Assessment of river ecological health status and interbasin water transfer potential: Case study of Luapula River Basin in Zambia

Abstract

Water transfer is one mechanism for meeting increasing water demand in water-stressed areas. However, moving water from one area to another often disturbs the ecosystem including the fisheries biodiversity and growth patterns. Thus, when contemplating water transfer, baseline information on the status of the fisheries biodiversity and condition is cardinal for sustainable fisheries management during and after water transfer implementation. This work aimed at investigating the current fisheries condition (biodiversity, weight length relationship and condition factor) of the Luapula River Basin (LRB) to explore potential and implications for future interbasin water transfer on the basin fisheries. The fishes were sampled during the 2022/2023 dry and wet season at selected sites in LRB. Biodiversity indices, fish weight/length relationship and condition factor were used to describe the fish biodiversity, growth patterns and wellbeing which described the status of the aquatic condition of the donor basin. Species Richness, Shannon Diversity Index, Simpson Index and Evenness ranged between 0.8902 and 1.664, 0.9167 to 2.1437, 0.4416 to 0.8683 and 0.4172 to 0.8940 respectively. The growth coefficient (b) ranged from 1.223 to 3.755 indicating negative and positive allometric growth. The condition factor ranged between 0.692 and 2.218. Thus, it can be said that the LRB has good fish biodiversity albeit with some species showing dominance, normal growth pattern and wellbeing showing bias towards undisturbed habitats and physiological state. As such, this status quo of LRB needs to be maintained prior to, during and after IBWT implementation.