The current population genetic status of oreochromis niloticus (linnaeus, 1758) along the malagarasi river, Tanzania
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Date
2024
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Elsevier
Abstract
In East African countries, the O. niloticus species is the second most important fish species in terms of economic
significance. However, localized overfishing, habitat degradation, and hybridization have resulted in pop
ulations’ decline that poses a threat to this species in this area. This study assessed the genetic diversity, pop
ulation structure, demographic history, and effective population size of this species along the Malagarasi River.
Comparisons were made between the population genetic structure and demographic history of populations of
this species from Malagarasi River and other sites in the East Africa (EA) region. The study used COI gene se
quences isolated from O. niloticus species collected along the Malagarasi River and COI gene sequences of this
species from other sites in the EA region. The populations of O. niloticus from the Moyowosi had the highest
haplotype diversity (0.80 ± 0.06) and nucleotide diversity (0.72 ± 0.41 %). At Ilagala, the lowest haplotype
diversity (0.44 ± 0.13) and nucleotide diversity (0.16 ± 0.13 %) were found. Fixation index (Fst value) analysis
resulted into significant genetic difference among the populations along Malagarasi River (Fst = 0.08419, P <
0.01). The Fst values and minimum spanning haplotype network revealed genetic break between population of
O. niloticus from the Malagarasi River and other sites of the EA region. In order to ensure the sustainable
exploitation of O. niloticus and other threatened fish species along the Malagarasi River, these findings urge for
strengthening the implementation of fisheries laws, particularly in areas where samples exhibit low genetic
diversity.
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Keywords
Population genetics, Genetic diversity, Demographic history, Oreochromis niloticus, Malagarasi river