Lavaretus Pidschian Research Articles

Causes of Morphological and Genetic Heterogeneity of White Fish <i>Coregonus lavaretus</i> sensu lato in the Arctic Part of the Lena River Basin

The results of the morphological and genetic analysis of populations/forms/species of tanned whitefish from the middle and lower reaches of the river are presented. Lena, and adjacent rivers. There are reasons to believe that, despite the significant heterogeneity of whitefish in Siberia, a small number of stable forms/species inhabit the water bodies of the Siberian Arctic. These are East Siberian (C. lavaretus pidschian n. brachymystax), glacial plain (C. lavaretus pidschian n. glacialis), and Yukagir whitefish (C. lavaretus pidschian n. jucagiricus), as well as their hybrid populations. The glacier-plain whitefish and its derivatives differ from the East Siberian whitefish in plastic features, but they are identical in meristic ones. Molecular genetic studies have shown that in most glacier-plain whitefish form extensive loosely connected networks of haplotypes, which corresponds to the long-term existence of populations in favorable conditions. The East Siberian whitefish haplotypes are closely related to the whitefish haplotypes from the water bodies of Southern Siberia and have a radial structure. Such a structure of median networks indicates a recent decline in the number of East Siberian whitefish followed by expansion, which is directly related to the events of the Quaternary glaciations.

Metapopulation Structure of Two Species of Pikeworm (Triaenophorus, Cestoda) Parasitizing the Postglacial Fish Community in an Oligotrophic Lake.

In the present study, we estimated the levels of infestation of the main fish species that are hosts for two Triaenophorus species: T. crassus and T. nodulosus. The prevalence of T. crassus and T. nodulosus infestations in the intestine of their definitive host-pike Esox lucius was similar (71.0% and 77.4%, respectively). At the same time, the prevalence of T. crassus infestation in muscle tissue was significantly different between the second intermediate hosts, Coregonus lavaretus pidschian (31.4%) and Cor. l. pravdinellus (91.2%), due to considerable differences in their diets. For T. nodulosus, we found significant variations in the levels of prevalence among the second intermediate hosts-100% for Lota lota, 81.8% for Cottus sibiricus 31.9% for Thymallus arcticus, and 24.5% for Perca fluviatilis-that we also explained using different diets. Moreover, analysis of the symmetry of parasite infestations did not reveal any asymmetry between the number of cysts in the left and right body surfaces of the "planktivorous" form/species of whitefish, whereas in the ''benthivorous", an asymmetry of parasite infestations was found.

Intraspecific structure of the Coregonus lavaretus complex in water bodies of Siberia: a case of postglacial allopatric origin of Yukagirian whitefish

The results of morphological and genetic analyses of forms/species of the Coregonus lavaretus pidschian (Gmelin, 1789) complex from the Indigirka and Kolyma river basins are presented in the context of there being recent postglacial speciation events. It has been found that the studied whitefishes belong to the sparsely rakered and low lateral-line forms and have previously been described as Coregonus lavaretus pidschian n. jucagiricus Drjagin (Berg), 1932. Based on these characters, this whitefish does not differ from most Arctic whitefish populations (in particular from Coregonus lavaretus glacialis Kirillov, 1972). Analysis of variability of the ND1 gene (mtDNA) showed that whitefishes from the Indigirka and Kolyma basins belong to a distant phylogenetic lineage, which is significantly different from all previously studied whitefish lineages from the Ob, Yenisei, Lena, Anadyr, and Amur river basins. Analysis of variability of the ITS1 fragment (nDNA) showed that all studied forms/species (from Ob River to Amur River basins), including C. l. pidschian n. jucagiricus, have a tandem arrangement of two identical nucleotide fragments and very similar nucleotide composition of the ITS1 region. Based on contemporary data, this phylogenetic lineage of the C. pidschian complex could be considered a young postglacial allopatric species.

