DOI: https://doi.org/10.36347/sajb.2025.v13i01.011

Pages: 92-103

The study aims to assess changes in biological parameters, mainly those related to the diet of the predator Lates niloticus (Linaeus, 1762) on the N'Zo River, which is strongly impacted by climatic variations. Sampling took place from July to October (rainy season) and March to April (dry season) 2023 at landing sites in the departments of Guiglo (Cavally region) and Duekoué (Guémon region) in Côte d'Ivoire. A total of 121 individuals (including 46 females and 75 males) with standard lengths ranging from 10.5 to 57 cm were analyzed. Analysis of stomach contents revealed that the relative food importance index (RIa) of Lates niloticus was composed of two prey categories: fish (73,68%) and insects (12.23%). No cannibalism was recorded. The food spectrum, restricted to 5 prey families (Cichlidae, Cyprinidae, Bagridae, Characydae and Gryllidae), was the same whatever the season. Oreochromis niloticus (Cichlidae) was the most consumed species (47.24%), regardless of season or sex. An analysis of variance showed that RIa was not significantly different between seasons (F= 3.23.10 -6; P= 0.999) and also between sexes (F= 1.776.10-8; P= 0.999). However, multinomial logistic regression analysis relating sex, season and stomach contents of Lates niloticus showed that crickets were significantly present in the diet of the piscivorous Lates niloticus (P = 0.0010339). The insects, Gryllidae, were indeed the most consumed (32.03) in individuals considered immature (<19cm). Lates niloticus therefore had a special entomophagous diet during the juvenile (immature) and young adult (19-33 cm) stages, followed by a strictly piscivorous diet in adulthood. There was a positive correlation between intestine length and standard fish length (R2= 0.64; a = 0.76). However, the intestinal coefficient (IC), which was 0.70 ± 0.20, shows that the diet of Lates niloticus is highly specialized. It was a fish-eater with omnivorous tendencies.