Today, everybody agrees that freshwater biological diversity is threatened, so, we are particularly interested in the expanding knowledge of freshwater fishes, and of their taxonomic diversity as the very first step. The present revision is prepared within the project "Information Retrieval System (IRS) "Freshwater fishes of Russia" as a web-site. The main objective was to synthesize data on the diversity of agnathans and fishes living in continental lakes, rivers, streams and swamps of Russia. The object of the revision is a group of taxa representing originally freshwater forms, diadromous species and so-called "periferal" fishes that are marine groups that include persistent freshwater populations such as herrings, anchovies, needlefishes, gobioids, and soles. Data on introduced alien forms, both failed and established are also provided. Species with individuals that may move only sporadically into freshwater and Caspian Sea marine forms are excluded.

         The last edition of the classical Berg's monograph "Freshwater fishes of USSR and adjacent countries" (1948, 1949) is outdated and reflects the state of knowledge in taxonomy and nomenclature, and species concepts of 50-70 years ago. Quite recently, in 1998, "Annotated Check-List of Cyclostomata and Fishes of the continental Waters of Russia" and, in 2002, "Atlas of Russian Freshwater Fishes" in two volumes (Reshetnikov, Ed., 2002) were published though being a rather preliminary attempt to summarize updated faunistic data. Reviews on regional faunas (Bogutskaya & Naseka, 1997; Sheiko & Feodorov, 2000; Shed'ko, 2001; Chereshnev et al., 2001; Sideleva, 2001) have been also produced recently. Since 1949, numerous are taxomonic revisions giving new data to systematics of different groups. In general, changes in the formal content of the Russian freshwater fish fauna is very extensive. In the present revision, we use our own data on nomenclature of all forms in question, on taxonomy and distribution of Cyprinidae, Siluridae, and Bagridae, some Cobitidae, Percidae, Gobiidae, and data from literature critically analyzed on the other groups. It should be specifically emphasized that all publications containing original descriptions of all taxa under consideration were seen and their bibliographic data checked.

          The freshwater fish fauna of Russia mostly occupies the Palaearctic Realm, rivers and lakes currently or recently draining to the Arctic, western Pacific, Caspian, and eastern Atlantic. The numerically dominant families are: Cyprinidae (at least 92 species in 48 genera), Salmonidae (38-45 species in 8 genera), Gobiidae (30-32 species in 13 genera), Abyssocottidae (23-24 species in 7 genera), Cottidae (19-21 species in 7 genera), Coregonidae (at least 17-20 species in 3 genera), Acipenseridae (11 species in 2 genera), Cobitidae (at least 10 species in 4 genera), Petromyzontidae (9 species in 6 genera), and Clupeidae (at least 9 species in 2 genera). These ten families make up about 80% of the species in the fauna. Endemic to Russia are 33 species from 11 endemic genera and at least 37 species from non-endemic genera.

         Unrecognized and even formerly unseen species are found in the course of thorough taxonomic studies, especially in revisions of species-rich groups. Thus, there have been some relatively recent descriptions of Romanogobio pentatrichus, Rhodeus colchicus, Mesogobio tumenensis, Cobitis choii, C. tanaitica, Misgurnus nikolskyi, Mystus mica, Dallia admirabilis, Hypomesus chishimaensis, Salvelinus albus, S. elgyticus, S. kronocius, S. krogiusae, S. levanidovi, S. schmidti, S. gritzenkoi, Salvethymus svetovidovi, Batrachocottus talievi, Asprocottus korjakowi, A. minor, Neocottus thermalis, Procottus gotoi, Benthophilus mahmudbejovi, Gymnogobius taranetzi, Gymnogobius opperiens, Neogobius rhodioni, Tridentiger brevispinnis. At least 8-10 species are still unnamed. However, in general, the discovery of previously unknown species in Russian fresh waters is now uncommon.

         Several species, described by earlier authors and considered invalid by later ones, have been demonstrated to actually be distinct and valid: Alburnus hohenackeri, Phoxinus oxycephalus, Romanogobio tenuicorpus, some Salvelinus species, Thymallus brevirostris, and some others. Detailed taxonomic revisions showed that much could be gained from careful analysis of many morphological characters already at hand.

         The main source of recent species descriptions involves taxonomic concepts and practice. Application of species criteria that emphasize diagnosability or distinctness of populations (the Phylogenetic Species Concept or the Evolutionary Species Concept which for practical purposes are equivalent) over traditional geographically wide-spread, polytypic species results in an increase of recognized species. In fact, most earlier authors probably worked without paying much attention to concept formulations and their practical implications.

