Home – Home – Jornals – Contemporary Problems of Ecology 2016 number 2

Dynаmics of the vendace of Lake Syamozero was monitored on the basis of the data collected for more than 75 years, and the evaluation of the present condition of the fish was given. The main biological parameters of the fish (body length and mass, gender, maturity, fecundity) were anаlyzed. The causes of the variations in the vendace number from year to year were considered.

Vendace ( Coregonus albula (L.)) is a very plastic species of freshwater whitefish which is widespread in Europe. But in Latvia this species is included into the list of specially protected fish species with limited use. We examined cross-species amplification of 14 microsatellite loci ( Cocl-Lav22, Cocl-Lav23, Cisco-59, Cisco-106, Cisco-90, Cisco-126, Cisco-157, Cisco-179, Cisco-181, Cisco-183, Cisco-200, BWF1, BWF2, and C4-183 ) which were successfully used for genetic studies, monitoring, protection and management of different Coregonus species. Five microsatellite markers ( BWF1, Cisco-90, Cisco-126, Cisco-157, Cisco-200 ) had a good representation in populations of vendace from five Latvian lakes (Sventes, Raznas, Nirzas, Dridzas, Stirnu) and were used for genetic analysis of these populations. It was shown that these 5 microsatellite loci were polymorphic and could differ among the investigated populations. The mean number of alleles per locus (from 4.4 to 6.2), the observed (from 0.53 to 0.70) and expected (from 0.49 to 0.70) heterozygosity, population structure ( F_ST and R_ST ) and gene flow ( Nm ) were also analysed in Latvian vendace populations.

Population-genetic study of five coregonid fish species dwelling in the Pechora River system was carried out using 30 enzyme loci. The studied species were: whitefish, a natural hybrid of vendace and least cisco, inconnu, peled and Arctic cisco. The investigation revealed rather low intraspecific genetic differentiation among the fishes of Lower Pechora and Usa River which is the main tributary in the Pechora River basin where coregonid fishes migrate to spawn. Presumably whitefish, vendace and inconnu, which inhabit the main channels of Lower Pechora River and Usa River, are represented by introgressive populations of species originated from a mix of discrete evolutionary lineages. Some lineages of whitefish, vendace and inconnu from the West Siberian periglacial lake had come to Eastern Europe together with peled, broad whitefish and Arctic cisco with the last migration wave from Western Siberia during the Middle Weichselian glaciation (60-50 thousand years ago), whereas in the Eastern European periglacial refugium (Lake Komi) local lineages of these species had survived. Lake Komi could have been located on the Pechora Plain since the Early Weichselian glaciation (90-80 thousand years ago), and the studied whitefish specimens of the Upper Pechora River are probably the “purest” descendants of the periglacial race of whitefish from Lake Komi. This supposition is supported by the data on the high level of genetic differentiation between the whitefish of Upper Pechora and Lower Pechora ( D_N = 0.005), as well as the pattern of allele distribution of some polymorphic loci. In our opinion, ecologic and genetic differentiation of vendace in the Pechora River basin is also connected with the interaction between two evolutionary lineages that originated from independent periglacial refugia.

Coregonus peled (Gmelin) (Teleostei: Salmoniformes: Coregonidae), which is considered an important object of coldwater aquaculture, had been successfully introduced into an enclosed Western Mongolian lake Ulaagchny Khar in the early 1980s. At the same time larvae of two other Coregonus species - Baikal omul C. migratorius (Georgi) and least cisco C. sardinella Valenciennes - had also been released into the lake. Baikal omul was then reported as a naturalized species. This might have caused interspecific hybridization and gene introgression. Identification of coregonids by morphology can be problematic, so to determine which species was dominant in the lake (we presumed it was peled) and if its gene pool was affected by other introduced Coregonus species we sampled 40 individuals and analyzed them by sequencing a fragment of mtDNA cyt b and by allozyme electrophoresis. The analysis showed that all the fish belonged to C. peled with no evidence of admixture from other coregonid species. Taking into account mass release of both species in 1980s, it is evident that naturalization of peled in the lake was much more successful than that of Baikal omul.

We studied the growth performance and liрid composition of liver, muscles and visceral fat in rainbow trout Parasalmo mykiss (Walbaum, 1792) and the diets used in its cultivation during the spring-summer season. The differences in dietary liрid composition determined modifications in the biochemical composition of tissues of rainbow trout and had an effect on the weight and growth rate of the fish. Trophic and seasonаl factors also had their influence on the studied parameters. The degree of influence depended on the functional characteristics of tissues and organs of rainbow trout.

The content of total liрids, total phospholiрids and fatty acids of total liрids in muscles and liver of juvelile Lake Baikal sympatric coregonid fishes were analysed for the first time under 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 liрids (phospholipids and cholesterol) dominated in total liрids of the tissues of all fish under study. Spare liрids significantly prevailed in omul muscles 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 3 polyunsaturated fatty acids in muscles of lacustrine whitefish and omul. Associations of liрid compositions revealed in tissues of the whitefishes under the study with their respective ecotypes have been discussed.

