The effect of flooding phase and water quality on the littoral fish species of the Zambezi/Chobe floodplain was assessed between March 2017 and February 2018. Using the similarity percentage analyses (SIMPER), a 61.9% dissimilarity was detected in fish assemblages among the four flooding phases of the Zambezi/Chobe floodplain (rising, peak, recession and low flooding phase). Cichlids (63.1%) were the most dominant taxa during the peak flooding phase while cyprinids were dominant during the rising (40.7%), recession (45.3%) and low flooding phases (40.9%), respectively. Juveniles of the two commercially important species, Oreochromis andersonii and Coptodon rendalli, were among the four abundant species across the four flooding phases of the Zambezi/Chobe floodplain. Higher densities of these two species were in synchrony with the peak flooding phase, characterised by high levels of dissolved oxygen (5.7 ± 1.0 mg/L), neutral pH (7.9) and moderate water temperature (27.6 ± 1.1°C). During the flood recession phase, a severe decline in juvenile of the commercially important species (O. andersonii and C. rendalli) coincided with fish migration off the littoral zone into the main river at a mean size between 70 and 80 mm SL. Generally, the observed variations in the fish species composition during the different stages of flooding might reflect the influence of water quality and water volume to sustain large fish assemblages on the littoral zone of the Zambezi/Chobe floodplain. Any change in the natural flow and reduction in water volume of the Zambezi/Chobe floodplain might negatively affect the recruitment of juvenile fish into adult populations.

中文翻译：

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水位和水质对赞比西河/乔贝河漫滩滨海地区小型和小型鱼群的影响

在2017年3月至2018年2月之间，评估了淹水期和水质对赞比西河/乔贝河漫滩的沿海鱼类物种的影响。使用相似度百分比分析（SIMPER），在四种洪水中鱼群中发现了61.9％的相异性赞比西河/乔贝河洪泛区的各个阶段（上升，高峰，衰退和低洪泛阶段）。在洪灾高峰期，丽鱼科鱼（63.1％）是最主要的分类单元，而在洪水高峰期（30.7％），衰退（45.3％）和低洪灾阶段（40.9％），塞浦路斯是主要的分类单元。两种商业上重要的物种，即Oreochromis andersonii和Coptodon rendalli的幼体，是赞比西河/乔贝河漫滩的四个洪水阶段的四个丰富物种之一。这两个物种的较高密度与洪峰高峰相同步，其特征在于高水平的溶解氧（5.7±1.0 mg / L），中性pH（7.9）和适度的水温（27.6±1.1°C）。在洪水衰退阶段，商业上重要的物种（O. andersonii和C. rendalli）恰好是鱼类从沿海地区迁移到主要河流的平均大小，范围在SL至70毫米至80毫米之间。通常，在洪水的不同阶段观察到的鱼类物种组成的变化可能反映了水质和水量的影响，以维持赞比西河/乔贝河漫滩沿岸带的大型鱼类种群。赞比西河/乔贝河漫滩的自然流量的任何变化和水量的减少都可能对幼鱼向成年种群的招募产生负面影响。