Evidence of dispersal between the Yenisei and the Lena river basins during the late Pleistocene within the whitefish (Coregonus lavaretus pidschian) complex

The Coregonus lavaretus (Linnaeus, 1758) complex is a morphologically and genetically diverse group of whitefish. Its taxonomic structure has been controversial for almost a century. At least 25 forms of C. lavaretus have been described in Siberia, but there is still no consensus on their intraspecific structure and taxonomy. Coregonus lavaretus pidschian (Gmelin, 1789) was described as a subspecies of C. lavaretus. Recently, it was assumed that this subspecies is also a complex. The purpose of this study was to compare the distributions of pidschian-like whitefish haplotypes in two basins of large Siberian rivers, Yenisei and Lena, and to assess the gene flow between basins of these rivers, which were connected after the last glaciation. The sequence of the following mitochondrial DNA genes, 16S rRNA (partial), tRNA-Leu (full), NADH dehydrogenase subunit 1 (full), tRNA-Ile (full), and tRNA-Gln (partial), were used for the inference of intraspecific genetic structure of C. l. pidschian. Whitefish haplotypes were clustered into two groups according to their distribution between two large Siberian river basins; however, there were shared haplotypes indicating events of migration and hybridization, which could occur when Bolshoi Yenisei and Lena river systems were connected after the last glaciation (the Late Pleistocene).

Feeding habits shape infection levels by plerocercoids of the tapeworm Triaenophorus crassus in muscle of a sympatric pair of whitefish in an oligotrophic lake.

Lake Teletskoye (West Siberia, Russia) is inhabited by a sympatric pair of whitefish, with each member of the pair being characterized by different feeding habits. Coregonus lavaretus pidschian (Gmelin, 1789) is a large 'benthivorous' form, while C. l. pravdinellus (Dulkeit, 1949) is a small 'planktivorous' form. Fish were collected from the end of August to the middle of September in 2017 and 2019-2020 in the north part of Lake Teletskoye. For the 'benthivorous' form the prevalence, intensity and abundance of T. crassus ranged from 22.4% to 51.9%, 1.9-2.8 and 0.4-1.3, respectively, whereas the same indices for the 'planktivorous' form ranged from 94.7% to 97.5%, 4.2-4.8 and 4.0-4.7, respectively. The level of prevalence of infection and abundance of T. crassus in muscle was relatively stable among studied years for both forms. The level of prevalence was higher in the years 2019 and 2020 than in 2017 for the 'benthivorous' form, whereas for the 'planktivorous' form this index did not change during the studied years. For the first time, a partial sequencing of the cox1 gene (593 bp) for T. crassus was sequenced. All 15 plerocercoids of T. crassus were represented by four haplotypes.

The effect of diet on the structure of gut bacterial community of sympatric pair of whitefishes (Coregonus lavaretus): one story more.

