Molecular assessment of Gymnotus spp. (Gymnotiformes: Gymnotidae) fishing used as live baitfish in the Tietê River, Brazil

Abstract

The capture of live bait for sport fishing is an important activity for fishing communities. The main species used for this purpose are members of the genus Gymnotus, which comprises numerous species of cryptic nature that are difficult to identify based on external morphology. The aims of this work were to identify through partial sequences of the COI gene Gymnotus species fished in the Jacaré-Guaçu River, SP, and to develop a molecular diagnostic approach using PCR-RFLP to identify these species. Partial COI sequences were compared to those of other species deposited in GenBank. The sequences were assessed in the NEBCutter program to determine restriction sites in the sequence and the enzymes to be tested. Phenetic analysis performed by Neighbor-Joining method showed that the specimens sampled belong to two species preliminary identified here as G. cf. sylvius and G. cf. cuia, with G. cf. sylvius accounting for 95.2% of the individuals sampled. The enzymes NlaIII and SacI generated fragments that allowed distinguishing the Gymnotus species using PCR-RFLP. This analysis can be used to accurately identify these species, which is fundamental for monitoring Gymnotus fishing and assessing the conservation of this genetic resource.

Diversification of Neotropical Freshwater Fishes

“…Quantitative morphometric and multilocus genetic data sets have now been developed to study geographic variation within and among closely related species in many NFF taxa (e.g., Crampton et al 2016, Melo et al 2016a, Silva et al 2016, Craig et al 2017, Burress et al 2018b). These data sets have been used to delimit species boundaries (e.g., Bagley et al 2015, Faria-Pereira et al 2019, Serrano et al 2019 and to identify cryptic and pseudocryptic species (e.g., Melo et al 2016b). The emerging use of genome-wide markers [e.g., ultraconserved elements (UCEs), restriction site-associated DNA sequencing (RADseq) markers] has expanded the number of loci used in phylogenetic and phylogeographic analyses of NFF taxa into the thousands (Chakrabarty et al 2017, Alda et al 2018, Roxo et al 2019.…”

Gymnotus paraguensis, a Good Example of Phenotypic Plasticity in the Pantanal Biome, Brazil

“…29 It thus seems likely that many studies have analyzed different species, identified erroneously as G. carapo, generating parameters distinct from those expected to represent a single species. Inconsistencies have already been reported in the regulation of Gymnotus species harvested for live bait, such as the fact that the legislation refers only to G. carapo in the Tietê River (Paraná basin), whereas Faria-Pereira et al 69 had identified only Gymnotus cf. sylvius and Gymnotus cf.…”

Archolaemus janeae (Gymnotiformes, Teleostei): First insights into karyotype and repetitive DNA distribution in two populations of the Amazon

“…The cytogenetic studies published for Gymnotiformes have given insight into the diversity and karyotype evolution of this order (Cardoso et al., 2015 ; Fernandes, Baumgärtner, et al., 2017 ; Fernandes, Paiz, et al., 2017 ; Faria‐Pereira et al, 2019 ; Milhomem et al., 2012 ; Sene et al., 2014 ; Silva et al., 2008 ; da Silva et al., 2016 ; da Silva et al, 2014 ). The diploid chromosome number (2 n ) ranges from 2 n = 24 in Apteronotus albifrons (Linnaeus, 1766) (Apteronotidae; Fernandes, Paiz, et al., 2017 ; Takagui et al., 2017 ) to 2 n = 74 in Rhabdolichops cf eastwardi Lundberg, Mago‐Leccia, 1986 (Sternopygidae; Suárez et al., 2017 ).…”