African freshwater eel species (Anguilla spp.) identification through DNA barcoding.

Abstract

Freshwater eels (Anguilla spp.) have a long and complex catadromous life cycle. This unique feature, coupled with difficulty in separating species based on morphology, makes them complex targets for conservation. In this study, we evaluate the utility of DNA barcoding using cytochrome oxidase I (COI) to delimit the four species of African eels found in the Western Indian Ocean region. We collected 75 individual fin clips from the four eel species (A. mossambica, n = 51; A. marmorata, n = 17; A. bengalensis, n = 6; A. bicolor, n = 2) in the rivers of KwaZulu-Natal, South Africa during 2016 - 2018. Phylogenetic analysis of the COI sequences recovered all four species as monophyletic. Barcoding gap analyses were performed and found that there was no overlap in inter- and intraspecific genetic distances. Consequently, the use of COI-barcoding as an identification tool was found to be reliable for identifying African eels to the species level, which suggests that this marker should be included in future environmental DNA or metabarcoding studies.