Taxonomic status and origin of some ecological forms of whitefish <Emphasis Type="Italic">Coregonus lavaretus</Emphasis> (L.) from water bodies of Siberia

Molecular genetic analysis of some ecological forms of whitefish belonging to the Coregonus lavaretus (L.) complex from different water bodies of Siberia revealed a high degree of differentiation between them. On the basis of the analysis of the mitochondrial DNA protein-coding ND1 gene, it was demonstrated that the previously described ecological forms of C. anaulorum, Yenisei River whitefish, or Issatschenko’s whitefish (C. fluviatilis), and cisco-like whitefish from Lake Baunt were good biological species. Moreover, each ecological form was represented by a number of phylogenetic lineages, one of which was species-specific. The remaining lineages were characterized by the mitochondrial DNA of another whitefish species, usually, the most common in each geographic region. The results of genetic analysis demonstrated that the formation of modern ecological forms of Siberian pidschian-like whitefish was accompanied by natural introgressive hybridization. It is suggested that most of the modern pidschian-like whitefish species originated as a result of reticulate evolution.     

Natural genetic polymorphism and phylogeography of Siberian sturgeon <Emphasis Type="Italic">Acipenser baerii</Emphasis> Brandt, 1869

Five populations of Siberian sturgeon Acipenser baerii collected throughout the species distribution range (Lake Baikal, Lena, Yenisei, Kolyma, and Irtysh rivers) were examined for genetic polymorphism using five tetraploid microsatellite loci and the mitochondrial DNA control region. It was demonstrated that Siberian sturgeon was represented by genetically well-differentiated groups that corresponded to hydrographic basins, Ob–Irtysh, Baikal–Yenisei, Lena, and Kolyma. Population assignment of the Siberian sturgeon broodstock should be considered in the restocking programs.     

New data on the distribution of the Upper Lena form of grayling (Thymallidae) in the basin of Lake Baikal and its taxonomic status

The habitation of the Upper Lena form of grayling in the upper reaches of the Tiya (the northwestern tributary of Lake Baikal) and Barguzin rivers, where Baikal grayling Thymallus baicalensis Dyb. also occurs, was established. The listed forms can be diagnosed from the body coloration, dorsal fin pattern, combination of meristic characters, as well as by molecular-genetic methods. The sympatric habitation of the Upper Lena and Baikal graylings in the northern tributaries of Baikal, considerable phenotypic and genetic differences, as well as the absence of individuals with intermediate characters, make it possible to consider them as independent species. The results indicate the need to revise the intraspecies structure of the Arctic grayling T. arcticus (Pall.) and the entire genus Thymallus. The localization of populations of the Upper Lena grayling in the upper reaches of Baikal tributaries testifies to its possible penetration of the Baikal basin by means of temporary river catchments that formed in the past and which are probable at present at watersheds with the Lena River. A wider distribution of this form is apparently hindered by the pressure of aboriginal species.     

Phylogenetic relationships of sculpin <Emphasis Type="Italic">Cottus volki</Emphasis> Taranetz, 1933 (Scorpaeniformes,Cottidae) according to the results of analysis of control region in mitochondrial DNA

Sequencing of the fragment of control region in mitochondrial DNA in sculpin Cottus volki and the comparison of obtained data with homologous nucleotide sequences in the other species from genus Cottus demonstrated that C. volki occupies the basal position in the “poecilopus” group, which includes also typical sculpin C. poecilopus Heckel, 1837 from water bodies of Europe, sculpin C. szanaga Dybowski, 1869 from the Amur River basin, and sculpin Cottus cf. poecilopus from the Lena River basin. Early separation of C. volki line from common trunk of “poecilopus” group explains the presence in C. volki of several primitive (plesiomorphic for this group) morphological characters: long interior ray of ventral fin, practically complete lateral body line, and well-developed dentition of palatine bones.     

Colorless sulfur bacteria <Emphasis Type="Italic">Thioploca</Emphasis> from different sites in Lake Baikal

The colorless sulfur bacteria Thioploca spp. found in Lake Baikal are probably a marker for the influx of subterranean mineralized fluids. Bacteria act as a biological filter; by consuming sulfide in their metabolism, they detoxicate it and maintain the purity of Lake Baikal’s water. The bacteria were investigated by various techniques. According to analysis of the 16S rRNA gene fragment, Thioploca sp. from Frolikha Bay, Baikal belongs to the clade of freshwater species found in Lake Biwa and Lake Constance; it is most closely related to Thioploca ingrica.     

