This investigation and critical revision of the ichthyofauna of Tajikistan is the result of two nationwide surveys completed by the authors in 2017 and 2019 combined with an analytical examination of previous studies. The ichthyofauna of Tajikistan includes 60 species, of which 44 are native and 15 are nonnative, while one species (Cyprinus carpio) is represented by populations of native and alien origin. Seven species recorded in neighboring countries could potentially be found in Tajikistan, 12 introduced species are nonnaturalized, two were erroneously identified as belonging to the ichthyofauna of Tajikistan, and two are extinct. The current fish fauna is represented by eight orders (Acipenseriformes, Cypriniformes, Cyprinodontiformes, Gobiiformes, Perciformes, Salmoniformes, Siluriformes, and Synbranchiformes) and 18 families (Acipenseridae, Acheilognathidae, Channidae, Cobitidae, Cottidae, Cyprinidae, Esocidae, Gobiidae, Gobionidae, Leuciscidae, Nemacheilidae, Odontobutidae, Percidae, Poeciliidae, Salmonidae, Siluridae, Sisoridae, and Xenocyprididae), of which the largest number of species belong to Leuciscidae (14 species), Nemacheilidae (13 species), and Cyprinidae (9 species). Significant changes in the fish fauna occurred in the 20th century due to anthropogenic factors and climate change. Water diversion for irrigation and construction of canals and reservoirs led to changes in the hydrological regime, which, combined with illegal fishing and overharvesting dramatically affected the abundance of at least eight species and led to the extinction of two, Acipenser nudiventris and Pseudoscaphirhynchus fedtschenkoi. Massive introductions of commercial fish species in the 20th century led to an increase in the alien fauna to 16 species.
INTRODUCTION
From the first studies in 1841 until the mid-20th century, more than 20 researchers have studied fishes within the territory of modern-day Tajikistan, many of whom left behind collection materials and a number of ichthyological notes, which were summarized by Nikolskiy (1938: 49). Comprehensive fundamental studies of the ichthyofauna of Tajikistan were published in the first half of the 20th century (Berg, 1905; Nikolskiy, 1938; Shaposhnikova, 1950). However, since the second half of the 20th century, events have occurred that have greatly affected the ichthyofauna of the region. The most striking of these has been the drying of the Aral Sea due to excessive diversion of water for irrigation, which led to restructuring of ecosystems in the lower reaches of the Amu Darya and Syr Darya, significantly affecting anadromous and semi-anadromous fish species (Aladin and Potts, 1992; Akhrorov, 2006). Extensive construction of irrigation systems, including dams on rivers and an elaborate network of canals changed the living conditions of fishes and affected their natural distribution (Salikhov and Kamilov, 1995). Large-scale “improvement” of the fishery complex, which involved massive introductions of fishes from the Far East, led to the emergence of sustainable populations of species useful for aquaculture and many invasive fish species (Vundtsettel, 1994; Akhrorov, 2006). In addition, poaching and overfishing have significantly increased during the past 30 years (Kustareva and Naseka, 2015; Mitrofanov and Mamilov, 2015; Sheraliev and Peng, 2021).
The purpose of this work is to identify the current ichthyofauna by conducting nationwide ichthyological surveys including the use of modern molecular techniques, to critically analyze previous studies, and to consider changes that have occurred since the mid-20th century.
MATERIALS AND METHODS
Geographical Characteristics of Tajikistan
Tajikistan is the smallest and most mountainous country in Central Asia (fig. 1). More than 90% of its territory is occupied by the mountain systems of the Tien Shan and Pamir ranges, and is located almost entirely within a zone of internal flow, primarily draining to the inland Aral Sea via the Syr Darya in the north and the Amu Darya in the south. The central part of Tajikistan belongs to the Zeravshan River basin, which previously flowed into the Amu Darya, but currently, due to diversion of water for irrigation, does not reach it. About half the length of the Syr Darya riverbed within Tajikistan is dammed by the Kairakkum reservoir. The Tarim basin is represented by a small glacial catchment of the Markansu River in the northwest of the country. There is a large high-mountain lake, Karakul, which also has a small endorheic drainage that is hypothesized to have made its last contact with the Amu Darya basin approximately 12–15 thousand years ago (Komatsu and Tsukamoto, 2015). The highest point where we encountered fish (Triplophysa stolickai sensu lato) is located in the basin of this lake (elev. 4050 m; fig. 2G).
The majority of the territory of Tajikistan is occupied by mountain ranges—the Pamir in the east (mountain plateau 3000–4000 m with peaks to 7649 m elev.) and the western spurs of the Pamir-Alai Mountain system in the central part, with peaks up to 7495 m (Antropov, 1959). In the southwestern part of the country there is a plain crossed by small mountain ranges. In the northern region there is the western portion of the Fergana Valley. Photos of various biotopes are presented in figure 2.
FIGURE 1.
Map showing the collecting localities in Tajikistan; associated data is provided in the appendix. Red circles: localities with fishes; yellow circles: localities without fishes.
The ichthyofauna of Tajikistan is represented by species inhabiting the mountainous areas, foothills, and flat areas within the upper reaches of the Amu Darya, Syr Darya, and Zeravshan drainages. Though all three of these habitat types are dispersed throughout the country, the vast majority of the country consists of mountainous topography, whereas the foothills and low-lying flat areas generally characterize the region in the southwest and northwest portions of the country (fig. 1).
The mountainous regions dominate the entirety of the eastern portion of the country and they make up a large swath of the middle portion of the country as well, from the western border with Uzbekistan to the eastern border with Afghanistan, separating the two largest low-lying areas in the north and south. Water temperatures here are extremely cold, as it consists largely of glacial runoff, and flows swiftly through steep canyons. As is typical for high-elevation cold-water streams, diversity is generally low. These habitats are dominated by species adapted to high flow environments and those that require cold, well-oxygenated waters, such as Triplophysa, Salmo, and various schizothoracines.
FIGURE 2.
Examples of collecting sites in Tajikistan. A, Syr Darya River at Khodjent (locality 4); B, Kafirnigan River, 12 km from its confluence with the Amu Darya River (locality 8); C, Shirkent River (locality 11); D, Vakhsh River downstream Bokhtar (locality 18); E, Muksu River at Sartala (locality 38); F, Pamir River (locality 45); G, Akbaital River (locality 51); H, Lake Karakul at Karakul (locality 52).
The foothills of these ranges still tend to have cold water (though not in all cases), and are still dominated, though to a lesser extent, by those cold-water-adapted species. Again, fishes of the subfamily Schizothoracinae and members of the genus Triplophysa occur here. Toward the base of the foothills, fish diversity begins to increase to include some additional nemacheilid loach species, minnows, and sisorid catfishes. These areas have varying flow rates and variable temperatures depending on their sources and whether or not they have been impounded upstream.
Despite being the smallest ecoregion in area the lowland valleys of Tajikistan offer the country's greatest diversity of fishes. These lowland areas are characterized by slower-flowing, typically warmer (though not in all cases) water, crossing through plains and valleys at the base of the large mountain ranges upstream. They have greater variety in habitat types, thermal heterogeneity, and more nutrient-rich aquatic communities. Rivers and streams here are more diverse and represent an array of minnows, catfishes, loaches, and more; they once accommodated a notable diversity of sturgeons, many of which are highly imperiled or extinct now. These areas are also rich in agriculture and tend to be more hospitable to human settlement and more developed than the mountainous parts of the country. The two largest cities in Tajikistan, Dushanbe and Khujand, are in these areas. Our data indicate that these areas are also the most susceptible to invasive species.
Data Collecting, Sampling, Species Identification
Two main approaches were used to assemble the data set for the current checklist. First, we analyzed the literature. Secondly, we studied our own material collected during two expeditions: in August and September of 2017 and June and July of 2019. We surveyed 52 localities spanning nearly the entirety of the accessible portions of the country (fig. 1). Also used were data collected by one author (N.M.) in the Tigrovaya Balka Nature Reserve (lower reaches of the Vakhsh River) in 2003–2018.
Fish were caught using frame nets, gill nets, seins, cast nets with a mesh of 5–8 mm, and, on occasion, hook and line. After catching, fish were euthanized with a solution of clove oil, primary identification of the species was carried out, and intravital photographs were taken with Canon EOS 70D and Nikon D5300 cameras. Photographs of some fish species are presented in figures 3–5. A piece of fin was cut from some specimens and placed in 96% ethanol to extract DNA in the laboratory. Next, the specimens were placed in 4% formalin for fixation and transportation. Then, in the laboratory, specimens were rinsed under water and placed in a 70% ethanol solution. Also in the laboratory, literature was used to identify species (Nikolskiy, 1938; Berg, 1949; Coad and Bogutskaya, 2012; Bogutskaya et al., 2013; Thoni et al., 2017; Sheraliev and Peng, 2021). DNA barcoding was also used to identify some species. In particular, the fishes of the genera Glyptosternon McClelland, 1842, Sabanejewia Vladykov, 1929, and Triplophysa Rendahl, 1933, were processed for cytochrome c oxidase I subunit (COI, length of fragment: 629 bp; GenBank acc. nos. PP990746-51, PQ249623), while Schizopygopsis Steindachner, 1866, was processed for cytochrome b (cytb: 1118 bp; GenBank acc. nos. PP993467–68). The DNA sequences were analyzed to find the most closely related taxa using the BLAST service of NCBI by default parameters ( https://www.ncbi.nlm.nih.gov/). The genetic distances (uncorrected p-distance) were calculated using the MEGA7 program (Kumar et al., 2016).
FIGURE 3.
Examples of salmonid and cyprinoid species of Tajikistan. A, Salmo oxianus (Aguyurma River, locality 35); B, Capoetobrama kuschakewitschi (Kafirnigan River, locality 9); C, Alburnoides holciki (Vakhsh River, locality 15); D, Rutilus lacustris (Syr Darya, locality 4); E, Alburnus taeniatus (Zeravshan River, locality 6). Scale bar: 10 mm.
Taxonomic names of orders and families are given according to Tan and Ambruster (2018) and Near and Thacker (2024), while species names are given according to Eschmeyer's catalog of fishes (Van der Laan et al., 2024).
Material sampled by authors was deposited in the Field Museum of Natural History, Chicago (FMNH) and under provisional labels in the Ichthyological Collection at the Institute of Biology of Inland Waters of the Russian Academy of Sciences, Borok, Russia (IBIW_FS). Species occurrences from field research are presented on GBIF (Artaev et al., 2024).
ICHTHYOFAUNA OF TAJIKISTAN
Species Inhabiting Tajikistan
Below is an account of 60 species from 18 families known to occur in Tajikistan.
Family Acipenseridae
Pseudoscaphirhynchus hermanni (Kessler, 1877)
Scaphirhynchus hermanni Kessler, 1877: 190. Type locality: Amu Darya near Turtkul (Petroaleksandrovsk), Uzbekistan.
References for Tajikistan: Pseudoscaphirhynchus hermanni — Nikolskiy (1938: 71): Amu Darya and Panj near Panj (Baumanabad); Shaposhnikova (1950: map): flat zone and lower part of foothill zone of Amu Darya basin; Grischenko et al. (1998): lower reaches of the Vakhsh River.
Conservation status in Tajikistan: Endangered (Saidov, 2017); critically endangered (sensu IUCN; Mugue and Karimov, 2022a).
Distribution in Tajikistan: Possibly in the lower reaches of the Vakhsh River and in the Amu Darya.
Specimens examined: None.
Comments: The last actual finds in Tajikistan date to 1995–1997, when seven specimens were caught in the lower reaches of the Vakhsh River in the waters of the Tigrovaya Balka Nature Reserve (Grischenko et al., 1998). Ichthyological studies conducted by N. Mirzoev from 2005 to 2020 in the lower reaches of the Vakhsh River did not record the species.
FIGURE 4.
Examples of cyprinoid species of Tajikistan. A, Schizothorax sp. (Lake Yashilkul, locality 44); B, Schizopygopsis sewerzowi (Lake Yashilkul, locality 44); C, Schizopygopsis sewerzowi (Gunt River, locality 42); D, Gobio nigrescens (Zeravshan R., locality 6); E, Gobio lepidolaemus (Aksu River, locality 2). Scale bar: 10 mm.
Pseudoscaphirhynchus kaufmanni (Kessler, 1877)
Scaphirhynchus kaufmanni Kessler, 1877: 194. Type locality: Lower Amu Darya, Uzbekistan.