         For the first time in European ichthyology, Kottelat (1997) tried to explicitly define the species concept used and to use it consistently for all taxonomic groups. An example of a very fruitful discussion on the use of different species concepts in freshwater fish systematics can be found in his recent publications (Kottelat, 1997, 1998). However, nothing but agree with this author that a salient result of using the Phylogenetic Species Concept is that the subspecies category and the polytypic species simply disappear. So, many additions to the fauna of fresh waters of Russia are mostly subspecies (allopatric, divergent local populations) or sympatric but morphologically and ecologically different forms of different non-formal rank that are elevated to species status based on this new methodological approach (even in case it is not specifically formulated): Acipenser persicus, Alosa volgensis, A. tanaica, Barbus borysthenicus, B. escherichii, B. kubanicus, Chondrostoma kubanicum, Phoxinus czerskii, Rhodeus amurensis, Coregonus migratorius, Parasalmo penshinensis, Salmo ezenami, Brachymystax tumensis, some Salvelinus species, Thymallus grubii, and others. Salmonoids are notorious also for the existence in lakes and river-lake systems of several sympatric stocks that have been "classically" considered as different forms or races of a single species. In many cases, the "forms" are not only morphologically different, but have different habitats, prey on different organisms, and have different spawning seasons and spawning grounds. Those investigated are also genetically distinct (Pavlov et al., 1999; and others). Under any species concept, they are different species, and several of these "complex species" thus are groups of species or possibly species flocks (Lundberg et al., 2000).

         In taxonomy on the generic level, the most recent changes are synonymization of Alburnoides and Chalcalburnus with Alburnus (Bogutskaya, 1997), giving a rank of genus to former subgenera Romanogobio (Naseka, 1996) and Leocottus (Sideleva, 2001), description of new genera Cyphocottus (Sideleva, 2001) and Petroleuciscus (Bogutskaya, 2002). Completely new species composition is given to genera Chanodichthys (Bogutskaya & Naseka, 1997) and Gymnogobius (Stevenson, 2000; Shed'ko, 2001) based upon a special investigation of type-materials and nomenclature.

         Some species are endemic markers that delimit regional biotas. The most striking example is Lake Baikal. Here, Cottidae are represented by an endemic subfamily Cottocomephorinae with 3 genera and 8 species, and Cottinae with 1 endemic genera with 1 species; there are 2 endemic families as well, Comephoridae and Abyssocottidae, with, respectively, 1 genus and 2 species, and 7 genera and 23 (or 24) species. The Baikal fauna being a center of endemism, the Amur drainage is a nucleus of Russian freshwater diversity; its fauna is the largest with over 110 native species (18 endemic species among them and an endemic genus, Pseudaspius). Native faunas of river systems of the Caspian Sea in Russia possess a lower level of endemism with 6 endemic species only and one endemic genus, Caspiomyzon, but they are highly remarkable by their composition from ecological point of view: they include a very high number of semi-anadromous and anadromous species forming different stocks, ecomorphs and races.

          Fish faunas of different hydrographic regions differ greatly in their taxonomic composition and species richness. For example, in Lake Elgygytgyn (Chukotka Peninsula, the Anadyr' upper reaches), there are only three species permanently inhabiting the lake characterized by extremely severe conditions: Salvelinus boganidae, S. elgyticus и Salvethymus svetovidovi (two later taxa are endemic to the lake). In Khanka Lake, there are 74 native species from 55 genera; this number comprises about 72% of all the freshwater and anadromous species inhabiting the Amur basin and about 1/4 of all the freshwater fish species of Russia.

         The vast northern glaciated areas are depauperate because of cold climate and slow postglacial recolonization. At the same time, there are water bodies, mostly lakes, located at the upper reaches of Ob', Enisei and Lena (for example, Lake Teletskoje in the Ob' system) located much to the south but possessing, due to severe climate and specific hydrological characteristics, rather poor but unique fish faunas. The mentioned above Lake Teletzkoje is inhabited by only 13 species, but there occur two endemic forms of Coregonus (probably distinct species) and a morphologically peculiar form of Lota lota.

          The list of native freshwater species of agnathans and fishes (mainly exclusive of Caspian marine species and originally marine species incidentally found in brackish waters, estuaries and lower sections of rivers) reflects advances in recent freshwater fish taxonomy and new data on distribution and includes over 340 species in 132 genera and 29 families.