Decrease in young-of-the-year yellow perch growth rates following <Emphasis Type="Italic">Bythotrephes longimanus</Emphasis> invasion

Bythotrephes longimanus, an invasive zooplankter from Eurasia, has caused severe declines in native zooplankton communities in Rainy and Kabetogama lakes in northern Minnesota. Both lakes have experienced a 40–60% decrease in peak summer zooplankton biomass following B. longimanus establishment around 2006–2007. In these lakes, yellow perch (Perca flavescens) are a key fishery species, and young-of-the-year (YOY) yellow perch are mainly planktivorous during their first summer. This led to concern that their growth could be detrimentally affected by the depletion of zooplankton forage. We used seining data to compare growth rates of YOY yellow perch before (2001–2005) and after (2008–2012) B. longimanus establishment in Rainy and Kabetogama lakes. Nearby Lake Vermilion, assumed to have been unaffected by B. longimanus during this time period, was used as a reference for natural variation in YOY growth in the region. YOY yellow perch length was modeled as a linear function of cumulative growing degree days (GDD) throughout the summer, and the slope of the relationship was compared between pre- and post-B. longimanus time periods for the three study lakes. The two lakes with B. longimanus showed similar decreases in YOY yellow perch growth rate relative to GDD, whereas Lake Vermilion showed no evidence of a decline in growth rates during this period. The reduction in growth rates resulted in an approximate 10% decrease in mean length of YOY yellow perch at the end of the summer after B. longimanus establishment, which could lead to further effects of this invasive zooplankter at higher trophic levels.     

Heavy metal content and response of the blood system of Siberian dace <Emphasis Type="Italic">Leuciscus leuciscus baicalensis</Emphasis> (Cypriniformes,Cyprinidae) under anthropogenic impact

Chemical, hematological, and immunological characteristics of the Siberian dace Leuciscus baicalensis from different areas of Lake Baikal basin were first determined. It was established that the most considerable changes in hemopoesis, cellular, and humoral links of immunity were in individuals with a high content of heavy metals in the liver from populations inhabiting the Selenga River downstream the Ulan Ude Industrial Center and the Selenga Pulp-and-Cardboard Plant. Changes in immunohematological responses of L. leusiscus baicalensis from Cherkalov Bay of Lake Baikal proceeded within the adaptive possibilities of the species and indicated the development of compensatory reactions in response to the accumulation of heavy metals in the body. The results obtained make it possible to assert that Chivurkuiskii Bay of Baikal may serve as a control polygon during monitoring of immunobiological states of fish populations from Baikal basin.     

Lipid composition in muscle and liver of sympatric coregonid fishes from Lake Baikal (<Emphasis Type="Italic">Coregonus</Emphasis> spp.) under common garden experiment

The content of total lipids, total phospholipids, and fatty acids of total lipids in muscles and liver of juvenile Lake Baikal sympatric coregonid fishes have been analyzed for the first time under a common garden experiment. Baikal omul, Coregonus migratorius Georgi, is an active migrant of the pelagic zones of the lake. Baikal (lacustrine) whitefish, C. baicalensis Dybowski, is a colonizer of the bottom habitats, which are relevant to the pelagic zones of the littoral and underwater slope. Structural lipids (phospholipids and cholesterol) dominated in total lipids of the tissues of all fish under study. Spare lipids significantly prevailed in omul muscles when compared to whitefish. The highest variability of fatty acid composition was reported in muscles of coregonid fishes. Statistically significant differences were revealed in the content of the ω3 polyunsaturated fatty acids in muscles of lacustrine whitefish and omul. Associations of lipid compositions revealed in tissues of the whitefishes under the study with their respective ecotypes have been discussed.     

Genetic polymorphism,haplotype distribution,and phylogeny of <Emphasis Type="Italic">Daphnia</Emphasis> (Cladocera: Anomopoda) species from the water bodies of russia as inferred from the 16S mtDNA gene sequencing

The data on the genetic polymorphism of the most widespread Daphnia species occupying different water bodies of Russia are presented. The phylogenetic relationships between the examined species were established, and the haplotype networks were constructed. A fragment of the 16S mitochondrial DNA gene was used as a genetic marker. The results of molecular phylogenetic analysis generally coincided with modern concepts in the systematics of the genus Daphnia. The representatives of the divergent mitochondrial lineages within the D. longispina, D. pulex, and D. magna complex remain poorly investigated morphologically. For D. dentifera, a new habitat on the territory of Russia, namely, the water bodies of the Lake Baikal basin, was identified. A conclusion was made that the 16S mtDNA gene could be successfully used in phylogeographic analysis of the genus Daphnia.     