References for Tajikistan: Pseudoscaphirhynchus kaufmanni — Berg (1905: 31): Amu Darya, possibly up to the Pamir (Alichur); Nikolskiy (1938: 64), Berg (1948: 105): Amu Darya up to Somoni (Faizabadkala); Shaposhnikova (1950: map): flat zone and lower part of foothill zone of Amu Darya basin; Kovalev et al. (2014: 111): Vakhsh River.
Distribution in Tajikistan: Very rare; occurs in the lower reaches of the Vakhsh and possibly in the Amu Darya Rivers.
Conservation status in Tajikistan: Critically endangered (Saidov, 2017), critically endangered (sensu IUCN; Mugue and Karimov, 2022b).
Specimens examined: None.
Comments: The last actual find in Tajikistan was made in 2012 in the Vakhsh River (Kovalev et al., 2014).
Family Acheilognathidae
Rhodeus ocellatus (Kner, 1866)
Pseudoperilampus ocellatus Kner, 1866: 548. Type locality: Shanghai, China.
References for Tajikistan: Rhodeus ocellatus — Rasulov (2011: 535): Tajikistan; Afanasyev et al. (2020: 370): Syr Darya including Kairakkum reservoir.
Distribution in Tajikistan: Amu Darya basin (Kafirnigan River) and Syr Darya River (Khujand) (localities 4, 8, 10).
Specimens examined: IBIW_FS (n = 7) (Artaev et al., 2024).
Comments: An invasive species, accidentally introduced as a result of acclimatization of fishes from the Far East (Makeeva, 1976). Based on morphology (Akai and Arai, 1998; Li et al., 2020) we classify bitterlings from lower reaches of the Kafirnigan River and Syr Darya River near Khujand to this species (Artaev et al., 2024).
FIGURE 5.
Examples of catfish and nemacheilid species of Tajikistan. A, Glyptosternon cf. akhtari (Vakhsh River, locality 32); B, Triplophysa strauchi (Zeravshan River, locality 6); C, Paracobitis longicauda (Varzob River, locality 20); D, Sabanejewia aralensis (Kafirnigan River, locality 9); E, Triplophysa cf. daryoae (Dekhmai spring, locality 3); F, Triplophysa stolickai s. lato (Pamir River, locality 45). Scale bar: 10 mm.
Family Channidae
Channa argus (Cantor, 1842)
Ophicephalus argus Cantor, 1842: 484. Type locality: Chusan Island, China.
References for Tajikistan: Ophiocephalus argus warpachowskii — Rasulov and Karimov (2014: 40): Kairakkum reservoir. Channa argus — Afanasyev et al. (2020: 370): Kairakkum reservoir.
Distribution in Tajikistan: Kairakkum reservoir, plain rivers of the Amu Darya drainage.
Specimens examined: Numerous in fishermen's catches in Kairakkum reservoir. In 2003–2018, specimens caught (not preserved) in floodplain lakes of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Comments: An invasive species, accidentally introduced as a result of acclimatization of fishes from the Far East in the 1960s. In the early 1970s it appeared in the Kairakkum reservoir; in the late 1970s and early 1980s it spread to the lowland reservoirs of southwestern Tajikistan (Rasulov, 2011).
Family Cobitidae
Sabanejewia aralensis (Kessler, 1877)
Cobitis aralensis Kessler, 1877: 184. Type locality: Syr Darya River mouth, Kazakhstan; Amu Darya mouth, Uzbekistan.
References for Tajikistan: Cobitis taenia aralensis — Berg (1905: 205): Amu Darya, Syr Darya with tributaries, Zeravshan. Cobitis aurata aralensis — Nikolskiy (1938: 168): Syr Darya, Amu Darya up to Pamir; Berg (1949: 896): Syr Darya, Zeravshan up to Panjakent, Amu Darya up to Pamir mouth; Shaposhnikova (1950: map): flat zone and lower part of foothill zone of Amu Darya basin.
Distribution in Tajikistan: Amu Darya up to Pamir, Kafirnigan, Zeravshan, and Syr Darya basins (localities 9, 10, 17, 19, 29).
Conservation status in Tajikistan: Endangered (Saidov, 2017), not known (sensu IUCN).
Specimens examined: IBIW_FS (n = 6) (Artaev et al., 2024). FMNH: 145658, 151182, 151133, 151161, 151172, 151191.
Comments: Preliminarily assigned to Sabanejewia aurata (Filippi, 1863) by Kottelat (2012). COI p-distance between S. aurata from type locality basin and Tajikistan population (GenBank acc. nos. PP990746–47) is 1.3%. Similar results for COI were obtained for Uzbekistan populations of S. aralensis, while K2P-distance in cyt b achieved 2.1%–2.3% (Sheraliev and Kayumova, 2022). This level of genetic divergence may satisfy a species status for Cobitidae species as shown in Vasil'eva et al. (2020).
Family Cottidae
Cottus spinulosus Kessler, 1872
Cottus spinulosus Kessler, 1872: 47. Type locality: Khujand, Syr Darya, Tajikistan.
References for Tajikistan: Cottus spinulosus — Berg (1905: 229): upstream Syr Darya, Khujand; Nikolskiy (1938: 181): Syr Darya up to Khujand; Berg (1949: 1150): upstream Syr Darya; Sideleva (2021: 330): springs flowing into the Farkhad Reservoir near Khujand. Cottus spinolosus — Akhrorov (2006: 34): Tajikistan; Rasulov (2011: 337, 540): upstream Syr Darya.
Distribution in Tajikistan: Syr Darya basin.
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Mamilov and Karimov, 2020a).
Specimens examined: None.
Family Cyprinidae
Capoeta heratensis (Keyserling, 1861)
Scaphiodon heratensis Keyserling, 1861: 11. Type locality: Heri-rud at Herat, Afghanistan.
References for Tajikistan: Capoeta heratensis — Berg (1905: 57): (Zeravshan, upstream Amu Darya, Syr Darya basins). Capoeta capoeta — Afanasyev et al. (2020: 367): (Syr Darya downstream Kairakkum reservoir). Varicorhinus heratensis steindachneri — Nikolskiy (1938: 104): Syr Darya, Amu Darya. Varicorhinus capoeta heratensis natio steindachneri — Berg (1949: 683): upstream Amu Darya and Syr Darya, Zeravshan; Shaposhnikova (1950: map): foothill zone of Amu Darya basin.
Distribution in Tajikistan: Amu Darya and Zeravshan drainages (excluding highland parts), possibly Syr Darya (localities 28, 29, 31).
Conservation status in Tajikistan: Not known; not known (sensu IUCN).
Specimens examined: IBIW_FS (n = 5) (Artaev et al., 2024), in 2003–2018, specimens were also caught (not preserved) in lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
FMNH: 145655–56, 151163, 151184, 151185, 151190.
Carassius sp.
Cyprinus auratus Linnaeus, 1758: 322. Type locality: China; Japanese rivers.
References for Tajikistan: Carassius auratus gibelio — Rasulov and Karimov (2014: 40): Kairakkum reservoir. Carassius gibelio — Afanasyev et al. (2020: 369): Kairakkum reservoir, quite abundant object of commercial fishery.
Distribution in Tajikistan: slow flowing and stagnant waters of Amu Darya and Syr Darya drainages, possibly Zeravshan (localities 10, 29).
Specimens examined: IBIW_FS (n = 3) (Artaev et al., 2024), in 2003–2018, specimens were also caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve. FMNH 151164.
Comments: Invasive species. Most likely, crucian carp in Tajikistan belong to C. auratus (Linnaeus, 1758) because of massive fish introduction from the Far East during the 20th century. Occurrence of another species, C. gibelio (Bloch, 1782), is also possible as it was reported from the same riverine systems in Uzbekistan (Sheraliev and Peng, 2021).
Cyprinus carpio Linnaeus, 1758
Cyprinus carpio Linnaeus, 1758: 320. Type locality: Europe.
References for Tajikistan: Cyprinus carpio — Berg (1905: 48): Syr Darya; Berg (1949: 835): Amu Darya up to Panj, Zeravshan, Syr Darya; Shaposhnikova (1950: map): flat zone and lower part of foothill zone of Amu Darya basin; Rasulov and Karimov (2014: 39): Kairakkum reservoir; Afanasyev et al. (2020: 368): Syr Darya including Kairakkum reservoir. Cyprinus carpio carpio — Nikolskiy (1938: 148): widespread in flat parts of Tajikistan.
Distribution in Tajikistan: Kairakkum reservoir, lower reaches of Vakhsh River with oxbows of Tigrovaya Balka Reserve, and farm ponds in the flat parts of Tajikistan.
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Freyhof and Kottelat, 2008a).
Specimens examined: FMNH: 151149, in 2003–2018 specimens were caught (not preserved) in floodplain lakes and the Vakhsh River bed.
Comments: In addition to the native populations, it was probably introduced from other parts within its native range as an object of aquaculture.
Luciobarbus brachycephalus (Kessler, 1872)
Barbus brachycephalus Kessler, 1872: 52. Type locality: Syr Darya River, central Asia.
References for Tajikistan: Barbus brachycephalus — Berg (1905: 65): Syr Darya; Nikolskiy (1938: 112): Syr Darya and Amu Darya; Berg (1949: 705): Amu Darya up to Somoni (Faizabadkala); Shaposhnikova (1950: map): flat zone and lower part of foothill zone of Amu Darya basin; Rasulov and Karimov (2014: 39): Kairakkum reservoir.
Distribution in Tajikistan: Syr Darya including Kairakkum reservoir, Amu Darya with lower reaches of Vakhsh, possibly in Kafirnigan, and Kyzylsu Rivers.
Conservation status in Tajikistan: Vulnerable (Saidov, 2017); vulnerable (sensu IUCN; Freyhof and Kottelat, 2008b).
Specimens examined: In 2003–2018, specimens were caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Luciobarbus conocephalus (Kessler, 1872)
Barbus conocephalus Kessler, 1872: 50. Type locality: Zeravshan River, Uzbekistan.
References for Tajikistan: Barbus bulatmai conocephalus — Berg (1905: 73): Zeravshan, upstream Syr Darya. Barbus capito conocephalus — Nikolskiy (1938: 108): Syr Darya, Amu Darya (up to foothills), Kafirnigan); Berg (1949: 701): Amu Darya up to Somoni (Faizabadkala), Kafirnigan, Zeravshan, Syr Darya; Shaposhnikova (1950: map): (flat zone and lower part of foothill zone of Amu Darya basin); Rasulov and Karimov (2014: 39): Kairakkum reservoir. Barbus lacertoides — Kessler (1872: 51): Springs near Khujand. Luciobarbus capito — Afanasyev et al. (2020: 367): Syr Darya downstream Kairakkum reservoir.
Distribution in Tajikistan: Amu Darya in foothill zone, Syr Darya including Kairakkum reservoir, lower reaches of Vakhsh, Kafirnigan (locality 14).
Conservation status in Tajikistan: Vulnerable (Saidov, 2017); vulnerable (sensu IUCN; Freyhof and Kottelat, 2008c).
Specimens examined: IBIW_FS (n = 1) (Artaev et al., 2024). In 2003–2018, specimens were caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Schizopygopsis sewerzowi Herzenstein, 1891
Schizopygopsis sewerzowi Herzenstein, 1891: 196. Type locality: Lake Bulunkul and Karasu River, Amu Darya basin, Pamir mountains.
References for Tajikistan: Schizopygopsis stoliczkae — Berg (1905: 106; 1949: 730): upstream Amu Darya (Kara-Su, Alichur Rivers, Lakes Bulunkul, Karakul). Schizopygopsis sewerzowi — Berg (1905: 107), Shaposhnikova (1950: map): (upstream Amu Darya, inhabit together with Schizopygopsis stoliczkae). Schizopygopsis stoliczkai — Nikolskiy (1938: 131), Shaposhnikova (1950: map): mountain part of Amu Darya basin, Pamir. Schizopygopsis stoliczkai infraspecies sewerzowi Berg (1949: 731): Pamir part of Amu Darya basin.
Distribution in Tajikistan: Pamir region of Amu Darya basin (localities 40–44, 47–49).
Conservation status in Tajikistan: Not known; not known (sensu IUCN; Freyhof et al., 2022).
Specimens examined: IBIW_FS (n = 41) (Artaev et al., 2024). FMNH: 145623, 145625, 145626, 145628, 145629, 145631–33, 145635, 145640, 145643, 145646.