In the Coregonus lavaretus complex may be found lacustrine sympatric pairs, which serves as an intriguing model for studying different aspects of fish evolutionary biology. One such sympatric whitefish pair inhabits Teletskoye Lake (West Siberia, Russia) and includes a “large” form (Coregonus lavaretus pidschian (Gmelin, 1789)) and a “small” form (C. l. pravdinellus (Dulkeit, 1949)). C. l. pravdinellus has a narrow trophic specialization and feeds on zooplankton, whereas the diet of C. l. pidschian is based on benthic prey. In the present study we aimed to address the question of how the gut microbial community reflects the divergence in diet of a sympatric pair of whitefish. Studied samples included the mucosa and content were collected for cardiac and pyloric stomach, anterior, middle, and posterior intestine, but only mucosa was collected for the pyloric caeca. In addition, water, sediment, macrophyte (environmental microbiota) and invertebrate (microbiota of prey) samples were collected in the same location. The V3–V4 region of the 16S rRNA genes was chosen for microbiome analysis and the software PICRUSt used to estimate the difference functional roles of the microbiota. The number of OTUs and Chao1 index in mucosa and content of cardiac and pyloric stomach were significantly different between whitefish. Significant differences were observed between whitefish for content from different parts of the intestine in terms of OTU number and Chao1 indices, whereas for mucosa from the same parts of intestine these differences were absent. No significant differences were found for diversity estimates of mucosa and content of different parts of the gut (there were a few exceptions) between whitefish. The form of whitefish and the segment of the digestive system were factors with a significant determinative effect on the structure of the microbiota from gut mucosa and content. The most dominant phyla in mucosa and content of cardiac and pyloric stomach was Proteobacteria (57.0–84.0%) for both whitefish. Throughout the intestine of C. l. pidschian the dominant phyla in mucosa were Proteobacteria (38.8%) and Firmicutes (15.6%), whereas for C. l. pravdinellus–Tenericutes (49.6%) and Proteobacteria (28.1%). For both forms, the phylum Spirochaetes was found in a significant amount (20.0–25.0%) in the mucosa of the posterior intestine. While for the content obtained from anterior, middle and posterior intestines, the dominant bacterial phyla were the same as those described for mucosa from the same parts of the intestine for both whitefish. The bacterial community of the prey and environment was significantly different from bacterial communities found for all parts of the gut mucosa for both whitefish, with the exception of the mucosa of the cardiac stomach. According to PICRUSt the highest level of differences between whitefish at the L3 level were found for the intestinal mucosa (75.3%), whereas the lowest one was registered for stomach content (38.8%).

The Long-Term Dynamics of Parasite Infection in Coregonids with Different Food Specializations

The long-term dynamics of the parasitic infection of two coregonid species with different food specializations, peled Coregonus peled (Gmelin, 1789) and Siberian whitefish Coregonus lavaretus pidschian (Gmelin, 1788), during spawning migration in the Synya River (a Polar Urals tributary of the Lower Ob) has been studied. The differences in the parasite species composition and infection of the two fish species are determined their food spectra features, as well as by their use of different biotopes in feeding water bodies and the interannual dynamics of the fish age composition. A trend towards a decrease in the rate of peled infection by myxosporidium and cestode with a simultaneous decrease in its abundance due to intensive catches has been revealed. The stability of the composition of the coregonid parasite fauna in the Ob lower reaches indicates stable relationships between parasites and hosts and a relatively stable state of the ecosystem of the Lower Ob.

The reasons of genetic heterogeneity of Siberian whitefish Coregonus lavaretus pidschian in the Anabar river

Background. A population genetic study of Siberian whitefish or pidschian Coregonus lavaretus pidschian Gmelin of the Anabar River (North-West Yakutia) has been done to study genetic structure of the species within a river system and for revealing its phylogeographic relations.
 Materials and Methods. Five samples of pidschian from different parts of the river were analyzed for 30 isozyme loci.
 Results and Discussion. The results has demonstrated a significant genetic heterogeneity of the species sampled from lower and middle reaches of the river (0.001 DN 0.056). The most likely reason for genetic differentiation of the species within the river system is a colonization of the watershed by independent phylogenetic lineages of whitefish. At present the phylogenetic lineages in Anabar River are presented by sympatric ecological forms of the species eastern-siberian whitefish and glacial-plains whitefish which maintain their reproductive isolation. The relationships of ecological forms of whitefish dwelling the Anabar River with other populations of the species in Siberia, and possible ways of penetration of discrete phylogenetic lineages of pidschian in the basin of studied river are discussed.
 Conclusions. A genetic heterogeneity of whitefish from Anabar River should be taken into account while creating adequate intraspecific taxonomy and considered in conducting fisheries and environmental measures.