Linear growth of sparsely rakered whitefish <Emphasis Type="Italic">Coregonus lavaretus</Emphasis> (Coregonidae) of the Imandra Lake (Murmansk oblast)

This paper studies the properties of linear growth in sparsely rakered whitefish Coregonus lavaretus in the stretches of the large subarctic Imandra Lake, which are characterized by the diversity of habitat conditions and anthropogenic stress levels. The groups of sparsely rakered whitefish that are confined to different areas of the lake are marked out based on the properties of growth, trophic status, and anthropogenic stress intensity. A direct relationship of the linear growth in whitefish with the age of sexual development and trophic level of its habitats is found.     

Comparative Analysis of Content of Omega-3 Polyunsaturated Fatty Acids in Food and Muscle Tissue of Fish from Aquaculture and Natural Habitats

Two fish species reared in aquaculture (pink salmon Oncorhynchus gorbuscha and whitefish Coregonus lavaretus) and ten fish species from natural habitats (whitefish C. lavaretus, tugun Coregonus tugun, broad whitefish Coregonus nasus, least cisco Coregonus sardinella, vendace Coregonus albula, boganid charr Salvelinus boganidae, charr Salvelinus alpinus complex, northern pike Esox lucius, sharp-snouted lenok Brachymystax lenok, and taimen Hucho taimen) have been studied. The content of two long-chain polyunsaturated omega-3 fatty acids (PUFAs), eicosapentaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA), in the muscle tissue of the fish and in their food (intestine contents) are compared. In the aquacultures of whitefish and pink salmon, the total content of EPA and DHA is significantly higher in feed than in the muscle tissue of the fish, which indicates losses of PUFA in the two-link food chain of the aquaculture during their transfer to the upper trophic level. EPA and DHA losses in aquaculture, which are confirmed by numerous literature data, mean an inefficient usage of the available sources of PUFAs and the aggravation of the global deficit of these biochemicals in the human diet. A study of natural fish populations reveals the accumulation of EPA and DHA in their biomass compared to food in many cases, although opposite phenomena are also observed. An assumption on the presence of an optimal, physiologically adequate species-specific level of PUFA in the fish muscle tissue has been made based on our data and literature data. If the level of PUFAs in the muscles is lower than optimal, their accumulation (bioaccumulation) from food and/or de novo synthesis are observed. When the optimal level is exceeded, the content of EPA and DHA in biomass approaches maximum species-specific values; however, part of these PUFAs entering from food is not digested or is catabolized. According to the obtained data, the species of the order Salmoniformes have an optimal level of 2 to 6 mg/g of wet weight. It has been found that in aquaculture approaching to maximum values of EPA + DHA content was accompanied by their losses (scattering) in the food chains, while in natural ecosystems the maximum values of PUFA content in the fish biomass are achieved by their accumulation from the lower trophic level. Boganid charr S. boganidae had the highest content of EPA + DHA in the muscle tissue among all known fish species (32.78 mg/g of wet weight).     

Redescription and systematic position of nominal loach species <Emphasis Type="Italic">Nemacheilus compressirostris</Emphasis> and <Emphasis Type="Italic">N. sibiricus</Emphasis> (Nemacheilidae)

Type specimens of nominal species Nemacheilus compressirostris Warpachowsky, 1897, and N. sibiricus Gratzianov, 1907, from the upper Ob River basin were redescribed, and lectotypes for both species were selected. Although some traits were not preserved well enough, it was established that both names should be classified with Barbatula cf. toni, corresponding to the “snub-nosed” morphotype fide Prokofiev (2007). None of the names are suitable for designation of the morph “tigris” fide Gundrizer (1975) and Prokofiev (2007). A comparison table of diagnostic traits of the genus Barbatula from the Asian part of the range was compiled.     

Specific features of structure and functioning of gill-jaw apparatus of whitefish <Emphasis Type="Italic">Coregonus lavaretus pravdinellus</Emphasis>

The food spectrum of multirakered whitefish Coregonus lavaretus pravdinellus was studied. It was shown that C. lavaretus pravdinellus feeds mainly on large zooplankton; however, it also consumes nauplii whose average sizes are considerably smaller than the intergill distance. This fact counts in favor of the view of the active functioning of gill rakers. The type of feeding of C. lavaretus is related to a set of morphological characters of the gill-jaw apparatus and the head, such as the number of gill rakers, the length of the upper and lower jaws, mouth position, and the shape and slope of the snout tip area. A great number of gill rakers allows coregonids to use as food a wider size range of prey.     