         Besides these, at least 26 alien species are introduced from out of the territory of Russia, but only some of them evidently known as established sustainable reproducing populations - Ictalurus punctatus, Salvelinus fontinalis, Oryzias sinensis, Gambusia holbrooki, Poecilia reticulata, Micropterus salmoides, Morone saxatilis.

         Over 115 species changes their native range during the last century. The most striking examples are natural invasions of Clupeonella cultriventris (formerly up to Volgograd; its invasion upstream: in 1964 recorded from Kuibyshev Reservoir, 1971 - Votkinsk Reservoir, 1975 - Kamskoje Reservoir, 1982 - Gor'kovskoje Reserver, 1990 and 1999 - Rybinskoje and Uglichskoje Reservoirs, respectively), and Osmerus eperlanus (native range in lakes of West Dvina to Pechora systems; its invasion downstream in the Volga system: from Lake Beloye to Ivan'kovskoje and Uglichskoje, then to Rybinskoje Reservoirs (1943), to Gor'kovskoje (1955), Kuibyshev (1959), and Saratovskoje Reservoirs where it is rather adundant now). Many species were intentionally introduces out of their ranges with fishery purposes (several Coregonus species and local forms, Oncorhynchus species, Sander lucioperca, Abramis brama - over 30 in total). A certain number of species were released from aquaculture sources (Hypophthalmichthys molitrix, Ctenopharyngodon idella, Salmo fontinalis, and other industrially stocked species), some were unintentionally introduced (for example, Perccottus glenii and Pseudorasbora parva with native ranges in the Amur drainage, now also widely distributed in Europe).

         Conservation efforts traditionally focused on maximization of commercial production; fish assemblages were considered to consist of valuable species and trash (coarse) species, only the former being worthy of protection. This situation gradually improved. The last edition of the Red Data Book of Russian Federation (Animals) (2001) includes 42 species (in total, 51 subspecies and local population). In taxonomic approach applied herein, the mentioned forms actually belong to 43 species: (category 0, probably extirpated or extinct) Acipenser sturio; (1, under threat of extirpation or extinction) Petromyzon marinus, Huso huso (Sea of Azov), H. dauricus (Zeya and Bureya Rivers), Acipenser mikadoi, A. schrenckii (Zeya and Bureya Rivers), A. ruthenus (Dnieper, Don, Kuban, Ural, Sura, Upper and Middle Kama), Salmo trutta (anadromous forms from Caspian and Black Sea), Hucho taimen (European part of Russia, Polar and Middle Ural), Brachymystax lenok (River Ob), Stenodus leucichthys (River Ural; European part of Russia), Barbus barbus, Elopichthys bambusa, Mylopharyngodon piceus (native population), Megalobrama skolkovii, Plagiognathops microlepis, Gadus morhua (Lake Mogil'noje, Kildin Isle); (2, reducing in number) Caspiomyzon wagneri, Eudontomyzon mariae, Acipenser baerii (Lake Baikal, River Ob'), Alosa volgensis, Salmo salar (lake form), S. trutta (anadromous form, lake form), S. ezenami, Salvelinus alpinus (Transbaikalian populations), Parahucho perryi (Sakhalin Island), Coregonus baerii (River Volkhov), C. albula (Lake Pereslavskoje), Thymallus thymallus (Upper Volga and Upper Ural), Rutilus frisii (Caspian Sea), Alburnus chalcoides (Sea of Azov), A. bipunctatus (European part of Russia), Silurus soldatovi, Siniperca chuatsi, Cottus gobio; (3, rare) Parasalmo mykiss, P. penshinensis, Salvelinus elgyticus, Salvethymus svetovidovi, Coregonus pidschian (Baunt Lakes), Prosopium coulterii, Sabanejewia caucasica, Sander volgensis; (4, undetermined status) Alosa fallax, Clupeonella abrau, Salmo trutta (river form Volga and Ural Rivers), Rutilus frisii (rivers of the Black Sea and the Sea of Azov). However, environmental laws and protection for endangered species is chaotic. Environmental conditions in Russia are widely regarded as deplorable, with aquatic ecosystems bearing much of the burden. There is hardly a big lake or river basin where the fish fauna has not become at least locally impoverished. Bearing these problems and uncertainties in mind, estimations of number of species at risk have to be viewed with scepticism. Given the oft-noted degradation of aquatic habitats from chemical and nutrient pollution, impoundment, introductions, salinization, dewatering, and overfishing and poaching, to name the most often cited agents, the conservative number would appear to underestimate true conditions.

© N.G.Bogutskaya, A.M.Naseka, 2000-2002
© Zoological Institute RAS, 2000-2002