DNA barcoding reveals blend of silver catfishRhamdiaspecies from fish farms in Southern Brazil

Abstract

Rhamdia quelen is the most produced native freshwater fish in fish farms in South Brazil. Until recently, Rhamdia branneri and Rhamdia voulezi were synonyms of R. quelen, and all the species are commercialized as silver catfish (locally called jundiá or bagre sapo) by the aquaculture industry. In fact, because these species are morphologically very similar, interspecific crosses easily might occur in fish farming. We employed standard DNA barcoding to identify jundiá molecular operational taxonomic units (MOTUs) in fish cultivated and commercialized in the industry and in possible escapees in the natural environment in southern Brazil. We analysed 48 individuals from six fish farms and 48 individuals from three rivers (Uruguay, Benedito Novo and Itapocu Rivers) using the mitochondrial cytochrome oxidase subunit I (COI). Four MOTUs were identified based on the estimated optimum threshold (OT = 0.77), and these MOTUs were concordant with Bayesian Inferece (BI) and Neighbour‐Joining (NJ) trees. Our results support the existence of at least three species in our dataset: R. branneri, R. voulezi, and R. quelen 1 and R. quelen 2. The interspecific genetic divergence ranged from 1.1% to 5.1% (mean = 3.5%), and the intraspecific distance ranged from 0% to 1.4% (mean = 0.24%). The presence of cultivated fish in the Uruguay and Benedito Novo Rivers provides evidence of genetic contamination in native populations. These results show the need to regulate aquaculture activities and to characterize the species and commercial lineages of silver catfish that are cultivated in South Brazil.

Population Genomics in Rhamdia quelen (Heptapteridae, Siluriformes) Reveals Deep Divergence and Adaptation in the Neotropical Region

“…In order to integrate the data from both mtDNA markers reported in previous studies [10,11,14,15,37], partial sequences of COI gene were analyzed in at least three specimens from each cytb mtDNA lineage (Rq2, Rq4 and Rq6, Ríos et al [14]) along with 126 other COI sequences retrieved from the GenBank (Supplementary File SIII). The COI gene was partially amplified using the universal DNA primers LCO1490 and HC02198 [38].…”

“…Alternatively, Rq6 distribution could be explained by dispersion associated with reclamation of habitat following glacial periods [6]. Surprisingly, Rhamdia branneri (Haseman, 1911) from the Iguaçu Basin [10,11] also belongs to the same Rq6 COI lineage. R. branneri is considered endemic of the Iguaçu River in the far northeast of LP-PM-AO [10,79].…”

“…Some of these lineages have dispersed widely during the post-glacial reclamation of habitat [6,7]. Among Neotropical silver catfish, Rhamdia quelen (Quoy and Gaimard, 1824) (Heptapteridae, Siluriformes) is distributed from the northeast end of the Andes mountain range to the central part of Argentina [8] and constitutes a valuable species exploited in artisanal fisheries and regional aquaculture [9][10][11]. Moreover, R. quelen has been proposed as a priority species for conservation in its southernmost distribution because of its cultural and economic value [12].…”

“…In the first systematic revision of the Rhamdia genus, more than 100 species were synonymized, 46 of which were synonymized with R. quelen [13]. Previous studies on this species based on mitochondrial DNA (mtDNA) data suggested different mtDNA lineages [11,14,15], while other authors provided morphological evidence supporting sister species previously included in R. quelen [10,16]. Those studies were based on two different mitochondrial markers, cytochrome b (cytb) and cytochrome c oxidase subunit I (COI); however, analyses at different geographical scales based on both markers have not been performed to date.…”

Multiplex microsatellite PCR panels and their application in genetic analyses of bighead carp (Hypophthalmichthys nobilis) and silver carp (H. molitrix)

“…Accurate species diagnosis is an important prerequisite for studies of fish ecology, and population biology (Hofmann, Knebelsberger, Kloppmann, Ulleweit, & Raupach, 2017; Scaranto, Ribolli, & Zaniboni‐Filho, 2018). H. nobilis and H. molitrix are genetically isolated and occur in sympatry within their native range (Lamer et al, 2015).…”