Kassem et al., M. (2023). An Experimental Trammel Net in the River Nile, Aswan, Egypt Influencing the Age and Growth of the Nile tilapia Oreochromis niloticus (Linnaeus, 1758). Egyptian Journal of Aquatic Biology and Fisheries, 27(2), 155-171. doi: 10.21608/ejabf.2023.291672
Mahmoud A. H. Kassem et al.. "An Experimental Trammel Net in the River Nile, Aswan, Egypt Influencing the Age and Growth of the Nile tilapia Oreochromis niloticus (Linnaeus, 1758)". Egyptian Journal of Aquatic Biology and Fisheries, 27, 2, 2023, 155-171. doi: 10.21608/ejabf.2023.291672
Kassem et al., M. (2023). 'An Experimental Trammel Net in the River Nile, Aswan, Egypt Influencing the Age and Growth of the Nile tilapia Oreochromis niloticus (Linnaeus, 1758)', Egyptian Journal of Aquatic Biology and Fisheries, 27(2), pp. 155-171. doi: 10.21608/ejabf.2023.291672
Kassem et al., M. An Experimental Trammel Net in the River Nile, Aswan, Egypt Influencing the Age and Growth of the Nile tilapia Oreochromis niloticus (Linnaeus, 1758). Egyptian Journal of Aquatic Biology and Fisheries, 2023; 27(2): 155-171. doi: 10.21608/ejabf.2023.291672
An Experimental Trammel Net in the River Nile, Aswan, Egypt Influencing the Age and Growth of the Nile tilapia Oreochromis niloticus (Linnaeus, 1758)
Oreochromis niloticus, a widely distributed and commercial fish in Egypt, needs continuous updating and studying. The current work aimed to study the length-weight relationship, condition factors, age and growth of O. niloticus, and the effect of fishing gear on fish stocks. A total of 608 O. niloticus specimens were collected by three modified trammel nets with different mesh sizes (56, 64 and 76 mm) in percentages of about 49.8%, 47.4% and 2.8%, respectively. Total length (TL) ranged from 12 to 24.3cm, and total weight ranged from 42.8 to 253g for all samples. The exponent "b" of the length-weight relationships was "3" for females (b = 2.79), males (b = 2.69) and all samples (b = 2.66), reflecting the negative allometric mode of growth. The highest condition factors were found in February for females and January for males and combined sexes, and all values were >1.0. The age of O. niloticus was determined to be 4 years old. Von Bertalanfi's growth constants are L = 28cm; K = 0.28 y-1, and to = -1.9. Regarding the age differences with variation in mesh sizes, it has been pointed out that the use of median and large mesh sizes is important to avoid small fish in a lower age group, which is considered for fisheries management and conservation.
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