Hybridization between different lineages of pidschian-like whitefishes (Coregonus lavaretus pidschian, coregonidae) in water bodies of Southern Siberia

Summary: Background. The purpose of this work was studying of interaction between morphologically similar forms of the pidcshian-like whitefishes inhabiting restricted territory of riverine-lacustrine system situated in the Bolshoi Abakan Rriver basin.
 Material and methods. In the morphological analysis were used 141 whitefish individuals from Lake Karakul and 26 from the Bolshoi Abakan River. In the genetic analysis 11 and 26 whitefish individuals were used respectively. For them the sequences of a gene 16S-ND1 of mitochondrial DNA (mtDNA) and ITS1 of nuclear DNA (nDNA) were defined.
 Results. The whitefish populations clear differ on the gill raker numbers on the first branchial arch, growth. The analysis of the 16S-ND1 mtDNA genes variability revealed among them several divergent lineages and two lineages were revealed on the structure of ITS1 fragment of the nDNA.
 Conclusions. Based on the obtained data it is proved that two genetically divergent populations of the morphologically same forms of pidcshian-like whitefishes inhabiting the riverine-lacustrine system (the Bolshoi Abakan River Lake Karakul). Our results are supported a hypothesis of multiple hybridization between week differentiated populations/form of pidcshian-like whitefishes in habiting region during the postglacial period.

The dependence of the duration of sperm motility in Ob–Irtysh basin coregonidae on temperature

The duration of sperm motility in four whitefish species in the Ob–Irtysh basin, namely, Coregonus tugun, the river and lake forms of C. peled, C. lavaretus pidschian, and C. nasus, has been studied. It is shown that the duration of sperm motility in these species has a statistically significant inversely proportional dependence on the temperature of the water that is used for activation. The total duration of sperm motility at the spawning temperature in the range from 0.1 to 5.0°C amounts to 331 ± 107 s, on average, while the duration of forward movement amounts to 149 ± 44 s, on average. At temperatures that exceed the spawning values (above 7.1°C), these parameters constitute 190 ± 47 and 86 ± 15 s, respectively. The highest interspecific variability in the duration of sperm motility was observed within the temperature range from 0.1 to 2.5 and above 7.1°C. C. tugun shows less dependence of the duration of sperm motility on temperature than the other species under study. At a temperature of 0.7°C, the total duration and duration of the forward movement of C. tugun sperm are 201 and 108 s, respectively. When the temperature was increased to 13.4°C, these parameters decreased by 1.2 and 1.1 times only, i.e., to 172 and 100 s, respectively.

Genetic diversity of Diplomonadida in fish of the genus Coregonus from Southeastern Siberia.

Diplomonadida are primitive flagellate protozoa, among which both commensals and pathogens have been recorded. To date, members of the genera Hexamita and Spironucleus have been reported in the digestive system of fish in the Baikal region. We determined the genetic diversity of Diplomonadida in fish of the genus Coregonus from south-eastern Siberia using molecular-genetic methods. Fish for analysis were caught in Lake Baikal and in the Barguzin, Nepa, Chechuy, and Kirenga rivers from 2010 to 2013. Gall bladders, hindguts and foreguts of 120 specimens of Coregonus migratorius representing three morpho-ecological groups, 25 specimens of Coregonus lavaretus baicalensis, 25 specimens of Coregonus tugun and 30 specimens of Coregonus lavaretus pidschian were analysed via amplification with primers specifically designed for eukaryotes. Amplicons positive for Diplomonadida were sequenced. A phylogenetic analysis revealed that diplomonad flagellates of whitefish from Southeastern Siberia belong to Spironucleus barkhanus. Positive Diplomonadida DNA samples were analysed with primers designed in the present study for the amplification of small subunits of ribosomal DNA fragments of S. barkhanus (about 1,430 bp) and sequenced. Phylogenetic analysis revealed inside the clade of S. barkhanus besides the cosmopolitan genotype from European salmon that was detected earlier in Baikalian grayling, a new genotype unique to the fish of the genus Coregonus from Lake Baikal.