Comments: Nikolskiy (1938) suggested that the difference between main diagnostic characters (eye size and body height) of Schizopygopsis stoliczkai and Schizopygopsis sewerzowi is insufficient to classify them as a different species. Our genetic data confirm the validity of S. sewerzowi. In particular, samples from the Pamir region (GenBank acc. nos. PP993467–68) differ (p-distance = 1.3%) from samples of S. stoliczkai from its type basin, the Indus River (KY032326, 1118 bp), in cytochrome b sequence. In addition, Schizopygopsis sewerzowi is known to have up to four trophic ecomorphs in young Pamir lakes (e.g., Yashilkul) that are divergent in mouth types and feeding modes (Savvaitova et al., 1988; Komarova et al., 2021). It is still unknown whether sympatric ecomorphs are genetically differentiated or not.
Schizothorax eurystomus Kessler, 1872
Schizothorax eurystomus Kessler, 1872: 53. Type locality: Dznam near Samarkand, Uzbekistan.
References for Tajikistan: Schizothorax eurystomus — Afanasyev et al. (2020: 367): Syr Darya including Kairakkum reservoir. Schizothorax intermedius — Berg (1905: 79), Nikolskiy (1938: 123), Rasulov (2011: 248, 535): Syr Darya. Schizothorax intermedius forma typica — Berg (1949: 715): Syr Darya. Schizothorax intermedius morpha eurystomus — Berg (1949: 715): Syr Darya. Schizothorax intermedius morpha fedtschenkoi — Berg (1949: 715): Syr Darya. Schizothorax intermedius var. eurystomus — Berg (1905: 81): Syr Darya.
Distribution in Tajikistan: Syr Darya basin (localities 1, 3).
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Karimov, 2020a).
Specimens examined: IBIW_FS (n = 15) (Artaev et al., 2024). FMNH: 145607, 145610, 145612, 145614, 145616, 145622, 145641, 145644, 145648, 145651, 145653, 151135, 151141, 151186, 151195, 151198, 151203, 151206.
Comments: Schizothorax from the Syr Darya basin form one mitochondrial clade; this is also confirmed for neighboring Uzbekistan (Sheraliev and Peng, 2021). For the Syr Darya basin, 2 taxonomic units at the rank of subspecies were described: S. intermedius eurycephalus Berg, 1932, from Lake Sary-Chilek and S. intermedius angreni Turdakov, 1968, from the Angren River. The species name applied to this clade is used according to Sheraliev and Peng (2021), however, further taxonomic studies are needed.
Schizothorax fedtschenkoi Kessler, 1872
Schizothorax fedtschenkoi Kessler, 1872: 55. Type locality: Zeravshan River, Uzbekistan.
References for Tajikistan: Schizothorax fedtschenkoi — Berg (1905: 97): Zeravshan. Schizothorax intermedius — Berg (1905: 79), Nikolskiy (1938: 123): Zeravshan. Rasulov (2011: 248, 535): Zeravshan. Schizothorax intermedius forma typica — Berg (1949: 715): Zeravshan. Schizothorax intermedius morpha eurystomus — Berg (1949: 715): Zeravshan. Schizothorax intermedius morpha fedtschenkoi — Berg (1949: 715): Zeravshan. Schizothorax intermedius var. eurystomus — Berg (1905: 81): Zeravshan. Schizothorax irregularis — Berg (1905: 82): rivers of Samarkand region.
Distribution in Tajikistan: Zeravshan basin (localities 6, 7).
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Karimov, 2020b).
Specimens examined: IBIW_FS (n = 10) (Artaev et al., 2024). FMNH: 145607, 145610, 145612, 145614, 145616, 145622, 145641, 145644, 145648, 145651, 145653, 151135, 151141, 151186, 151195, 151198, 151203, 151206.
Comments: All species from the Zeravshan basin form one mitochondrial clade; this is also confirmed for neighboring Uzbekistan (Sheraliev and Peng, 2021). Initially, Kessler (1872) described four species from the Zeravshan basin: S. affinis, S. fedtschenkoi, S. (Oreinus) eurystomus and S. (Oreinus) minutus. The species name applied to this clade is used according to Sheraliev and Peng (2021), however, further taxonomic studies are needed.
Schizothorax sp.
References for Tajikistan: Schizothorax intermedius — Berg (1905: 79), Nikolskiy (1938: 123): Amu Darya; Shaposhnikova (1950: map): mountainous part of Amu Darya basin; Rasulov (2011: 248, 535): upstream Amu Darya, Vakhsh, Kafirnigan, Kyzylsu, Panj, Pamir lakes. Schizothorax intermedius forma typica — Berg (1949: 715): upper Amu Darya. Schizothorax intermedius morpha eurystomus — Berg (1949: 715): upper Amu Darya. Schizothorax intermedius morpha fedtschenkoi — Berg (1949: 715): upper Amu Darya; Shaposhnikova (1950: map): mountainous part of Amu Darya basin. Schizothorax intermedius var. eurystomus — Berg (1905: 81): Amu Darya. Schizothorax irregularis — Berg (1905: 82): upstream Amu Darya. Schizothorax microcephalus — Day (1877: 787): Panja (Panjah), waters going to the Oxus, India, elevation 9000 feet. Schizothorax regeli — Berg (1905: 98): upper Amu Darya.
Distribution in Tajikistan: Amu Darya basin (localities 10–13, 17, 19, 20, 23, 26, 27, 30, 32, 33, 34, 37, 40, 41, 45).
Conservation status in Tajikistan: Not known; not known (sensu IUCN).
Specimens examined: IBIW_FS (n = 47) (Artaev et al., 2024). FMNH: 145607, 145610, 145612, 145614, 145616, 145622, 145641, 145644, 145648, 145651, 145653, 151135, 151141, 151186, 151195, 151198, 151203, 151206.
Comments: Schizothorax from the Amu Darya basin form one mitochondrial clade; this is also confirmed for neighboring Uzbekistan (Sheraliev and Peng, 2021). Four taxa have been described from the Amu Darya basin, now assigned to the genus Schizothorax: Racoma gobioides McClelland, 1842, Schizothorax microcephalus Day, 1877, Schizothorax regelii Herzenstein, 1889, and Schizothorax intermedius kessleri Turdakov, 1968. Further taxonomic studies are needed to confirm identity of species within this clade.
Family Esocidae
Esox lucius Linnaeus, 1758
Esox lucius Linnaeus, 1758: 314. Type locality: Europe.
References for Tajikistan: Esox lucius — Berg (1905: 215): lakes in Syr Darya drainage; Nikolskiy (1938: 178): Syr Darya drainage; Berg (1949: 450): Syr Darya; Rasulov and Karimov (2014: 40): Kairakkum reservoir; Afanasyev et al. (2020: 369): Syr Darya including Kairakkum reservoir and floodplain lakes.
Distribution in Tajikistan: Syr Darya including Kairakkum reservoir.
Specimens examined: In 2003–2018, specimens were caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Conservation status in Tajikistan: Endangered (Saidov, 2017); least concern (sensu IUCN; NatureServe, 2018).
Family Gobiidae
Rhinogobius sp.
References for Tajikistan: Cobitus cheni — Zharov (1969): lower Vakhsh. Cobius cliffordpopei — Zharov (1969): lower Vakhsh. Cobitus cliffordpopei — Akhrorov (2006: 34): Tajikistan. Rhinogobius similis lindbergi — Akhrorov (2006: 34): Tajikistan. Rhinogobius similis — Rasulov (2011: 70, 540): Syr Darya, Vakhsh, Kafirnigan, Kairakkum reservoir.
Distribution in Tajikistan: Low-lying flat parts of Tajikistan (localities 4, 10, 17).
Conservation status in Tajikistan: Not known; not known (sensu IUCN).
Specimens examined: IBIW_FS (n = 3) (Artaev et al., 2024). In 2003–2018, specimens caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Comments: Invasive species. See Discussion.
Family Gobionidae
Abbottina rivularis (Basilewsky, 1855)
Gobio rivularis Basilewsky, 1855: 231. Type locality: Lakes and rivers, northern China.
References for Tajikistan: Pseudogobio rivularis — Rasulov (2011: 239, 535): Syr Darya, Amu Darya, lower Vakhsh, Kafirnigan, Kairakkum reservoir.
Distribution in Tajikistan: Syr Darya, Amu Darya, lower Vakhsh, Kafirnigan, Kairakkum reservoir (localities 8, 10).
Specimens examined: IBIW_FS (n = 2) (Artaev et al., 2024).
Comments: Invasive species.
Gobio lepidolaemus Kessler, 1872
Gobio fluviatilis var. lepidolaemus Kessler, 1872: 59. Type locality: Zeravshan River basin, Uzbekistan; Syr Darya River at Khujand (Leninabad), Tajikistan.
References for Tajikistan: Gobio gobio lepidolaemus — Berg (1905: 126), Nikolskiy (1938: 101), Berg (1949: 648): Amu Darya, Syr Darya; Shaposhnikova (1950: map): foothill zone of Amu Darya basin.
Distribution in Tajikistan: Syr Darya drainage, possibly Amu Darya (locality 2).
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Mamilov and Karimov, 2020b).
Specimens examined: Collection material: IBIW_FS (n = 3) (Artaev et al., 2024). FMNH: 151208, 151214.
Comments: This species is very closely related to G. sibiricus (COI K2P distance 0.72%; Sheraliev and Peng, 2021). Nikolskiy (1938) also pointed out the lack of a clear boundary between gudgeons of Central Asia: “the Turkestan gudgeon is an extreme link in the range of geographical races, starting in the north with the typical Gobio gobio gobio and through Gobio gobio sibiricus, going to Gobio gobio lepidolaemus.” Gobio species of the region require more detailed taxonomic studies.
Gobio nigrescens (Keyserling, 1861)
Bungia nigrescens Keyserling, 1861: 19. Type locality: Harirud River at Herat, Afghanistan.
References for Tajikistan: Gobio gobio lepidolaemus — Berg (1905: 126), Nikolskiy (1938: 99), Berg (1949: 648): Zeravshan.
Distribution in Tajikistan: Zeravshan drainage (locality 6).
Conservation status in Tajikistan: Not known; not known (sensu IUCN).
Specimens examined: IBIW_FS (n = 1) (Artaev et al., 2024). FMNH: 151197, 151202.
Gobio sibiricus Nikolskiy, 1936
Gobio gobio sibiricus Nikolskiy, 1936: 470. Type locality: Upper parts of Yenisei and Ob River basins, western Siberia, Russia; Nura River, Kazakhstan.
References for Tajikistan: Gobio gobio lepidolaemus — Berg (1905: 126), Nikolskiy (1938: 101), Berg (1949: 648): Amu Darya, Syr Darya; Shaposhnikova (1950: map): foothill zone of Amu Darya basin.
Distribution in Tajikistan: Amu Darya drainages (localities 14, 15).
Conservation status in Tajikistan: Not known; least concern (Bogutskaya, 2020).
Specimens examined: IBIW_FS (n = 2) (Artaev et al., 2024). FMNH: 151146, 151169.
Comments: Based on DNA barcoding, we identified this species in the lower reaches of the Vakhsh in 2017. Also noted for the Amu Darya basin (Surkhandarya River) in Uzbekistan (Sheraliev and Peng, 2021).
Pseudorasbora parva (Temminck and Schlegel, 1846)
Leuciscus parvus Temminck and Schlegel, 1846: 215. Type locality: Japan.
References for Tajikistan: Pseudorasbora parva — Akhrorov (2006: 34): Tajikistan; Afanasyev et al. (2020: 370): Kairakkum reservoir. Pseudorasbora parva parvula — Zharov (1969): lower Vakhsh.
Distribution in Tajikistan: Widespread in the lowland parts of Tajikistan (localities 4, 7, 10, 14, 19, 28, 29, 32).
Specimens examined: IBIW_FS (n = 8) (Artaev et al., 2024). FMNH: 151143, 151150, 151155, 151180. In 2003–2018, specimens were caught (not preserved) in the floodplain lakes of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Comments: An invasive species spread in Tajikistan due to the acclimatization of Far Eastern fish species. First recorded from the lakes in the lower reaches of the Vakhsh basin in 1965–1969 (Zharov, 1969).
Family Leuciscidae
Abramis brama (Linnaeus, 1758)
Cyprinus brama Linnaeus, 1758: 326. Type locality: European lakes.
