Characterisation of Oreochromis niloticus fish species of Lake Kariba, Zambia, using morphological, meristic and genetic methods

Abstract

This study aimed at characterising Oreochromis niloticus fish species of Lake Kariba and was premised on the hypothesis that there are different types of O. niloticus fish species in Lake Kariba. Oreochromis niloticus fish specimens (n = 409) were collected from both culture fisheries (Yalelo fishery, Fwanyanga fishery and Choombwe fishery) and capture fisheries (Siavonga and Sinazongwe) based at Lake Kariba from April to November 2020. All the collected fish samples were used for phenotypic characterisation, while 98 were used for genetic characterisation. A total of 23 morphometric measurements and seven meristic counts were used to generate morphometric data which were analysed using multivariate analysis. In order to delineate the sampled specimens, dendrograms were generated. Further, microsatellite data were generated from 98 samples using a panel of five microsatellite markers and analysed using microsatellite toolkit, GenAIEx, Fstat and LIAN software. Meristic results of culture fisheries showed that the sampled fish could be characterised into two strains, while samples from capture fisheries could be characterised into four strains. On the other hand, morphometric characterisation of fish from both culture and capture fisheries grouped the fish into three strains. In addition, population genetic analysis also showed that aquaculture farmers of Lake Kariba are rearing three populations of O. niloticus, while those from capture fisheries are composed of many distinct variant fish strains but can be roughly grouped into two types of O. niloticus fish species. The population of O. niloticus from the wild are genetically diverse, sub-structured with an absence of panmixia and are present in all fisheries. In conclusion, the fisheries understudy possessed potentially three strains of O. niloticus segregated in approximately three populations.

The morphological aspect of a brown tilapia compared to that of the Nile tilapia (Oreochromis niloticus)

“…Overall, the length-weight relationships in Nile tilapia species were reported differently, either as positive allometric (b > 3), negative allometric (b < 3), or isometric (b = 3). The Nile tilapia cultured in Bangladesh [19], Myanmar [20], India [22], Tanzania [23], and Zambia [24] were reported to have negative allometric growth of the length-weight relationship. In contrast, the Nile tilapia cultured in Thailand [25] and Kenya [26] had positive allometric ones.…”

Analysis of morphological differences in five large yellow croaker (Larimichthys crocea) populations

“…The species clustering tree was constructed to compare the distance between populations. 20 In formula: P 1 and P 2 are the discriminant accuracy rate (%), P is the comprehensive discriminant rate (%), O is the number of correctly discriminated large yellow croaker (tail), M is the number of measured large yellow croaker (tail). N is the number of large yellow croaker (tail); A i is the number of large yellow croaker (tail) correctly judged by the i group, B i is the number of large yellow croaker (tail) actually judged by the i group, and k is the number of groups (number).…”

Coculture of aquatic animals and paddy in brackish water: Evaluation of the growth of daily growth and morphometrics of tilapia (Oreochromis niloticus) as a fed species

“…Pengukuran bagian-bagian tertentu dari morfologi tubuh ikan merupakan metode paling sederhana dan langsung dalam mengidentifikasi karakteristik ikan (Makeche et al, 2022). Khusus untuk ikan nila, pengukuran karakteristik morfometrik telah dilaporkan dalam beberapa penelitian, baik dari hasil tangkapan maupun budidaya (Kwikiriza et al, 2023), namun morfometrik ikan nila dari sistem budidaya yang berbeda sejauh ini belum diketahui informasinya.…”

“…Beberapa penelitian terdahulu lebih banyak mengukur karakteristik morfometrik pada ikan nila hasil tangkapan. Selain itu, untuk pengukuran morfometrik ikan nila dari hasil budidaya umumnya pada ukuran-ukuran yang telah besar seperti yang dilaporkan oleh Ikpeme et al (2017), Kwikiriza et al (2023), Makeche et al (2022), dan beberapa penelitian lainnya. Variabilitas metode pemeliharaan pada beberapa penelitian terdahulu juga dapat menyebabkan bias jika dibandingkan dengan penelitian ini.…”