REPRODUCTIVE BIOLOGY AND FEEDINDG HABITS OF THE NILE TILAPIA OREOCHROMIS NILOTICUS (L. 1758) (PISCES: CICHLIDAE) IN DAMTE DAM, WOLAITA ZONE SOUTHERN ETHIOPIA

Abstract

Reproduction, feeding and condition factor of O. niloticus were investigated in Damte Dam based on the samples collected from February, 2024 to September, 2024. A total of 584 fish samples were caught ranging from 10 cm to 33.9 cm TL and 32 g to 750 g TW for males and 9.7 cm to 33.9 cm TL and 32.1 g to 421 g TW for females. The aim of this study was to investigate reproduction and feeding habits of O. niloticus in Damte Dam, Ethiopia. The overall male to female sex ratio was significantly different from 1:1 (ꭓ2=4.281, p<0.05). Lm50 for males and females were 14.7 cm TL and 13.9 TL cm, respectively. GSI values ranged from 0.26 to 1.59 for males and 0.25 to 1.8 for females. The fish bred throughout the sampling period with intensive breeding months in May, June and July. The length weight relationship was found to be curvilinear (TW = 0.0105TL3.1988). ACF value of male was minimum values of 0.40 to maximum value of 2.99 with a mean of 0.933 ± 0.013 and females O. niloticus ACF was ranged from 0.75 to 2.77 with mean value of 1.39 ± 0.016. Detritus (94.61%, 34.53%), macrophytes (88.41%, 29.59%), phytoplankton (85.18%, 31.36%), insects (18.33%, 2.61%) and zooplankton (11.59%, 1.90%) were using frequency of occurrence and volumetric analyses respectively. In general, ACF and ripe gonad were inversely proportional, and compared to other studies. The fecundity of O. niloticus in Damte Dam was relatively low. There was no observable variation in the food items between dry and wet months, but notable ontogenetic variation was seen in the diet. O. niloticus under 15 cm TL should be protected to save the breeding fish from the risky fishing of locals. The study emphasizes the importance of raising public awareness about the value of using fisheries resources to improve local communities' living standards and research on Damte Dam conservation