References for Tajikistan: Abramis brama — Nikolskiy (1938: 139): Syr Darya; Afanasyev et al. (2020: 367): Syr Darya and Kairakkum reservoir. Abramis brama orientalis — Berg (1949: 775): Syr Darya (in lakes); Rasulov and Karimov (2014: 39): Kairakkum reservoir.
Distribution in Tajikistan: Recorded in Kairakkum reservoir and lower reaches of the Vakhsh River.
Conservation status in Tajikistan: Vulnerable (Saidov, 2017); least concern (sensu IUCN; Freyhof and Kottelat, 2008d).
Specimens examined: In 2003–2018, specimens were caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Alburnoides holciki Coad and Bogutskaya, 2012
Alburnoides holciki Coad and Bogutskaya, 2012: 44. Type locality: Hari River at Herat, Afghanistan.
References for Tajikistan: Alburnus bipunctatus — Berg (1905: 162): Amu Darya basin. Alburnoides bipunctatus eichwaldi — Nikolskiy (1938: 134), Berg (1949: 760): tributaries of Amu Darya, Zeravshan; Shaposhnikova (1950: map): foothill zone of Amu Darya basin.
Distribution in Tajikistan: Widely spread in the plains and foothill zones of rivers of Amu Darya and Zeravshan basins (localities 6, 8, 9, 10, 14–16, 17, 19, 20, 25, 28, 31).
Conservation status in Tajikistan: Not known; not known (sensu IUCN).
Specimens examined: IBIW_FS (n = 39) (Artaev et al., 2024). FMNH: 151131, 151196, 151122, 151128, 151136, 151137, 151147, 151151, 151160, 151167, 151175–78, 151189, 151200. In 2003–2018, specimens were caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Comments: Analysis of genetic and morphological data showed that this previously unknown species from Tajikistan rivers belongs to the recently described species Alburnoides holciki (Levin et al., 2019a).
Alburnus taeniatus Kessler, 1874
Alburnus taeniatus Kessler, 1874: 26. Type locality: Syr Daria River, Turkestan (Kazakhstan).
References for Tajikistan: Alburnoides taeniatus — Afanasyev et al. (2020: 367): Syr Darya including Kairakkum reservoir. Alburnus taeniatus — Berg (1905: 162): Amu Darya basin. Alburnoides taeniatus — Nikolskiy (1938: 137), Berg (1949: 761): Syr Darya, flat part of Amu Darya; Shaposhnikova (1950: map): flat part and foothill zone of Amu Darya basin.
Distribution in Tajikistan: Amu Darya, lower reach of Vakhsh River, Zeravshan, Syr Darya, and Kairakkum reservoir (5, 8, 19, 29).
Conservation status in Tajikistan: Not known; data deficient (sensu IUCN; Karimov, 2020c).
Specimens examined: IBIW_FS (n = 14) (Artaev et al., 2024). FMNH: 151166, 151209. In 2003–2018, specimens were caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Comments: Based on large morphological differences (Jouladeh-Roudbar et al., 2016) and molecular data (Schönhuth et al., 2018; Jouladeh-Roudbar et al., 2020), this species is now considered to belong to the genus Alburnus.
Alburnus cf. chalcoides (Güldenstädt, 1772)
Alburnus chalcoides aralensis Berg, 1923: 272. Type locality: Vozrozhdenie Island, Aral Sea.
References for Tajikistan: Alburnus chalcoides — Afanasyev et al. (2020: 367): Syr Darya including Kairakkum reservoir.
Distribution in Tajikistan: Syr Darya, lower reach of Vakhsh River, and possibly Amu Darya. Possible changes of range are considered in Discussion (localities 4, 15).
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Freyhof and Kottelat, 2008e).
Specimens examined: IBIW_FS (n = 6). FMNH: 151138, 151142, 151158.
Comments: Previously this species was found in lower reaches of Amu Darya (Shaposhnikova, 1950), Syr Darya, and Zeravshan up to Samarkand (Berg, 1949). Nikolskiy (1938) did not include it in the list of species for Tajikistan. Further study is needed to clarify the taxonomic status of this species.
Aspiolucius esocinus (Kessler, 1874)
Aspius esocinus Kessler, 1874: 28. Type locality: Syr Darya and Amu Darya, Turkestan.
References for Tajikistan: Aspius esocinus — Berg (1905: 159): Amu Darya, Syr Darya. Aspiolucius esocinus — Nikolskiy (1938: 93): Syr Darya, flat part of Amu Darya; Berg (1949: 602): Amu Darya up to Kafirnigan, Syr Darya; Shaposhnikova (1950: map): flat zone and lower part of foothill zone of Amu Darya basin; Afanasyev et al. (2020: 366): Syr Darya outside Kairakkum Reservoir.
Distribution in Tajikistan: Syr Darya River bed outside the Kairakkum reservoir, Amu Darya, lower reaches of Vakhsh. Possibly found in other large rivers in the flat parts of the Amu Darya basin, such as the Panj, Kafirnigan, and Kyzyl-Su.
Conservation status in Tajikistan: Conservation status in Tajikistan: Critically endangered (Saidov, 2017); endangered (sensu IUCN: Karimov, 2020d).
Specimens examined: In 2003–2018, specimens were caught (not preserved) in the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Ballerus sapa (Pallas, 1814)
Cyprinus sapa Pallas, 1814: 328. Type locality: Volga River and tributaries.
References for Tajikistan: Ballerus sapa — Afanasyev et al. (2020: 368): Syr Darya including Kairakkum reservoir. Ballerus sapa bergi — Nikolskiy (1938: 141): Syr Darya. Abramis sapa bergi natio aralensis — Berg (1949: 784): Syr Darya. Abramis sapa aralensis — Rasulov and Karimov (2014: 39): Kairakkum reservoir. Abramis sapa ferghanensis — Akhrorov (2006: 33): Tajikistan.
Distribution in Tajikistan: Syr Darya including Kairakkum reservoir, lower reaches of Vakhsh river, and flat parts of the Amu Darya.
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Freyhof and Kottelat, 2008f).
Specimens examined: In 2003–2018, specimens were caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Capoetobrama kuschakewitschi (Kessler, 1872)
Acanthobrama kuschakewitschi Kessler, 1872: 64. Type locality: Khujand, Tajikistan.
References for Tajikistan: Acanthobrama kuschakewitschi — Berg (1905: 177): Syr Darya. Capoetobrama kuschakewitschi — Nikolskiy (1938: 142): Amu Darya up to Somoni (Faizabadkala), Kafirnigan up to Shartuz, Syr Darya; Berg (1949: 800): Amu Darya, Syr Darya; Shaposhnikova (1950: map): flat zone and lower part of foothill zone of Amu Darya basin; Rasulov and Karimov (2014: 39): Kairakkum reservoir; Afanasyev et al. (2020: 368): Syr Darya including Kairakkum reservoir.
Distribution in Tajikistan: Syr Darya, Amu Darya, Panj, Kafirnigan, Kairakkum reservoir, Vakhsh (localities 9, 15).
Conservation status in Tajikistan: Endangered (Saidov, 2017); endangered (sensu IUCN; Mamilov and Karimov, 2020c).
Specimens examined: IBIW_FS (n = 4) (Artaev et al., 2024). In 2003–2018, specimens caught (not preserved) in the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Leuciscus aspius (Linnaeus, 1758)
Cyprinus aspius Linnaeus, 1758: 25. Type locality: Swedish lakes.
References for Tajikistan: Aspius aspius erythrostomus — Berg (1905: 155): Syr Darya. Aspius aspius taeniatus natio ibiloides — Berg (1912: 155): Syr Darya; Berg (1949: 609): Syr Darya, Amu Darya up to Kafirnigan; Shaposhnikova (1950: map): flat zone and lower part of foothill zone of Amu Darya basin; Rasulov and Karimov (2014: 40): Kairakkum reservoir. Aspius aspius iblioides — Nikolskiy (1938: 97): Amu Darya up to Kafirnigan mouth, Syr Darya. Leuciscus aspius — Afanasyev et al. (2020: 366): Syr Darya including Kairakkum reservoir.
Distribution in Tajikistan: Syr Darya, flat part of Amu Darya, Kairakkum reservoir, and lower reaches of Vakhsh river.
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Freyhof and Kottelat, 2018).
Specimens examined: In 2003–2018 specimens were caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Leuciscus lehmanni Brandt, 1852
Leuciscus lehmanni Brandt, 1852: 339. Type locality: Samarkand, Uzbekistan.
References for Tajikistan: Squalius lehmanni — Berg (1905: 133): Zeravshan. Leuciscus lehmanni lehmanni — Nikolskiy (1938: 87): Zeravshan. Leuciscus lehmanni — Berg (1949: 549): Zeravshan; Shaposhnikova (1950: map): foothill zone of Amu Darya basin.
Distribution in Tajikistan: Likely in Zeravshan, and possibly Amu Darya.
Conservation status in Tajikistan: Not known; least concern (Karimov and Mamilov, 2020).
Specimens examined: None.
Leuciscus idus (Linnaeus, 1758)
Squalius oxianus Kessler, 1877: 124. Type locality: Lower part of Amu Darya, and Kunja-Urgentsch in delta of Amu Darya, Uzbekistan.
References for Tajikistan: Leuciscus idus — Afanasyev et al. (2020: 366): Syr Darya including Kairakkum reservoir. Leuciscus idus oxianus — Rasulov (2011: 535, 524): Amu Darya, Syr Darya.
Distribution in Tajikistan: A few specimens have been recorded in Syr Darya and Kairakkum reservoir (Afanasyev et al., 2020).
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Freyhof and Kottelat, 2008g).
Specimens examined: None.
Pelecus cultratus (Linnaeus, 1758)
Cyprinus cultratus Linnaeus, 1758: 326. Type locality: Helgean River (Sweden).
References for Tajikistan: Pelecus cultratus — Berg (1905: 179): Syr Darya; Nikolskiy (1938: 145): Amu Darya up to Panj, Kafirnigan, Syr Darya; Berg (1949: 812): Syr Darya, Amu Darya up to Panj confluence; Shaposhnikova (1950: map): flat zone and lower part of foothill zone of Amu Darya basin; Rasulov and Karimov (2014: 39): Kairakkum reservoir; Afanasyev et al. (2020: 368) Syr Darya including Kairakkum reservoir.
Distribution in Tajikistan: Syr Darya and Kairakkum reservoir, Amu Darya, including lower reaches of Vakhsh with oxbows of Tigrovaya Balka reserve. Possibly in Kafirnigan (Rasulov, 2011).
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Freyhof and Kottelat, 2008h).
Specimens examined: In 2003–2018, specimens were caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Petroleuciscus squaliusculus (Kessler, 1872)
Squalius squaliusculus Kessler, 1872: 61 Type locality: Syr Darya at Khujand.
References for Tajikistan: Squalius lehmanni squaliusculus — Berg (1905: 134): springs around Khujand — near Nau and Ak-Tube (possibly currently it is Nov and Okteppa). Leuciscus squaliusculus — Berg (1912: 150), Nikolskiy (1938: 88), Berg (1949: 564): springs around Khujand — near Nau and Ak-Tube (possibly currently it is Nov and Okteppa). Leuciscus baikalensis tipica — Rasulov (2011: 152, 537): Syr Darya.
Distribution in Tajikistan: This species is said to inhabit springs and tributaries of Syr Darya basin near Khujand, however none were encountered during our fieldwork, though, despite rigorous search, not all springs were located. Further investigation is needed.
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Karimov, 2020e).
Specimens examined: None.
Rutilus lacustris (Pallas, 1814)
Cyprinus lacustris Pallas, 1814: 314. Type locality: Siberia, Russia.
References for Tajikistan: Leuciscus rutilus — Berg (1905: 128): Syr Darya. Rutilus rutilus — Afanasyev et al. (2020: 366): Syr Darya including Kairakkum reservoir. Rutilus rutilus aralensis — Nikolskiy (1938: 80), Berg (1949: 507): Syr Darya; Rasulov and Karimov (2014: 39): Kairakkum reservoir. Rutilus rutilus bucharensis — Nikolskiy (1938: 82): Amu Darya up to Aiwanj. Rutilus rutilus aralensis natio bucharensis — Berg (1949: 512): Amu Darya up to Vakhsh mouth; Shaposhnikova (1950: map): foothill zone of Amu Darya basin. Rutilus rutilus aralensis morpha phragmiteti — Akhrorov (2006: 33): Tajikistan. A molecular study on Rutilus rutilus sensu lato showed two mitochondrial lineages — European (Rutilus rutilus) and Asian (Rutilus lacustris), with R. lacustris occurring in the Aral Sea basin (Levin et al., 2017).
