World Aquaculture Safari 2025

June 24 - 27, 2025

Kampala, Uganda

AGE DETERMINATION AND GROWTH OF NILE TILAPIA Oreochromis niloticus IN LAKE HAYQ, ETHIOPIA

Alemken Berihun1, Minwyelet Mingist2, Abebe Getahun3 and Degsera Aemro2 and Dagnew Mequanent4

1Department of Wildlife and Ecotourism Management, College of Agriculture and Natural Resources, Gambella University, P. O. Box 126, Gambella, Ethiopia

2Department of Fisheries and Aquatic Sciences, College of Agriculture and Environmental Sciences, Bahir Dar University, P. O. Box 79, Bahir Dar, Ethiopia

3 Department of Zoological Sciences, College of Natural and Computational Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia

4Department of Biology, College of Natural and Computational Sciences,   University of Gondar, P.O. Box 196, Gondar, Ethiopia

*Corresponding author: alemkenberihun@gmail.com

Phone number: +251918707070/0933032021

 



Age and growth of Nile tilapia, Oreochromis niloticus from Lake Hayq were studied from June 8, 2022 to June 7, 2023.  A total of 738 otoliths were collected from the shore, open water and river mouth sites of the lake for otolith macrozone analysis. Otoliths were ground and examined under a dissecting microscope at 7−40X magnification for the presence of translucent and opaque macrozones using a reflected light source. The age of the fish was determined from the total number of translucent macrozones counted in the otoliths considering the time of translucent zone formation. The collected samples ranged from 9.3 to 32 cm in total length (TL) and from 14 to 495 g in total weight (TW). However of the fish sampled, 87.7 % were ≤ 13 cm. The maximum life span of O. niloticus was 6 years. A strong relationship between otolith length and otolith weight (r2 > 0.88) was found in O. niloticus. The relationships between fish length and otolith (length) were (r2 > 0.92). In O. niloticus, otolith weight was found to be best correlated with fish weight (r2 > 0.81) and nearly the same correlation was discovered between otolith length and otolith weight. Oreochromis niloticus caught in Lake Hayq has asymptotic length (L∞ = 31 cm) and have a growth rate (k) 0.90/year, growth performance index (Ø′L =2.93 and scientific information related to growth parameters is one of the fundamental factors for population management in an aquatic area.