Oreochromis macrochir (Boulenger 1912) in the Kafue Flood Plain during the spawning season (October 2020 to March 2021). Fish samples caught using a full standard multifilament net with mesh sizes ranging from 25 to 150 mm increments of 12.5 mm were purchased from Local Fishermen at Chanyanya and Kasaka fishing camps. The Total length of each fish was recorded to the nearest 0.1 cm using the fish measuring board. Reproductive stages of the three Tilapiine fish species were determined using standard keys. Whole ovaries from sexually mature females (ripe) were weighed and preserved in 10% formalin solution; logistic regression lines were used to determine size at maturity (L50). Fecundity was determined using gravimetric procedures. The O. andersonii matured at a Total length of 210.98 mm, O. macrochir at 199.48 mm, while O. niloticus matured at 189.82 mm. The O andersonii had mean Fecundity of 1843.92 ± 68.805; O. macrochir had 1640.82 ± 92.164 while O. niloticus had 1422.24 ± 91.103. The relationship between Fecundity and Total length was found to be strongest in O. macrochir (y=12.845x-1175; r=0.8770), followed by O. niloticus (y = 12.912x – 1614.3; r=0.8104) and finally O. andersonii (y=10.715x-591.91; r=0.7606). The studied characteristics among the Tilapiines indicated that O. niloticus was superior in reproductive biology. There should be proper guidelines in the laws and regulations regarding the introduction of O. niloticus into other water bodies. The O. niloticus must be promoted in aquaculture because of its reproductive advantages compared to the local Tilapiines.