Browsing by Author "Namitaa, Tukelo Lavinia"

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    A comparative study on the fish species composition, diversity and catch rates among the fisheries reserves on the Zambezi and Kwando rivers, Zambezi region
    (University of Namibia, 2025) Namitaa, Tukelo Lavinia; Mfune, John K. E.
    The Zambezi and Kwando Rivers in northeastern Namibia support vital floodplain fisheries that provide food, income, and seasonal employment for many local communities. However, increasing pressure from overfishing, habitat degradation, and climate change has highlighted the need to establish fisheries reserves to promote sustainable resource use. This baseline study evaluated fish assemblages, specifically species composition, diversity, and catch per unit effort (CPUE); across five fisheries reserves located along the Zambezi River (Sitwela, Kabweza, and Makangala) and the Kwando River (Luhingi and Qhuqhumupa). Gillnet surveys using both experimental and monofilament gillnets were conducted between 13 November and 13 December 2021. A total of 3,360 individual fish, representing 32 species, were captured. On the Zambezi River, Makangala had the highest species richness with 24 species, followed by Sitwela with 21 species, and Kabweza with 20. On the Kwando River, Luhingi recorded 17 species, while Qhuqhumupa had 12. There was no statistically significant difference in species diversity among the reserves (H(4)=8.268, p=0.082). However, overall CPUE (by weight) varied significantly between sites (H(4)=46.621, p<0.001), with Luhingi showing the highest CPUE (0.704±0.78 kg/set) and Kabweza the lowest (0.209±0.14 kg/set). Significant differences in individual CPUE were observed for two commercially important species: Clarias gariepinus(H(4)=26.783, p<0.001) and Clarias ngamensis (H(4)=17.967, p=0.001), while no significant variation was found for Serranochromis macrocephalus (H(3)=0.260, p=0.967). Similarly, mean fish sizes for C. gariepinus (H(4)= 25.850, p<0.001) and C. ngamensis (H(4)=14.660, p=0.005) differed significantly across sites, whereas no difference was noted for S. macrocephalus (H(3)=0.779, p=0.885). Regression analysis showed that temperature had no effect on fish catch rates. However, reserve size explained 14% of the variation in catch rates. These spatial differences in catch rates for key commercial species may be influenced by factors such as the degree of protection, age, and size of the reserves. In particular, higher CPUEs in the Kwando River reserves may be attributed to stronger protection measures and longstanding conservation awareness compared to the more recently established reserves along the Zambezi River. These findings underscore the need for tailored, site-specific management strategies to ensure the sustainability of fish populations across all five newly established fisheries reserves in the region