Distribution in Tajikistan: Amu Darya, lower reaches of the Vakhsh with oxbows of Tigrovaya Balka reserve, Syr Darya including Kairakkum reservoir (locality 4).
Conservation status in Tajikistan: Not known; not known (sensu IUCN).
Specimens examined: IBIW_FS (n = 7) (Artaev et al., 2024). FMNH: 151211. In 2003–2018, specimens caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Scardinius erythrophthalmus (Linnaeus, 1758)
Cyprinus erythrophthalmus Linnaeus, 1758: 324. Type locality: northern Europe.
References for Tajikistan: Scardinius erythrophthalmus — Berg (1905: 130), Nikolskiy (1938: 90), Berg (1949: 595): Syr Darya; Rasulov and Karimov (2014: 40): Kairakkum reservoir; Afanasyev et al. (2020: 366): Syr Darya including Kairakkum reservoir. Scardinius erythrophlhalmus — Akhorov (2006: 33): Tajikistan. Scardinius erythzophthalmus — Rasulov (2011: 231, 535): Syr Darya, Kairakkum reservoir.
Distribution in Tajikistan: Syr Darya including Kairakkum reservoir.
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Freyhof and Kottelat, 2008i).
Specimens examined: Recorded in fishermen's catches in Kairakkum Reservoir by authors.
Family Nemacheilidae
Dzihunia amudarjensis (Rass, 1929)
Nemachilus amudarjensis Rass, 1929: 253. Type locality: Amu Darya at Termez, Uzbekistan.
References for Tajikistan: Nemachilus amudariensis — Nikolskiy (1938: 162), Berg (1949: 882): Amu Darya up to Aiwanj.
Distribution in Tajikistan: Amu Darya, possibly in Zeravshan and Syr Darya drainages.
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Karimov, 2020f).
Specimens examined: IBIW_FS (n = 20) (Artaev et al., 2024). FMNH 151192.
Comments: The systematics of this genus requires additional research using integrative taxonomic methods.
Oxynoemacheilus oxianus (Kessler, 1877)
Nemacheilus brandtii var. oxiana Kessler, 1877: 177. Type locality: Amu Darya, Uzbekistan.
References for Tajikistan: Nemacheilus flavus — Berg, 1905: 196 Syr Darya. Nemacheilus oxianus — Nikolskiy (1938: 164), Berg (1946: 880): flat part of Amu Darya, Syr Darya, Zeravshan; Shaposhnikova (1950: map): flat zone and lower part of foothill zone of Amu Darya basin; Afanasyev et al. (2020: 368): Syr Darya River bed outside of Kairakkum reservoir.
Distribution in Tajikistan: Flat part of Amu Darya, possibly Syr Darya and Zeravshan.
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Karimov, 2020g).
Specimens examined: None.
Paracobitis longicauda (Kessler, 1872)
Cobitis longicauda Kessler, 1872: 65. Type locality: Amu-Darya River (Zeravshan river drainage), Uzbekistan.
References for Tajikistan: Nemachilus malapterurus longicauda — Berg (1905: 192): Zeravshan, Amu Darya; Nikolskiy (1938: 153): Amu Darya, Vakhsh, Surhan, and Dyshambinka (Varzob); Berg (1949: 886): Amu Darya, Vakhsh, Surhan, Kafirnigan, Dyshambinka (Varzob), Zeravshan; Shaposhnikova (1950: map): foothill zone of Amu Darya basin.
Distribution in Tajikistan: Widespread in Amu Darya drainage (localities 8–10, 14, 15, 17, 19–21, 25, 28–33).
Conservation status in Tajikistan: Not known; not known (sensu IUCN).
Specimens examined: IBIW_FS (n = 37) (Artaev et al., 2024). FMNH: 145654, 145657, 151132, 151127, 151140, 151153, 151162, 151168, 151183, 151188, 151194.
Iskandaria pardalis (Turdakov, 1941)
Nemachilus pardalis, Turdakov, 1941: 219. Type locality: Dyushambinka (Varzob) River at Dushanbe (Stalinabad), Tajikistan.
References for Tajikistan: Nemachilus pardalis — Berg (1949: 881): Dyshambinka (Varzob); Shaposhnikova (1950: map): foothill zone of Amu Darya basin.
Distribution in Tajikistan: Amu Darya drainage.
Conservation status in Tajikistan: Not known; least concern (Karimov, 2020h).
Specimens examined: None.
Comments: Molecular genetic studies have cast doubt on the validity of this genus (Sheraliev and Kayumova, 2022; our data), suggesting that species belong to the genus Dzihunia. However, until nomenclatural and taxonomic actions are carried out, we propose to leave the species in the genus Iskandaria.
Iskandaria kuschakewitschi (Herzenstein, 1890)
Nemacheilus kuschakewitschi Herzenstein, 1890: 139. Type locality: Margelan and Andizhan, Syr Darya basin, Uzbekistan.
References for Tajikistan: Nemacheilus kuschakewitschi — Berg (1905: 193), Nikolskiy (1938: 160), Berg (1949: 881): Syr Darya; Afanasyev et al. (2020: 368): Syr Darya River bed outside of Kairakkum reservoir.
Distribution in Tajikistan: Syr Darya drainage.
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Karimov, 2020i).
Specimens examined: FMNH: 145608, 145613.
Comments: Molecular genetic studies have cast doubt on the validity of the genus (Sheraliev and Kayumova, 2022; our data), suggesting that species belong to the genus Dzihunia. However, until nomenclatural and taxonomic actions are carried out, we propose to leave the species in the genus Iskandaria.
Triplophysa cf. daryoae Sheraliev et al., 2022
Triplophysa daryoae Sheraliev et al., 2022: 51. Type locality: Sokh River, near Limbur village, an exclave of Uzbekistan surrounded by Kyrgyzstan, Syr Darya basin.
References for Tajikistan: None.
Distribution in Tajikistan: Syr Darya basin.
Conservation status in Tajikistan: Not known; not known (sensu IUCN).
Specimens examined: IBIW_FS (n = 3). FMNH: 151204, 151205, 145659, 151123, 151126, 151130, 151159, 151170, 151181, 151187, 151193, 151212, 151213.
Comments: Specimens from Dekhmai spring (locality 3 on fig. 1; photo on fig. 5E; GenBank acc. nos. PP990748–49) have 99.4% similarity (COI, our data) to Triplophysa daryoae from the type locality (Sokh River). Perhaps the species is widespread in the Syr Darya basin and not only in the Sokh basin.
Triplophysa dorsalis (Kessler, 1872)
Cobitis dorsalis Kessler, 1872: 67. Type locality: Yany-Kurgan, Syr Darya.
References for Tajikistan: Nemachilus dorsalis — Nikolskiy (1938: 167): Syr Darya; Berg (1949: 859): foothill zone of Amu Darya, Syr Darya; Shaposhnikova (1950: map): foothill zone of Amu Darya basin. Triplophysa dorsalis — Afanasyev et al. (2020: 368): Syr Darya River bed outside of Kairakkum reservoir.
Distribution in Tajikistan: Syr Darya and Amu Darya drainage.
Conservation status in Tajikistan: Not known; least concern (sensu IUCN).
Specimens examined: None.
Triplophysa ferganaensis Sheraliev and Peng, 2021
Triplophysa ferganaensis Sheraliev and Peng, 2021: 3. Type locality: Shakhimardan stream in Yordon village, an exclave of Uzbekistan within Kyrgyzstan.
References for Tajikistan: None.
Distribution in Tajikistan: Syr Darya drainage, rivers flowing from the northern slope of Turkestan ridge (locality 1).
Conservation status in Tajikistan: Not known; not known (sensu IUCN).
Specimens examined: IBIW_FS (n = 4) (Artaev et al., 2024). FMNH: 151204, 151205, 145659, 151123, 151126, 151130, 151159, 151170, 151181, 151187, 151193, 151212, 151213.
Triplophysa kafirnigani (Turdakov, 1948)
Nemachilus dorsalis kafirnigani Turdakov, 1948: 58. Type locality: Kafirnigan River, tributary of Amu Darya, near Dushanbe (Stalinabad), Tajikistan.
References for Tajikistan: Triplophysa dorsalis — Berg (1949: 859): Kafirnigan.
Distribution in Tajikistan: Upstream Kafirnigan and Karatog rivers (localities 13, 27).
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Karimov, 2020j).
Specimens examined: None.
Triplophysa lacusnigri (Berg, 1928)
Nemachilus stoliczkai var. lacusnigri Berg, 1928: 25. Type locality: Karakul Lake and tributary, Pamir Plateau, Tajikistan.
References for Tajikistan: Nemachilus lacus nigri — Akhrorov (2006: 32): Tajikistan. Nemachilus lacus-nigri — Berg (1949: 865): Karakul Lake in Pamir. Nemachilus stoliczkai lacus nigri — Nikolskiy (1938: 159): Karakul Lake in Pamir. Triplophysa lacusnigri — Vasil'eva and Nazarov (2023): Suok spring, tributary of Bulunkul Lake.
Distribution in Tajikistan: Lake Karakul and tributaries (locality 52), possibly the basin of Lake Bulunkul (see discussion).
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Karimov, 2020k).
Specimens examined: IBIW_FS (n = 3) (Artaev et al., 2024). FMNH: 145637
Comments: Additional taxonomic studies are needed. See Discussion.
Triplophysa stolickai (Steindachner, 1866) sensu lato
Cobitis stolickai Steindachner, 1866: 793. Type locality: Streams in Tsumureri Lake system, Rupshu Province, western Tibet, elevation 15,550 feet.
References for Tajikistan: Nemacheilus stoliczkae — Berg (1905: 193): mountain rivers in Amu Darya, Syr Darya, Zeravshan basins, also in mountain lakes (Karakul, Bulunkul). Nemachilus stoliczkai — Akhrorov (2006: 32): Tajikistan. Nemachilus stoliczkai — Berg (1949: 862): Zeravshan, Upper Amu Darya; Nikolskiy (1938: 157): mountain part of Amu Darya, Syr Darya and Zeravshan basins, lakes Iskanderkul, Yashilkul; Shaposhnikova (1950: map) mountain part of Amu Darya basin. Nemacheilus tenuis — Day (1877: 796): Aktash (12600 feet) where waters of Ak-su pass to Oxus (=Amu Darya). Triplophysa stoliczkai — Afanasyev et al. (2020: 368): Syr Darya River bed outside the Kairakkum reservoir.
Distribution in Tajikistan: Mountain rivers and some lakes in the Amu Darya, Syr Darya, and Zeravshan basins (localities 5, 6, 41, 42, 45, 47–49).
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Daniels, 2022).
Specimens examined: IBIW_FS (n = 33) (Artaev et al., 2024). FMNH: 145638, 145617, 145619, 145620, 145624, 145634, 145636, 145639, 145642, 145645, 145647, 145649, 145650, 145652.
Comments: Additional taxonomic studies are needed to clarify species of this group. See Discussion.
Triplophysa strauchii (Kessler, 1874)
Diplophysa strauchii Kessler, 1874: 58 Type locality: Ili River and Lake Balkhash, Kazakhstan.
References for Tajikistan: None.
Distribution in Tajikistan: This species is confirmed for the first time in the Zeravshan basin (locality 6 on fig. 1; photo in fig. 5B) and in the Vakhsh River (locality 19 on fig. 1) within Tajikistan by this study. Also possible in the Syr Darya basin (Sheraliev and Kayumova, 2022).
Specimens examined: IBIW_FS (n = 4) (Artaev et al., 2024). FMNH:151139.
Comments: An invasive species (Kamilov, 1995; Kayumova, 2020; Mamilov and Karimov, 2020d), entered the Syr Darya basin as a result of introduction in the second half of the 20th century and has spread extensively in the Syr Darya basin up to the upper reaches (Sheraliev et al., 2020).
Triplophysa uranoscopus (Kessler, 1872)
Type species by original designation: Cobitis uranoscopus Kessler, 1872: 66. Type locality: Tajikistan: Khodjaduk [Khodzhauk], Upper Amu Darya; Zeravshan, apparently includes syntypes from Lake Iskanderkul.
References for Tajikistan: None.
Distribution in Tajikistan: This species is confirmed for the first time in the Zeravshan basin (locality 6 on fig.1).
Conservation status in Tajikistan: Not known; least concern (Bogutskaya, 2020).