New species of <Emphasis Type="Italic">Jakutoproductus</Emphasis> from the Lower Permian of Verkhoyansk Region

Two new brachiopod species of Jakutoproductus, J. lenensis sp. nov. and J. talchanensis sp. nov., are described. J. lenensis occurs in the upper part of the J. verkhoyanicus Zone of the Khorokytian Horizon (Asselian–Sakmarian deposits) of the lower reaches of the Lena River and in the Sobolokh-Mayan and Allara-Khadaryn’ya river basins. J. talchanensis is identified from the Khorokytian Horizon of the Talchan River (Baraiy River basin). A new subzone, the J. lenensis Subzone, is proposed for the upper part of the J. verkhoyanicus Zone of the Khorokytian Horizon of the Verkhoyansk Region.     

Genetic divergence of sympatric charrs of the genus <Emphasis Type="Italic">Salvelinus</Emphasis> from Nachikinskoe Lake (Kamchatka)

We studied genetic differentiation of two charr species, Dolly Varden Salvelinus malma malma Walbaum and resident lacustrine charr Salvelinus sp., which sympatrically inhabit Nachikinskoe Lake (the Bol’shaya River basin) in southwestern Kamchatka Peninsula. Using restriction analysis (RFLP), three mitochondrial DNA fragments (ND1/ND2, ND5/ND6, and Cyt b/D-loop) amplified in polymerase chain reaction (PCR) were compared. The divergence of the mtDNA sequences between Salvelinus sp. and S. malma malma was 2.8%; Salvelinus sp. and S. taranetzi, 0.36%; Salvelinus sp. and S. krogiusae, 0.21%; Salvelinus sp. and S. alpinus, 3.0%. These results point to reproductive isolation of charrs in Nachikinskoe Lake and support the earlier suggestion on a close relationship between Salvelinus sp., S. taranetzi, and S. krogiusae.     

Characterization of invasive fish species in a river transposition region: evolutionary chromosome studies in the genus <Emphasis Type="Italic">Hoplias</Emphasis> (Characiformes,Erythrinidae)

Karyotypic analyses were performed in fishes from the genus Hoplias (H. malabaricus and H. lacerdae groups) from the São Francisco River basin (Brazil), in an impacted region by a river transposition which altered the local ecology and fish fauna. The karyotypes were investigated using chromosomal markers obtained from classic and molecular cytogenetics (Giemsa, CMA₃ and DAPI staining, C-banding, Ag-NORs, and FISH with 18S rDNA, 5S rDNA and 5SHindIII satellite DNA probes). Two karyotypic forms were found for the H. malabaricus group—karyomorph F, corresponding to the native form from the São Francisco River basin, and karyomorph A, corresponding to the invading form from the Upper Paraná River basin. Specimens from the H. lacerdae group exhibited striking chromosome differences in relation to the H. malabaricus group, thereby enabling good cytotaxonomic characterization and inferences regarding the karyotype evolution of these groups.     

Detection and Genetic Characterization of Bacteria of the Genus <Emphasis Type="Italic">Pseudomonas</Emphasis> from Microbial Communities of Lake Baikal

The genus Pseudomonas is one of the most diverse and ecologically important groups of bacteria. Numerous representatives of the genus are found in microbial communities of all natural environments, including those closely associated with plants and animals. This ubiquitous distribution determines a necessity of their physiological and genetic adaptations. Molecular methods revealed that bacteria of the genus Pseudomonas were predominant in ulcerative lesions on the skin of Baikal yellowfin Cottocomephorus grewingkii (Dybowski, 1874). According to ribosomal phylogeny, cultivated Pseudomonas spp. isolated from both ulcerative lesions and the water column of Lake Baikal were grouped into the intrageneric cluster IG P. fluorescens. The topology of the phylogenetic tree based on the gene for outer membrane porin OprF generally coincided with that based on the 16S rRNA genes at the intrageneric level; however, it reflected ecological features of the strains of the genus Pseudomonas at the subgroup level. Screening of pathogenicity determinants detected the oprL, ecfX, fliC, and algD genes in the genomes of Pseudomonas spp. isolated from the ulcerative lesions of fish, whereas oprL and gyrB genes were determined in the strains isolated from the water column.