Feeding of whitefish Coregonus lavaretus pidschian (Coregonidae) in the lower reaches of the Northern Dvina River

Analysis was performed of the feeding of whitefish in the basin of the Northern Dvina River, including the tributary of the first order—Emtsa River and the middle course of the river, its delta part, and sites of the near-mouth offshore. It was established that, according to the pattern of feeding, whitefish is a euryphage with sufficiently wide food spectrum, including over 40 groups of food organisms at the level of classes, orders, families, and genera. The bulk of its feeding is formed by aquatic larvae of insects (mainly chironomid larvae), secondary food consists of mollusks, crustaceans, worms, and sponges. Changes in the feeding of whitefish depending on habitats, food biotopes, and difference with respect to years and seasons of the year, as well as on the age of fish, were revealed. Sufficiently high feeding intensity, as well as small changes in the feeding of whitefish in different years and at different sections of the channel indicate stable feeding conditions in the middle part of the Dvina basin. Food possibilities of the delta and the near-mouth offshore also satisfy trophic demands of the feeding school of whitefish.

Relief structure of scales in Coregonid fishes from Lake Baikal: differences between morpho-ecological groups of omul (Coregonus migratorius Georgy) and Siberian whitefish (Coregonus lavaretus pidschian Gmelin)

Relief structure of scales in Coregonid fishes from Lake Baikal: differences between morpho-ecological groups of omul (Coregonus migratorius Georgy) and Siberian whitefish (Coregonus lavaretus pidschian Gmelin)

Karyotype of the anadromous whitefish Coregonus lavaretus pidschian (Gmelin, 1788) from the Northern Dvina River (White Sea Basin)

The karyotype of anadromous whitefish from the Northern Dvina River was examined. The chromosomal complement consists of 9 pairs of biarmed chromosomes (8 pairs of meta- and 1 pair of submetacentrics) and 31 pairs of uniarmed (subtelo- and acrocentric) chromosomes, 2n=80, NF=98. The variability in the length of metacentrics of the first pair and the number of B-chromosomes was found.

Morphology and mitochondrial DNA variation of the Siberian whitefish Coregonus lavaretus pidschian (Gmelin) in the upstream water bodies of the Ob and Yenisei Rivers

Combining morphological, ecological and genetic analyses, we compared patterns of diversification within and among populations of the southern Siberian whitefish species Coregonus lavaretus pidschian (Gmelin) to illuminate their evolutionary history. Using sequencing data from 1,930 bp of NADH dehydrogenase subunit 1 (ND1) mitochondrial DNA regions, we documented phylogeographic relationships among populations and developed a phylogeny of mtDNA haplotypes. We found significant differences in the perforated lateral-line scale numbers within and between some populations. Clear differences in the number of gill rakers on the first branchial arch were only exhibited between populations of C. l. pidschian and Coregonus lavaretus pravdinellus Dulkeit. Concordance between different morphological groups based on two meristic traits and mtDNA patterns was also tested.

Population structure and hypothetic pathways of differentiation of whitefishes (Coregonus lavaretus pidschian, Coregonidae) in the Dodot lakes (the Khamsara River upstream)

We have studied morphology and ecology of whitefish Coregonus lavaretus pidschian (Gmelin) inhabits the Dodot lakes (Aldy-Deerlig-Khol and Ustyu-Deerlig-Khol) situated in the upstream of the Khamsara River (the Bolshoi Yenisei River basin, Tyva Region). The whitefishes were represented by lacustrine and river populations occupying similar ecological niches. We found significant differences in the perforated lateral-line scale numbers between populations. In conclusion, we suggest that this region is the secondary contact zone.

Genetic-biochemical analysis of hybrids between Arctic cisco Coregonus autumnalis migratorius and lake-river whitefish C. lavaretus pidschian from Lake Baikal

Among the natural hybrids of coregonid fishes in Lake Baikal, the hybrids of the first generation from crossing Arctic cisco Coregonus autumnalis migratorius and lake-river whitefish (pidschian) C. lavaretus pidschian are the most abundant. They are well-identified morphologically. The data of the analysis of allozyme variations confirm the validity of the morphological determination of different Baikal coregonid forms and their hybrids, but do not allow a strict evaluation of its accuracy.