Specimens examined: IBIW_FS (n = 1) (Artaev et al., 2024). FMNH: 151199, 151201.
Comments: The species was synonymized by Berg (1949) with Nemachilus stolitczkai and revalidated as Triplophysa uranoscopus by Kottelat (2012).
Family Odontobutidae
Micropercops swinhonis (Günther, 1873)
Eleotris swinhonis Günther, 1873: 242. Type locality: Shanghai, China.
References for Tajikistan: Hypseleotris swinhonis — Rasulov (2011: 515, 539): Syr Daria, Vakhsh, Kairakkum reservoir.
Distribution in Tajikistan: Syr Daria, Vakhsh, Kairakkum reservoir.
Specimens examined: None.
Comments: Invasive species, accidentally introduced together with commercially important fish species from the Far East.
Family Percidae
Sander lucioperca (Linnaeus, 1758)
Perca lucioperca Linnaeus, 1758: 289. Type locality: European lakes.
References for Tajikistan: Lucioperca lucioperca — Rasulov and Karimov (2014: 40): Kairakkum reservoir; Rasulov (2011: 539, 446): Amu Darya, Syr Darya, Kairakkum reservoir; Afanasyev et al. (2020: 365): Syr Darya and Kairakkum reservoir.
Distribution in Tajikistan: Kairakkum reservoir, possibly Amu Darya and Syr Darya.
Specimens examined: None.
Comments: Introduced into Kairakkum reservoir in 1957 from the Ural region (Rasulov, 2011: 446).
Family Poeciliidae
Gambusia holbrooki Girard, 1859
Gambusia holbrooki Girard, 1859: 62. Type locality: Palatka, eastern Florida and Charleston, South Carolina.
References for Tajikistan: Gambusia affinis — Afanasyev et al. (2020: 370): reclamation canals of the Kairakkum reservoir. Gambusia affinis holbrooki — Shaposhnikova (1950: map): foothill zone of Amu Darya basin; Akhrorov (2006: 33): Tajikistan; Rasulov (2011: 107): Syr Darya, Zeravshan, Vakhsh, Kafirnigan, lowland lakes.
Distribution in Tajikistan: Widespread in still waters of lowland Tajikistan (2, 4, 19, 29).
Specimens examined: IBIW_FS (n = 4) (Artaev et al., 2024). FMNH: 151125, 151134, 151148, 151179. In 2003–2018, specimens were caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Comments: Introduced species, observed in Tajikistan since 1936 (Rasulov, 2011).
Family Salmonidae
Salmo oxianus Kessler, 1874
Salmo oxianus Kessler, 1874: 35. Type locality: Darmut stream, tributary of Kizil-Su River, Upper Amu Darya basin, Afghanistan.
References for Tajikistan: Salmo trutta oxianus — Berg (1905: 42): Kafirnigan basin, upstream Surkhandarya; Nikolskiy (1938: 77), Berg (1948: 259): Mountainous part of Amu Darya basin. Salmo trutta axianus — Rasulov (2011: 477, 533): upstream Surkhan, Kafirnigan, Vakhsh. Salmo trutta aralensis morpha fario — Shaposhnikova (1950: map): Mountainous part of Amu Darya basin.
Distribution in Tajikistan: Mountain and foothill parts of Amu Darya basin (locality 35).
Conservation status in Tajikistan: Endangered, vulnerable; not known (sensu IUCN).
Specimens examined: IBIW_FS (n = 2) (Artaev et al., 2024). FMNH: 145621.
Comments: A residential form of migratory trout that formerly inhabited the Aral Sea and spawned mainly in the Amu Darya (Berg, 1949). Validity of this species was confirmed by a recent genomic study (Segherloo et al., 2021).
Salmo ischchan Kessler, 1877
Salmo ischchan Kessler, 1877: 65. Type locality: Sevan Lake, Armenia.
References for Tajikistan: Salmo ischchan issykkulgegarkuni — Akhrorov (2006: 32): Tajikistan. Salmo ischan issykkulgegarkuni — Rasulov (2011: 479, 533): Yashilkul lake.
Distribution in Tajikistan: Lake Yashilkul and adjacent rivers. Our data confirm the presence of the species in Yashilkul (2019), indicating naturalization (locality 44).
Specimens examined: IBIW_FS (n = 1) (Artaev et al., 2024).
Comments: Trout from Lake Sevan (Armenia) in 1930 were acclimatized in Issyk-Kul (Kyrgyzstan), and then in 1982 it was transported from lake Issyk-Kul to lake Yashilkul (Rasulov, 2011). Validity of species was confirmed in genomic study (Levin et al., 2022).
Family Siluridae
Silurus glanis Linnaeus, 1758
Silurus glanis Linnaeus, 1758: 304. Type locality: Orient, less frequently in European lakes.
References for Tajikistan: Silurus glanis — Berg (1905: 209): Syr Darya; Nikolskiy (1938: 171): Amu Darya up to Panj (Baumanabad), Kafirnigan up to Shartuz, Vakhsh, Syr Darya; Berg (1949: 906): Syr Darya, Zeravshan, Amu Darya basin — Vakhsh, Kafirnigan; Shaposhnikova (1950: map): flat zone and lower part of foothill zone of Amu Darya basin; Rasulov and Karimov (2014: 40): Kairakkum reservoir; Afanasyev et al. (2020: 368): Syr Darya including Kairakkum reservoir.
Distribution in Tajikistan: Syr Darya including Kairakkum reservoir, flat part of Amr Darya, and the lower reaches of Vakhsh River with oxbows in Tigrovaya Balka Reserve (locality 9).
Conservation status in Tajikistan: Not known; least concern (sensu IUCN; Freyhof and Kottelat, 2008j).
Specimens examined: IBIW_FS (n = 1) (Artaev et al., 2024). In 2003–2018, specimens were caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Family Sisoridae
Glyptosternon cf. akhtari Silas, 1952
Glyptosternum akhtari Silas in Hora and Silas, 1952: 11. Type locality: Bamian River, Oxus (Amu Darya) watershed, Afghanistan.
References for Tajikistan: Exostoma stoiczkae — Berg (1905: 212): upstream Amu Darya. Glyptosternum reticulatum — Nikolskiy (1938: 176), Berg (1949: 924): upstream Amu Darya; Shaposhnikova (1950: map): mountainous part of Amu Darya basin.
Distribution in Tajikistan: Amu Darya drainage: Shirkent, Poyonob, Taikutal, Varzob, Kafirnigan, Karatog, Gissar, and Vakhsh rivers (localities 11–13, 16, 17, 20, 22, 23, 26, 32).
Conservation status in Tajikistan: Not known; not known (sensu IUCN).
Specimens examined: IBIW_FS (n = 59) (Artaev et al., 2024). FMNH: 132971, 132972, 132973, 145609, 145611, 145615, 145618.
Comments: Apparently Glyptosternum reticulatum sensu lato includes many species; a recent study allowed revalidation of Glyptosternum oschanini from the Syr Darya basin (Thoni et al., 2017). The species from the Amu Darya basin, including its Tajikistan part (GenBank acc. nos. PP990750–51) have a large genetic distance using the COI mtDNA marker from a species from Syr Darya drainage (2.1%–2.3% p-distance) and might represent a separate species referring to Glyptosternum akhtari, or represent a new undescribed species.
Family Xenocyprididae
Ctenopharyngodon idella (Valenciennes, 1844)
Leuciscus idella Valenciennes in Cuvier and Valenciennes, 1844: 362. Type locality: China.
References for Tajikistan: Ctenopharyngodon idella — Rasulov and Karimov (2014: 40): Kairakkum reservoir.
Distribution in Tajikistan: Kairakkum reservoir, lower reaches of Vakhsh River with oxbows in Tigrovaya Balka Reserve, also, possibly, some other reservoirs and fishery ponds in the flat part of Tajikistan.
Specimens examined: In 2003–2018, specimens caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Comments: Object of aquaculture, forms sustainable populations.
Hemiculter leucisculus (Basilewsky, 1855)
Culter leucisculus Basilewsky, 1855: 238. Type locality: rivers flowing into Bay of Tschili, Beijing, China.
References for Tajikistan: Hemiculter leucisculus — Akhrorov (2006: 34): south of Tajikistan; Rasulov (2011: 99, 537): Amu Darya, lower Vakhsh, fish farm ponds. Hemiculter lucidus — Afanasyev et al. (2020: 365, 370): Kairakkum reservoir. Hemiculter eigenmanni —Rasulov (2011: 100, 537): Tajikistan.
Distribution in Tajikistan: Plains rivers of the country, fish farm ponds in Amu Darya basin, possibly more widespread (localities 10, 14, 29).
Specimens examined: IBIW_FS (n = 4) (Artaev et al., 2024). FMNH: 151165, 151144, 151152. In 2003–2018, specimens caught (not preserved) in the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Comments: Invasive species, accidentally introduced together with commercially important fish species from the Far East. For more information on the taxonomy of this species see Discussion.
Hypophthalmichthys molitrix (Valenciennes, 1844)
Leuciscus molitrix Valenciennes in Cuvier and Valenciennes, 1844: 360. Type locality: China.
References for Tajikistan: Hypophthalmichthys molitrix — Rasulov and Karimov (2014: 40): Kairakkum reservoir; Rasulov (2011: 455): Kairakkum and Nurek reservoirs, fish farm ponds; Afanasyev et al. (2020: 369): Kairakkum reservoir.
Distribution in Tajikistan: Kairakkum and possibly Nurek reservoirs (Rasulov, 2011), lower reaches of Vakhsh river with oxbows of Tigrovaya Balka Reserve, also, possibly, some other reservoirs and fishery ponds in the flat parts of Tajikistan.
Specimens examined: In 2003–2018, specimens were caught (not preserved) in the floodplain lakes and the riverbed of the lower reaches of the Vakhsh River in the Tigrovaya Balka Nature Reserve.
Comments: Object of aquaculture, forms sustainable populations.
Hypophthalmichthys nobilis (Richardson, 1845)
Leuciscus nobilis Richardson, 1845: 140. Type locality: Canton, China.
References for Tajikistan: Aristichthys nobilis — Rasulov and Karimov (2014: 40): Kairakkum reservoir; Rasulov (2011: 455): fish farm ponds, Kairakkum and Nurek reservoir; Afanasyev et al. (2020 : 369): Kairakkum reservoir.
Distribution in Tajikistan: Fish farm ponds, Kairakkum and possibly Nurek reservoirs (Rasulov, 2011).
Specimens examined: None.
Comments: Object of aquaculture.
EXTINCT, DOUBTFUL, AND ERRONEOUSLY REPORTED SPECIES IN TAJIKISTAN
The following are species previously reported from Tajikistan or observed near the borders, whose current presence we consider doubtful. They include: (1) likely extinct species; (2) inhabitants of neighboring regions, but having no reliable facts of observations in Tajikistan, sometimes previously reported in lists as possibly inhabiting; (3) aquaculture objects and invasive species not naturalized in natural water bodies; and (4) misreported species for Tajikistan.
Likely Extinct Species
Acipenser nudiventris Lovetsky, 1828 (Acipenseridae)
Acipenser nudiventris Lovetsky, 1828: 78. Type locality: Aral Sea, Russia.
References for Tajikistan: Acipenser nudiventris — Berg (1905: 9): Syr Darya, possible Amu Darya; Nikolskiy (1938: 57) Amu Darya up to Panj (Baumanabad), Syr Darya up to Khujand; (Berg, 1948: 67) Amu Darya up to Panj (Kirovabad) on Panj River; Shaposhnikova (1950: map): flat zone and lower part of foothill zone of Amu Darya basin; Habilova (2012): Kairakkum Reservoir.
Comments: The last confident case of sampling A. nudiventris in Tajikistan was in Kairakkum Reservoir in 1958 (Habilova, 2012; Saidov, 2017). This species was mostly extirpated by the middle of the 20th century.
Pseudoscaphirhynchus fedtschenkoi (Kessler, 1872) (Acipenseridae)
Scaphirhynchus fedtschenkoi Kessler, 1872: 70. Type locality: Syr Darya near Chinaz, Kazakhstan.
References for Tajikistan: Pseudoscaphirhynchus fedtschenkoi — Berg (1905: 35), Nikolskiy (1938: 74), Berg (1949: 108): Syr Darya. Pseudoscaphirhynchus fedtschenroi — Akhrorov (2006: 32): Tajikistan.
