Genetic diversity and population history ofTanichthys albonubes(Teleostei: Cyprinidae): Implications for conservation

Abstract

Tanichthys albonubes is a cyprinid fish of South China and North Vietnam. Although this species has been sold worldwide in the aquarium trade for more than a century, it is listed as a second‐class state‐protected animal in China and classified as ‘extinct in nature’ in the China Red Data Book. To investigate the population history of T. albonubes and evaluate the genetic conditions among the wild and hatchery populations, mitochondrial genes (mtDNA, 2032 bp from the d‐loop and cyt b), nuclear genes (nuDNA, 2241 bp from RAG1 and ENC1) and 13 microsatellite loci were used to assess the genetic structure throughout the range of this species. In total, 358 specimens were collected from three hatcheries and all known wild populations. This study found that the discordant population structure among these genetic markers was accounted for by differences in the effective population sizes. The results indicated that (1) the three hatchery stocks originated from a single source in China and that the hatchery stock in China maintained almost all the T. albonubes genetic diversity in the downstream reaches of the Pearl River; (2) the wild population near Baiyun Mountain originated from hatchery releases; (3) the population history reflects the complex geological history of South China; and (4) the habitat destruction and fragmentation that have resulted in small and isolated populations may have shaped the genetic structure of T. albonubes. The low‐level genetic diversity of T. albonubes supports the need for conservation interventions. The geographically distinct genotypes indicate a need for the development of management strategies directed towards the conservation of localized populations. The genetic status of all populations, including the hatchery stocks, should be evaluated and monitored continuously.

Two new species of Tanichthys (Teleostei: Cypriniformes) from China

“…Previous data may have been obtained by an inaccurate counting method. The sampling locality of the lineage "DX" (from Dongxing City, Guangxi Province) in Zhao et al (2018) and Li et al (2020), which is the same as the type locality of T. albiventris (coded JP in the present study), was provided by the first author of this study via Dr. Hung-Du Lin who was the corresponding author of Zhao et al (2018). Li et al (2020) reported eight branched anal-fin rays for this population based on the examination of 30 specimens, whereas in the present study, the number of branched anal-fin rays of the JP population is 9-10 (mostly 9), and that of the HZ population of T. albiventris from an adjacent basin is 9-11 (mostly 9).…”

“…Tanichthys comprises four species, including Tanichthys albonubes Lin, 1932 (white cloud mountain minnow), Tanichthys kuehnei Bohlen, Dvořák, Thang & Šlechtová, 2019, Tanichthys micagemmae Freyhof & Herder, 2001, and Tanichthys thacbaensis Nguyen & Ngô, 2001. Unlike the other three species restricted to specific river basins with a narrow geographic distribution in northern and central Vietnam, T. albonubes has a wide distribution ranging across several different basins (the River Pearl and several small coastal rivers) in southern China (including Guangdong, Guangxi, Hainan and Hong Kong) and northern Vietnam (Quang Ninh Province) (Weitzman & Chan 1966, Pan 1991, Chen 1998, Kottelat 2001, Yi et al 2004, Chan & Chen 2009, Li & Li 2011, Zhao et al 2018. Recent molecular studies indicated that each of the wild populations of T. albonubes was monophyletic with significant genetic differentiation among them (Luo et al 2015, Zhao et al 2018.…”

“…Unlike the other three species restricted to specific river basins with a narrow geographic distribution in northern and central Vietnam, T. albonubes has a wide distribution ranging across several different basins (the River Pearl and several small coastal rivers) in southern China (including Guangdong, Guangxi, Hainan and Hong Kong) and northern Vietnam (Quang Ninh Province) (Weitzman & Chan 1966, Pan 1991, Chen 1998, Kottelat 2001, Yi et al 2004, Chan & Chen 2009, Li & Li 2011, Zhao et al 2018. Recent molecular studies indicated that each of the wild populations of T. albonubes was monophyletic with significant genetic differentiation among them (Luo et al 2015, Zhao et al 2018. They were further considered as different cryptic species (Li et al 2020).…”

Genetic Structure and Diversity of the Yellowbelly Threadfin Bream Nemipterus bathybius in the Northern South China Sea

“…Accordingly, our study examined the population genetic structure and diversity of N. bathybius in the northern South China Sea using the genetic variability of the mitochondrial DNA (mtDNA) cytochrome b gene (cyt b), with the aim of revealing its demography. The sequences of mtDNA cyt b are usually used to reconstruct demographic history and animal phylogeography (e.g., Garra orientalis [31], Tanichthys albonubes [32], Neocaridina [33], Scatophagus argus [34], Capra pyrenacia pyrenacia [35]).…”

Descriptions of six new species in White Cloud Mountain minnow Tanichthys albonubes complex (Cypriniformes: Tanichthyidae) in southern China

“…T. albonubes was first discovered on White Cloud Mountain in Guangzhou City, Guangdong Province, South China (Lin, 1932), and was thought to be monotypic and endemic to the Pearl River Delta region (Chen, 1998). Since the 21st century, wild populations of T. albonubes have been continuously discovered in many sites, including Guangzhou, Huizhou, Luhe and Qingyuan in Guangdong Province (Chen, 2010; Yi et al ., 2004; Zhao et al ., 2018), Guiping (Li & Li, 2011) and Dongxing in Guangxi Province, Hainan Island (Chan & Chen, 2009) and north‐east Vietnam (Kottelat, 2001). Among these newly discovered populations, the population of Qingyuan was confirmed to have originated from hatchery release (Zhao et al ., 2018; Li et al ., 2020b) and hence the original Qingyuan population described by Zheng (1989) may have become extinct.…”