Current status of Cyprinids abundance and diversity and their potential for aquaculture production in Rwanda

Abstract

The present study was conducted to get a recent overview of native and exotic cyprinid species in Rwandan waters, focusing on the  abundance and the diversity and to identify those that may be used in Rwandan aquaculture industry. Seven hydrological areas were  sampled during ten months in 2019-2020. Species identification was done by morphometrical analysis and using key guides. Eight cyprinid species were recorded. Lower Akagera was the most diversified area in cyprinid species (with H’=1.38±0.1 and D=0.29±0.0) and  was significantly different (p˂0.05) compared to other hydrological areas. This area also showed higher fishes’ abundance. Beta diversity  displayed higher similarity between Kigali water bodies and upper Akagera (SI=0.8), upper Akagera and Akanyaru (SI=0.667), upper  Akagera and lower Akagera (SI=0.571). Dissimilarity was total; BCI=0.0 between northern lakes and Lake Kivu. Cyprinus carpio  (RD=60.1±4.8, F=0.57±0.0) and Enteromius cercops (RD=18.1±2.0, F=0.43±0.0) were significantly dominant and frequent (p˂0.05) compared  to other cyprinid species. Captures of common carps were significant and most of the specimens were of big size. Considering  their total length and large body weight (TL=33.8±3.13cm, BW=3.0±2.12kg), the exotic species Cyprinus carpio revealed to be  adapted to Rwandan ecological conditions and it can be used in the aquaculture industry throughout the country. In parallel, the native  cyprinids Labeobarbus altianalis (TL=32.2±8.32cm, BW=2.5±1.86kg) and Labeo victorianus (TL=26.5±4.37cm, BW=0.5±0.12kg) were  recorded with big size, they can also offer potentiality in aquaculture sector and further studies on induced spawning and adaptability in   aquaculture of these cyprinid species are necessary.