Comments: Endemic of Syr Darya basin. According to Afanasyev et al. (2020) some local fishermen's notes have been made about recent findings in the Syr Darya River outside Kairakkum reservoir, but lack confirmation. Over the past 30 years from Tajikistan there has been no reliable information about this species. This is possibly an extinct species within Tajikistan.
Species That Inhabit Waters Near Tajikistan and May Be Found in the Country
Alburnus oblongus (Bulgakov, 1923) (Leuciscidae)
Alburnoides oblongus Bulgakov, 1923: 227. Type locality: Chirchik River near Tashkent, Uzbekistan.
References for Tajikistan: Alburnoides oblongus — Akhrorov (2006: 33): Tajikistan. Alburnoides ablongus — Rasulov (2014: 75, 537): Syr Darya.
Comments: Genetic study shows that this species belongs to the genus Alburnus (Matveyev et al., 2017). According to Nikolskiy (1938), species may be within the Syr Darya in Tajikistan, because the typical locality, Chirchik River near Tashkent, is not far from the borders of Tajikistan. However, this species has not yet been reported, despite multiple surveys in the region.
Cottus jaxartensis (Berg, 1916) (Cottidae)
Cottus gobio jaxartensis Berg, 1916: 437. Type locality: Syr Daria, Ugam River, tributary of Chirchik River, Syr Darya basin, Uzbekistan.
References for Tajikistan: Cottus gobio jaxartensis — Nikolskiy (1938: 179): probably in northern Tajikistan. Cottus nasalis — Berg (1933: 701; 1949: 1151), Nikolskiy (1938: 180): Turkestan, possibly Fergana, Syr Darya basin.
Comments: Based on morphological characters, Cottus nasalis was synonymized with Cottus jaxartensis (Sideleva, 2021). Given that what was considered to be Cottus nasalis inhabits the Syr Daria basin upstream of Tajikistan, and Cottus jaxartensis is recorded from the Syr Darya basin downstream of Tajikistan (Chirchik River), this species can be considered to inhabit Tajikistan, but for confirmation reliable occurrences are needed.
Diptychus maculatus Steindachner, 1866 (Cyprinidae)
Diptychus maculatus Steindachner, 1866: 788. Type locality: Lei, Tibet.
References for Tajikistan: Diptuchus maculatus — Rasulov (2011: 303, 535): upstream Syr Darya.
Comments: Nikolskiy (1938) mentions this species without concrete evidence for its occurrence in Tajikistan.
Glyptosternon oschanini (Herzenstein, 1889) (Sisoridae)
Exostoma oschanini Herzenstein, 1889: 70 Type locality: Upper Syr Darya, Ugam River.
References for Tajikistan: None.
Comments: This species inhabits the mountain tributaries of the upper reaches of the Syr Darya in Kyrgyzstan (Thoni et al., 2017), and thus likely inhabits mountain tributaries of the Syr Darya Basin in Tajikistan.
Gymnodiptychus dybowskii (Kessler, 1874) (Cyprinidae)
Diptychus dybowskii Kessler, 1874: 55. Type locality: Aksu River, Turkistan.
References for Tajikistan: Diptuchus dybowskii — Rasulov (2011: 302, 536): Upstream Syr Darya, Tarim drainage.
Comments: The known distribution of species is located east of Tajikistan's borders. Nikolskiy (1938) suggested that the species can be found in the Syr Darya basin in small rivers flowing from north of the Alai Range. However, there are no records in Tajikistan (Akhrorov, 2006).
Hedinichthys yarkandensis (Day, 1877) (Nemacheilidae)
Nemacheilus yarkandensis Day, 1877: 796. Type locality: Yarkand, Pas Robat, Yankihissar, and Kashgar, all from waters in connection with Yarkand and Yankihissar rivers.
References for Tajikistan: Nemachilus yarkandensis — Nikolskiy (1938: 159): possibly in Tarim basin within Tajikistan.
Comments: There is no reliable information about this species within Tajikistan.
Parabramis pekinensis (Basilewsky, 1855) (Xenocyprididae)
Abramis pekinensis Basilewsky, 1855: 239 Type locality: rivers leading to Tschili [Chihli] Bay, China.
References for Tajikistan: None.
Comments: Invasive species in the region. It can potentially inhabit the slow-flowing waters of the Amu Darya and its large tributaries. Its presence is indicated in the Amu Darya in Afghanistan (Çiçek et el., 2023: 32).
Introduced Species, Not Naturalized in Natural Water Bodies
Acipenser baerii Brandt, 1869 (Acipenseridae)
Acipenser baerii Brandt, 1869: 115. Type locality: Ob and Lena rivers systems.
References for Tajikistan: Acipenser baerii — Afanasyev et al. (2020: 369): Syr Darya including Kairakkum reservoir.
Comments: Single specimens have been caught in sporadic intervals in the middle reach of Syr Darya and in the Kairakkum reservoir (Afanasyev et al., 2020), however, evidence of natural reproduction is absent. It is like that individual escaped from aquaculture farms.
Coregonus nasus (Pallas, 1776) (Salmonidae)
Salmo (Coregonus) nasus Pallas, 1776: 79. Type locality: Gulf of Ob River, Russia.
References for Tajikistan: Coregonus nasus — Rasulov (2011: 500): Karakul Lake.
Comments: In 1986, 420,000 larvae were imported from the Tonsky fish factory on Lake Issyk-Kul to Lake Karakul (Rasulov, 2011). No reports of occurrence of the species have been made in the 21st century, and our field work at the lake yielded no specimens of this species. Further, there was no evidence in the local village of Karakul that this fish is harvested.
Coregonus peled (Gmelin, 1789) (Salmonidae)
Salmo peled Gmelin, 1789: 1379. Type locality: Pechora River, northern Russia.
References for Tajikistan: Coregonus peled — Rasulov (2011: 320): Yashilkul lake, Nurek reservoir.
Comments: In 1978–1980 about 5 million larvae were released into the Nurek reservoir; in 1979–1982 about 2.5 million larvae were released into the Yashilkul lake (Rasulov, 2011). The last record of Coregonus sp. was reported by Savvaitova et al. (1988).
Coregonus lavaretus (Linnaeus, 1758) (Salmonidae)
Salmo lavaretus Linnaeus, 1758: 310. Type locality: Lake Bourget, France.
References for Tajikistan: Coregonus lavaretus lavaretus — Rasulov (2011: 429, 533): Yashilkul.
Comments: Accidentally introduced in 1979 to Yashilkul lake from Novosibirskiy fish farm (Rasulov, 2011). After that, there are no reliable occurrences.
Hypophthalmichthys harmandi Sauvage, 1884 (Xenocyprididae)
Hypophthalmichthys harmandi Sauvage, 1884: 212. Type locality: Hanoi, Vietnam.
References for Tajikistan: Hypophthalmichthys molitrix harmandi — Rasulov (2011: 455): Khodzhamastonskoe fish farm (ex. Kuibyshevskoe, near Bokhtar).
Comments: There is no information on the presence of wild populations of this species in Tajikistan.
Leucaspius delineatus (Leuciscidae)
References for Tajikistan: Leucaspius sp. — Nikolskiy (1938: 131): lower reaches of Dushambinka R. (Varzob).
Comments: There is no more information on the record of this species or genus in Tajikistan. The native range of this genus is located in Central and Eastern Europe with a known invasive range in France (Freyhof and Kottelat, 2007) and Siberia (Interesova, 2012); this species may have accidentally come with other introduced species or the author mistakenly identified juveniles from a different genus (28.5 mm body length).
Ictalurus punctatus (Rafinesque, 1818) (Ictaluridae)
Silurus punctatus Rafinesque, 1818: 355. Type locality: Ohio River, United States.
References for Tajikistan: Ictalurus punctatus — Akhrorov (2006: 33): Tajikistan. Istalurus punctatus — Rasulov (2011: 436, 539): Tajikistan.
Comments: In the 1980s, I. punctatus was recorded in a fish farm in southwestern Tajikistan. Currently, it is not found in pond farms or in natural waterways and reservoirs of Tajikistan.
Ictiobus bubalus (Rafinesque, 1818) (Catostomidae)
Catostomus bubalus Rafinesque, 1818: 355. Type locality: Ohio River, United States.
References for Tajikistan: Ictiobus bufalus — Akhrorov (2006: 33): Tajikistan. Jctiobus bubalus — Rasulov (2011: 68, 533): Kuibyshev fish farm.
Comments: This species was imported to pond farms in Tajikistan in the 1980s (Rasulov, 2011). Currently they are not cultivated and are not found in natural bodies of water.
Ictiobus cyprinellus (Valenciennes, 1844) (Catostomidae)
Sclerognathus cyprinella Valenciennes in Cuvier and Valenciennes, 1844: 477. Type locality: near New Orleans, Lake Pontchartrain, Louisiana.
References for Tajikistan: Ictiobus cyprinellus — Akhrorov (2006: 33): Tajikistan. Jctiobus cyprinellus — Rasulov (2011: 67, 533): Kuibyshev fish farm.
Comments: This species was imported to pond farms in Tajikistan in the 1980s (Rasulov, 2011). Currently they are not cultivated and are not found in natural bodies of water.
Ictiobus niger (Rafinesque, 1819) (Catostomidae)
Amblodon niger Rafinesque, 1819: 421. Type locality: Mississippi, Ohio, and Missouri rivers, United States.
References for Tajikistan: Ictiobus niger — Akhrorov (2006: 33): Tajikistan. Jctiobus cyprinellus — Rasulov (2011: 67, 533): Kuibyshev fish farm.
Comments: This species was imported to pond farms in Tajikistan in the 1980s (Rasulov, 2011). Currently they are not cultivated and are not found in natural bodies of water.
Oncorhynchus mykiss (Walbaum, 1792) (Salmonidae)
Salmo mykiss Walbaum, 1792: 59. Type locality: Kamchatka, Russia.
References for Tajikistan: Salmo irrideus — Akhrorov (2006: 32): Tajikistan. Salmo gairdneri — Rasulov (2011: 479, 533): Nurek reservoir, fish farm ponds.
Comments: Cultivated as an aquaculture species. Naturalized populations are unknown. This species was not encountered in any of 52 sampling localities throughout the country, including through the use of angling equipment.
Mylopharyngodon piceus (Richardson, 1846) (Xenocyprididae)
Leuciscus piceus Richardson, 1846: 298. Type locality: Canton, China.
References for Tajikistan: Mulopharyngodon piceus — Rasulov (2011: 537, 22): fish farm ponds in Jami district.
Comments: This species was previously cultivated in the Kuibyshev fish farm (Halton district) and in other pond fish farms in neighboring Jami region (Rasulov, 2011). Not found in natural bodies of water in Tajikistan.
Misreported Species
Pseudohemiculter hainanensis (Boulenger, 1900) (Xenocyprididae)
Barilius hainanensis Boulenger, 1900: 961. Type locality: Five-fingers Mountains, Hainan Island, China.
References for Tajikistan: Hemiculter hainanensis — Zharov (1969): lower Vakhsh.
Comments: There are no reliable reports on occurrences of this species. Misidentification of similar species, Hemiculter leucisculus, is likely the case (Akhrorov, 2006).
Perccottus glenii Dybowski, 1877 (Odontobutidae)
Perccottus glenii Dybowski, 1877: 28. Type locality: Ussuri River area, Russia.
References for Tajikistan: Percottus glehnii — Rasulov (2011: 130, 539): Syr Daria, Vakhsh, Kafirnigan, Kairakkum reservoir, lowland lakes.
Comments: An invasive species in some places that became established as a result of the introduction of commercial fishes from the Far East. This species has been included in a species list (Rasulov, 2011) as dwelling in lowland waters, however, there are no reliable occurrences or vouchers either in the territory of Tajikistan or in neighboring territories (Sheraliev and Peng, 2021).
DISCUSSION
Species Diversity
The ichthyofauna of Central Asia, located at the junction of northern and southern Eurasia, on the one hand, combines species from northern and southern regions and, on the other hand, is characterized by increased endemism (Turdakov, 1963; Reshetnikov and Shakirova, 1993). The ichthyofauna of Tajikistan is represented by 60 confirmed species, which belong to 41 genera, 18 families, and 8 orders (fig. 6), and 23 additional species that fall into one of the following categories: extinct, never naturalized, unconfirmed, or otherwise dubious records. The most widely represented order (about 3/4 of species) is Cypriniformes (47 species), while Salmoniformes is represented by three species; Acipenseriformes, Gobiiformes, Perciformes, and Siluriformes are represented by two species each; and the remaining orders are represented by one species each (fig. 6). The most widely represented families are Leuciscidae (14 species), Nemacheilidae (13 species), and Cyprinidae (9 species), while the most diverse genera include: Triplophysa (8 species), Schizothorax (3 species; potentially more with revised taxonomies), and Gobio (3 species) (table 1).