The base levels and seasonal variability of ethoxyresorufin-O-deethylase (EROD) activity, glutathione-S-transferase (GST) activity, reduced glutathione concentration (GSH) and phospholipids concentration (PhL) of Coregonus lavaretus (Linnаeus, 1758) and C. muksun (Pallas, 1814) were investigated. The relationships between this biochemical markers, hepatosomatic index and seasonal growth were also examined.

The correlation between the energy and carbohydrate metabolism rate with the length and weight of salmon ( Salmo salar L.) and whitefish ( Coregonus lavaretus L., C. albula L.) studied in nature, and farmed rainbow trout ( Parasalmo mykiss Walb.) was investigated. The results of the study showed that the largest and fastest-growing fish had high activity of enzymes involved in aerobic energy metabolism (cytochrome c -oxidase, malate dehydrogenase) and anаerobic metabolism (lactate dehydrogenase in muscles, 1-glycerophosphate and glucose-6-phosphate in liver). Age-related changes of the investigated parameters were caused by general reduction of aerobic metabolism rate and oxygen consumption during ontogenesis, increased lipid metabolism and the amount of stored substances. It was also shown that pubescent male and female whitefish (4+ and 5+) had differences in the correlation between enzyme activity of cytochrome c -oxidase 1-glycerophosphate and glucose-6-phosphate dehydrogenase and the length and weight of individuals.

The results of monitoring studies of the state of the common whitefish ( Coregonus lavaretus L.) inhabiting the Paatsjoki River and several lakes of Northern Fennoscandia were presented. The water-collecting area is contaminated with copper, nickel and sulfur dioxide due to airborne emissions of the “Pechenganickel” smelter. The ecological situation near the smelter is characterized as very unfavorable and requires constant control over the state of aquatic ecosystems. We used histopathology of gills, liver and kidneys as biomarkers to diagnose the condition of sparsely rakered whitefishes. The changes of cell structure in the fishes were diagnosed and classified. The revealed abnormalities were connected with the long-term exposure of the studied water bodies to airborne contamination. The possibility of using the obtained to evaluate the water quality was considered.

The structure and cytometric indices of red blood cells ( RBC ), hemoglobin content ( Hb ), oxygen capacity of blood ( OCB ) of the omul, whitefish and their hybrids from Lake Baikal and grown in the Freshwater Aquarium Complex ( FAC ) were analyzed. Cytometric indicators of red blood cells of omul and whitefish from natural populations were higher than that of the same fishes from aquariums under identical conditions. The conditions of aquariums had the least effect on the form of red blood cells of Siberian whitefish and hybrids: female Siberian whitefish and male omul F1 (f Sw ´ m Om). Female Lacustrine whitefishes, that had the largest erythrocytes, determined the size of the cells in hybrids: female Lacustrine whitefish and male omul (f Lw ´ m Om). Among all the studied forms of Coregonid fishes cytometric parameters of erythrocytes of the fishes from warm aquariums were higher than that of the fishes from cold aquariums. The size of the erythrocyte nucleus in artificially propagated hybrids was smaller both in comparison to their parents from natural populations and to whitefish and omul grown in aquariums under the same conditions. Erythrocytes of the whitefish from natural populations had a pool that was 20-30 % richer in functionally active mitochondria than that of the whitefish from aquariums. Disrupted mitochondrial structure was also observed in the latter. The obtained results indicate that the peculiarities of metabolism connected with oxygen transport in the studied forms of Baikal coregonids are determined by adaptation to the conditions of the occupied ecological niches.

Data on the infestation of certain fish species by the parasitic copepod Salmincola lavaretus are presented for the first time. The infested fish species included: Bauntovsky whitefish ( Coregonus baunti ), an endemic species from the Maloye and Bolshoye Kapylyushi Lakes; Siberian whitefish ( C. pidschian) and vendace ( C. sardinella) from the Bolshoye Kapylyushi Lake and the Baunt Lake which belong to the Tsypo-Tsypikan lake system (the Lena River basin, Transbaikalia); Teletsky whitefish ( C. lavaretus natio smitti ) from Teletskoe Lake (the Ob River basin). Previously, S. lavaretus had been described as a parasite of Baikal omul ( C. migratorius ) and Baikal whitefish ( C. baicalensis ) from Lake Baikal. The taxons of S. longimanus complex ( S. longimanus, S. l. sibirica, S. svetlanovi, S. lavaretus ) - parasites of nаsal fossae of grayling and coregonid fishes - were registered in the lakes of the Lake Baikal basin (Lake Baikal and Khovsgol Lake), the Lena River, the Yenisei and the Ob rivers (the largest rivers of the Arctic zoogeographic province) and the Kobdo River (the Western Mongolian province). It was assumed that S. longimanus complex is more widely distributed in the water bodies of the Arctic zoogeographic province of the Palearctic.