DNA barcoding affirms the presence of invasive Parachanna obscura and new records of some species in the Mweru-Luapula fishery

Abstract

DNA barcoding has recently been instrumental in identifying both invasive and undetected species in aquatic environments. This study aimed at analysing collected fish fin clips to ascertain the identity of native species and the Parachanna species that have invaded the Mweru-Luapula (ML) fishery of Zambia. The identification process was carried out through field phenotypic analysis using species guides and DNA barcoding, with the mitochondrial DNA (mtDNA) cytochrome C oxidase 1 (COI) gene fragment. Of the 28 specimens for which DNA was successfully PCR amplified, five matched the reference sequences of species and 22 matched the reference sequences of genera on the NCBI GenBank. Five unexpected species, namely Oreochromis niloticus, Coptodon zillii, Mormyrus kannume, Thoracochromis buysi and Tylochromis polylepis were identified. The study further affirmed the presence of invasive Parachanna obscura in the fishery and its interconnected water bodies. Parachanna obscura invaded the fishery through annual flooding from aquacultural facilities in the Democratic Republic of Congo (DRC). There is a need to investigate this invasion further by using large sample sizes and also by applying the gonadosomatic index (GSI) to determine invasive species occupancy and impact on native species throughout the fishery. This study provides a platform for further detailed taxonomic verification and species inventory of the entire ML fishery. This will facilitate the development of a viable and sustainable strategy to appropriately curb the impact of invasive species, and will thus contribute to the conservation of the ML aquatic biodiversity.