Tajikistan is located in a region occurring at the junction of the endorheic basins of Central Asia with the Indian Ocean basin that, in turn, have influenced the local ichthyofaunal genesis. Endemic genera of the Amu Darya and Syr Darya riverine basins (with former tributaries, which currently are dead ends due to climatic aridization) are Aspiolucius, Capoetobrama, Dzihunia, Iskandaria, and Pseudoscaphirhynchus. Native species of the genera Abramis, Alburnoides, Alburnus, Ballerus, Capoeta, Luciobarbus, Pelecus, Petroleuciscus, Sabanejewia, and Scardinius inhabit the eastern or southeastern border of their ranges. The ranges of the genera Cottus and Esox are at their southern border in Tajikistan. The genera Glyptosternon and Schizothorax, which are greatly diversified in southern and southeastern Asia, are in the extremities of their range boundary in Tajikistan. Of the invasive genera, one is of American origin (Gambusia), one is of European origin (Sander), while the rest (Abbottina, Carassius, Channa, Ctenopharyngodon, Hemiculter, Hypophthalmichthys, Micropercops, Perccottus, Pseudorasbora, Rhinogobius, Rhodeus) are of Asian origin, mostly Chinese.
Currently two species can be considered endemic to Tajikistan (Triplophysa kafirnigani and Triplophysa lacusnigri), but further research is needed. The range of Triplophysa kafirnigani may be wider than known. We collected T. kafirnigani in the Karatog River, which connects via channels with the Kafirnigan River. This occurrence can be either within its natural range, which is insufficiently studied, or could be a result of dispersal via man-made channels. Based on this, it can be assumed that the species inhabits the Surkhandarya River basin, of which the Karatog River is a tributary, where it may be encountered in Uzbekistan. Triplophysa lacusnigri was previously considered to be endemic in Lake Karakul and its tributaries, but further research is needed, as there is a mention of the species in Lake Bulunkul (Vasil'eva and Nazarov, 2023). Once integrative taxonomic techniques resolve more of the problematic complexes in the region, more endemic taxa will likely be described.
FIGURE 6.
Taxonomic pie chart of the ichthyofauna of Tajikistan. The inner circle represents orders; middle circle, families; outer circle, genera with number of species.
Two species have very restricted ranges in Tajikistan: Petroleuciscus squaliusculus and Cottus spinulosus. Petroleuciscus squaliusculus was described by Kessler (1872) from springs near Khujand (Nau, Ak-Tyube) and Yany-Kurgan (along the Syr Darya). This is the only mention of this species' occurrences; all subsequent works were based on collection specimens (Nikolskiy, 1938; Berg, 1949; Bogutskaya, 2002). In 2017, we tried to collect this species around Khujand without success. Many springs marked on topographic maps have dried up. The flat areas along the upper and middle reaches of the Syr Darya are actively used for agriculture with irrigation, which could affect the change in hydrologic regime resulting in the disappearance of springs. Cottus spinulosus is currently known from two localities in Tajikistan around Khujand: springs in the area of Khujand (the type locality) and springs flowing into the Farkhad Reservoir near Khujand (Sideleva, 2021). The last occurrence was in 1954, and unfortunately the current status of the population is unknown.
The taxonomic status of species from five genera is not clear and need taxonomic revisions: Hemiculter (Xenocyprididae), Petroleuciscus (Leuciscidae), Rhinogobius (Gobiidae), Schizothorax (Cyprinidae) and Triplophysa (Nemacheilidae).
Hemiculter. Early sources (Vundtsettel, 1994) indicated that two species invaded the Syr Darya basin, but only H. leucisculus successfully naturalized in the basin. Afanasiev et al. (2020) reported on Hemiculter lucidus in Kairakkum Reservoir, probably citing an erroneous source. According to some distinctive morphology (Vasil'eva et al., 2022, 2022a) (the beginning of the dorsal fin is closer to the beginning of the caudal fin, a sharply curving lateral line at the pectoral fin, 11 unbranched rays in the anal fin, and 15–19 gill rakers on the first gill arch). Hemiculter in our catches from the Vakhsh, Kafirginan, and Kyzyl-Su rivers belong to the species Hemiculter leucisculus.
Schizothorax. Our mtDNA study shows that Schizothorax species from the Syr Darya, Amu Darya, and Zeravshan river basins belong to three geographically isolated clades. The same results were obtained for these basins in neighboring Uzbekistan (Sheraliev and Peng, 2021). Each clade exhibits three variations of the mouth apparatus, on the basis of which Berg (1949) identified morphs: typical; eurystomus (wide mouthed with a horny sheath); and fedtschenkoi (thick lipped). Morphs cooccur sympatrically and probably are not associated with habitat type as suggested by Turdakov (1963). However, one may suggest that Schizothorax can represent an example of adaptive radiation among polyploid fishes, similar to such in the genera Labeobarbus (Levin et al., 2019b, 2020).
Triplophysa. Most complex of these taxonomically troubled groups is the Triplophysa stolickai sensu lato, which is considered by some authors to be a group of species (Prokofiev, 2017), contrary to some other authors (Kottelat, 2012). A recently published study reported four different lineages of Triplophysa stolickai on the Qinghai-Tibetan Plateau with similar morphologies and suggested reclassifying them into four different species (Feng et al., 2019). Specimens from the upper reaches of the Zeravshan and Amu Darya, including Triplophysa lacusnigri from Lake Karakul, are closest to the lineage 4 (L4; Feng et al., 2019), which is spread in the east of the Qinghai-Tibetan Plateau.
Rhinogobius. Up to four species of Rhinogobius were reported for Tajikistan: Rhinogobius cheni, Rhinogobius cliffordpopei, Rhinogobius lindbergi, and Rhinogobius similis (Zharov, 1969; Akhrorov, 2006; Rasulov, 2011). Rhinogobius from Central Asia (Kazakhstan) was identified based on morphology as R. cheni (Vasil'yeva, 2007). Rhinogobius taxonomy is plagued with considerable confusion. Specimens from the Amu Darya, Syr Darya and Zeravshan basins from neighboring Uzbekistan have the same COI haplotype (Sheraliev and Peng, 2021) as the studied samples from Georgia, Azerbaijan (Japoshvili et al., 2020) and Iran (Zarei et al., 2021), and are a sister haplogroup to samples identified as R. nagoyae from Japan (Zarei et al., 2021). A hypothesis has been put forward that the species was introduced to the Gorgan Plain region in Iran as a by-product of the introduction of Asian carp (C. carpio), followed by dispersal to Central Asia, Iran, and Transcaucasia (Zarei et al., 2021), however, numerous cases of introduction might have also occured.
Petroleuciscus. According to morphological studies, Squalius squaliusculus, described by Kessler (1872), belongs to the genus Petroleuciscus (Bogutskaya, 2002). This species from the upper reaches of Syr Darya in Uzbekistan and Leuciscus lehmanni from the Zeravshan River are clustered together in phylogenetic trees based on the COI mtDNA marker (Sheraliev and Peng, 2021), all together very close to Leuciscus baicalensis. Nevertheless, authors concluded that Petroleuciscus squaliusculus and Leuciscus lehmanni are valid species, and that Petroleuciscus squaliusculus belongs to genus Leuciscus (Sheraliev and Peng, 2021).
Results presented above are for all river basins, with the exception of the Tarim Basin, an endorheic basin of the Tibetan plateau. The upper reaches of the Markansu River have a small catchment area within Tajikistan near the border with China. The environment in the headwaters of the Markansu River is unfavorable for fish survival: the water flowing from under the glacier has an extremely low temperature, and many streams are temporary. Studies of the ichthyofauna of this river in Tajikistan have not been carried out prior our work (Nikolskiy, 1938). We surveyed one site at high elevation and devoid of terrestrial plant life, yielding no fish. Representatives of the Tarim fauna of the genera Triplophysa, Hedinichthys, Schizothorax, and Schizopygopsis may inhabit the lower section of the Markansu River nearer the Tajik-Chinese border, however, due to the inaccessibility of the place for research and the lack of the proper occurrence data, we do not include these species in our list of fishes of Tajikistan.
Changes to the Ichthyofauna in the 20th and 21st Centuries
During the 20th century drastic changes occurred in the composition of the fish fauna of Central Asia, and Tajikistan, in particular. The largest of these changes was due to the intentional and unintentional introduction of fishes from the Far East and other regions, in order to increase the fish productivity of local water bodies. This resulted in a large increase of alien species; a number that elevated from zero at the beginning of the 20th century, to 16 species from 15 genera and 11 families. This process began in the 1930s and is still ongoing. The following commercially valuable species have been successfully naturalized in Tajikistan: Channa argus, Carassius cf. auratus, Sander lucioperca, Salmo ischchan, Ctenopharyngodon idella, Hypophthalmichthys nobilis, and Hypophthalmichthys molitrix, while some others were introduced but not naturalized: Coregonus nasus, Coregonus peled, Coregonus lavaretus, Hypophthalmichthys harmandi, Ictalurus punctatus, Ictiobus bubalus, Ictiobus cyprinellus, Ictiobus niger, Oncorhynchus mykiss, and Mylopharyngodon piceus. Unintentionally the following species were introduced and naturalized: Rhodeus ocellatus, Rhinogobius sp., Abbottina rivularis, Pseudorasbora parva, Micropercops swinhonis, Triplophysa strauchii and Hemiculter leucisculus. One species, Gambusia holbrookii, was successfully introduced in 1937 with the aim of reducing the spread of malaria (Maksunov, 1968, Vundtsettel, 1994, Rasulov, 2011).
Another massively consequential change was the collapse of the Aral Sea Basin ecosystem. This resulted in the extinction of some species (Salmo aralensis) or drastic decline of populations of other anadromous species that used the Aral Sea as feeding range and Syr Darya and Amu Darya riverine network as spawning and nursery ranges. Flow-regime alterations in the rivers feeding into the Aral Sea, via dam construction and large-scale water diversion for irrigation, combined with overfishing, and poaching, led disruptions in the community structure of fishes and ultimately to the disappearance of Acipenser nudiventris and Pseudoscaphirhynchus fedtschenkoi in the natural water bodies of Tajikistan (Mugue and Karimov, 2022c). Reservoir constructions also affected the ecology of species. Thus, L. brachycephalus formed resident populations in the Syr Darya and Amu Darya while Cyprinus carpio, Leuciscus aspius, Pelecus cultratus, Abramis brama, and Rutilus lacustris began to use reservoirs on the Syr Darya as feeding areas and exploit inflowing rivers for spawning (Salikhov and Kamilov, 1995). As a result of the construction of dams, flow rates decreased, seasonal fluctuations have dampened, and the settling of suspended solids in water led to an increase in its transparency (fig. 2A). The release of deep cold waters affected the temperature regime in the riverbed below the reservoirs. These changes might have led to a significant decline in the abundance of Capoetobrama kuschakewitschi and Aspiolucius esocinus in the Syr Darya (Salikhov and Kamilov, 1995). The intensive network of irrigation canals serves as corridors for range extension of fish species. For instance, the Alburnus chalcoides, which previously inhabited only the lower reaches of the Syr Darya, was found in 1993–1994 in the middle reach near the city of Bekabad on the borders of Uzbekistan and Tajikistan, where it could spread from the Zeravshan basin via canals (Salikhov and Kamilov, 1995). Our field survey of fish fauna of Tajikistan in 2017 confirmed further distribution of this species upstream on the Syr Darya. Triplophysa kafirnigani is not a native species in the Karatog River. Its colonization of the Karatog was likely facilitated by canals of irrigation systems joining this river with the Kafirnigan River basin. Triplophysa strauchii inhabits the basins of Balkhash, Sassyk-kul', Alakkul', and Issyk-Kul lakes. Recently it was found in the Syr Darya basin, where this species is considered an introduced one (Kayumova, 2020; Mamilov and Karimov, 2020e; Sheraliev and Kayumova, 2022; Sheraliev and Peng, 2021). Our discovery of Triplophysa strauchii in the Zeravshan basin expands its invasive range southward.
ACKNOWLEDGEMENT
Funding for this project was supported in part by the Field Museum of Natural History, Chicago.
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