Breeding pattern of Oreochromis niloticus (Linnaeus, 1758) versus native congeneric species, Oreochromis macrochir (Boulinger, 1912), in the upper Kabompo River, northwest of Zambia

• Published in: Ecology and evolution 2021-12, Vol.11 (23), p.17447-17457
• Main Authors: Jere, Arthertone, Jere, Wilson W. L., Mtethiwa, Austin, Kassam, Daud
• Format: Article
• Language: English
• Subjects: Aquaculture; Biodiversity; Biology; Breeding; Contingency; Contingency plans; Ecosystem biology; Ecosystems; exotic fishes; Fish; Fisheries; Fisheries management; Fisheries research; Hypotheses; Indigenous species; invasive patterns; Invasive species; Kabompo River; Native species; Oreochromis macrochir; Oreochromis niloticus; outbreeding; Reproduction; River ecology; Rivers; Sex; Sex ratio; Spawning; spawning events; Tilapia; Wildlife; Zambia
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.8377

Investigating the determinants of the reproductive biology of fishes is an essential component of fisheries research. Tilapia breeding patterns were investigated to determine the impact of non‐native Oreochromis niloticus on the native congeneric Oreochromis macrochir in the upper Kabompo River in the Northwest of Zambia using the gonadosomatic index and the sex ratios. Oreochromis niloticus was the most abundant fish caught (221, 63.5%) than O. macrochir (127, 36.5%). Results showed that the overall gonadosomatic index means of O. macrochir in both sections were similar. Oreochromis macrochir bred in December and February–March, with no reproduction in June. However, O. niloticus in the invaded section indicated all year reproduction through reduced spawning in May–June, with increased spawning activity in February–March. The sex ratio (females: males) was 1:1.3 and 1:1.7 for O. niloticus and O. macrochir, respectively, and both significantly deviated from the sex ratio of 1:1 (ꭓ2 = 8.42 and 9.37, p