Identification of palearctic coregonid fish species using mtDNA and allozyme genetic markers

Two types of molecular genetic markers were used for genetic identification of species and local stocks of palearctic coregonids (Coregonidae, Salmoniformes, Teleostei). Seven nominate species of whitefishes and ciscoes Coregonus, spp. of Eurasia Arctic Sea basin and inconnu Stenodus leucichthys nelma, represented by specimens from North America were studied. Using restriction analysis of PCR‐amplified products of the ND‐1 gene of mitochondrial DNA (mtDNA) and allelic composition at several allozyme loci discrimination was successful between C. lavaretus pidschian, Siberian whitefish, C. nasus, broad whitefish, C. autumnalis, Arctic cisco, C. migratorius, Baikal omul, C. peled, peled, and C. sardinella, least cisco. Muksun C. muksun, was indistinguishable from Siberian whitefish. Creatine kinase (CK) isozyme patterns and Rsa, I restriction patterns of ND‐1 were the most effective markers allowing discrimination among species. Intra‐specific differentiation in mtDNA was found in all species but was much less pronounced than inter‐species variation. In several specimens composite haplotypes typical of another species were found that reflect probable gene introgression by hybridization. A combination of mtDNA and nuclear genetic markers is suggested for reliable identification of both typical species representatives and hybrids.

The Effects of Low Temperatures on Larval Cestodes and Other Helminths in Fish

Our knowledge of the resistance of larval cestodes and other helminths to low temperatures has been derived mainly from the efforts of European investigators. In Russia, Titova (1955) employed two temperatures, -6? and -18?C, to determine the freezing time required to kill plerocercoid larvae of Diphyllobothrium latum L. in pike (Esox lucius). Her findings suggest that the time of freezing required to kill the larvae is roughly proportional to the weight of the fish. For example, at -6?C, 7 days of freezing were required to kill larvae in a 9 kg fish, whereas only 2 days were needed to accomplish similar results in a 700 gm fish. The Italian workers Scolari and Monzini (1954), using yellow perch (Perca fluviatilis) of comparatively uniform weight (70 gm), were able to kill encysted plerocercoid larvae of Diphyllobothrium latum by exposing the hosts to the following temperatures: 0?C for 20 days, -5?C for 72 hours, -15?C for 8 hours, -40?C for 2 hours. These findings led the writer to attempt to determine the survival capabilities during subjection to various low temperatures of some of the larval helminths occurring in fresh-water fishes of Alaska. Such determinations would le of interest for two reasons. (1) Knowledge of the comparative effect of temperature, limited to 1 species at present, would be extended to include several species of Diphyllobothrium, 1 of Triaenophorus, and ascarids (Porrocaecum sp.). (2) The information might prove useful to public health workers interested in preventing fish tapeworm infections among the Eskimos of central and western Alaska. These peoples habitually consume raw or partially cooked fishes carrying the larvae of these tapeworms. In a recent study of enteric infections in the Bethel-Napaskiak area, Fournelle and Wallace (1958) found ova of Diphyllobothrium spp. in about 30 per cent of the human stool specimens examined, while a similar investigation by Rausch (unpublished data) at Hooper Bay in 1957 showed approximately the same rate of infection. Since it is generally suspected by medical investigators, both in this country and Europe, that tapeworms compete with their hosts for certain nutrients, such as vitamin B12, the development of a preventive measure which would destroy the larval cestode in fishes used as foods would be of particular value for the native peoples of western Alaska. This investigation included the following hosts and their helminth larvae: blackfish (Dallia pectoralis Bean), Diphyllobothrium dalliae Rausch and Triaenophorus sp.; whitefish (Coregonus lavaretus pidschian (Gmelin)), Diphyllobothrium sp.; red salmon (Oncorhynchus nerka (Walbaum)), Diphyllobothrium ursi Rausch; rainbow smelt (Osmerus dentex Steindachner), Diphyllobothrium osmeri von Linstow and Porrocaecum sp.; rainbow trout (Salmo gairdneri Richardson),