The composition of lipids and their fatty acids in white and red skeletal muscles, liver, hump, and gonads of the pink salmon Oncorhyncus gorbuscha (males and females) collected from three biotopes—marine, estuarine, and riverine—of the White Sea during spawning migration were studied. Changes in the lipid composition of the studied tissues chiefly maintain complex reproductive modifications (e.g., gonad maturation, spawning synchronization). The low proportion of arachidonic acid, 20:4n-6, in the gonads and white muscles of the fish collected in the riverine biotope indicated its selective catabolism, likely to synthesize prostaglandins involved in reproductive processes. The high proportion of stearic, 18:0, and docosapentaenoic acids, 22:5n-3, in muscles, liver, and oocytes testifies to their physiological significance in the process of female gonadal maturation. The site-specific changes in physiological active polyunsaturated fatty acids, namely, 20:4n-6, eicosapentaenoic, 20:5n-3, and docosahexaenoic, 22:6n-3, in white and red muscles, and the liver prove the involvement and importance of these fatty acids in the adaptations to changing environments (marine and fresh-water type of lifestyles) that salmon undergo during migration, gonadal maturation, and preparation for spawning. The functional significance of lipid remodelling processes in pink salmon during spawning migration to the riverine site was determined.

Margaritifera margaritifera is a critically threatened species in Europe. Metal pollution may be one of the reasons for its decline, but the influence of this factor remains insufficiently studied. Zn, Cu, Ni, Cd, and Pb were determined in the foot tissue of the freshwater pearl mussel Margaritifera margaritifera (bivalvia, margaritiferidae) from Green Belt rivers of Fennoscandia [the Murmansk region (Kola Peninsula) and Karelia (northern part)] and the accumulation of the metals was shown to be variable; however, their levels in the molluscs, being quite long-lived aquatic organisms, do not exceed the established standards of the Russian Federation. The recorded levels of the metals in the foot tissue of the Margaritifera margaritifera can be considered indicators of the background levels of geologic and anthropogenic metal concentrations in the environment influencing the distribution and development of this protected species in the lake-river systems of the Green Belt of Fennoscandia.

The pink salmon (Oncorhynchus gorbuscha) is a commercial anadromous fish species of the family Salmonidae. This species has a 2-year life cycle that distinguishes it from other salmonids. It includes the spawning migration from marine to freshwater environments, accompanied by significant physiological and biochemical adaptive changes in the body. This study reveals and describes variability in the blood plasma proteomes of female and male pink salmon collected from three biotopes—marine, estuarine and riverine—that the fish pass through in spawning migration. Identification and comparative analysis of blood plasma protein profiles were performed using proteomics and bioinformatic approaches. The blood proteomes of female and male spawners collected from different biotopes were qualitatively and quantitatively distinguished. Females differed primarily in proteins associated with reproductive system development (certain vitellogenin and choriogenin), lipid transport (fatty acid binding protein) and energy production (fructose 1,6-bisphosphatase), and males in proteins involved in blood coagulation (fibrinogen), immune response (lectins) and reproductive processes (vitellogenin). Differentially expressed sex-specific proteins were implicated in proteolysis (aminopeptidases), platelet activation (β- and γ-chain fibrinogen), cell growth and differentiation (a protein containing the TGF_BETA_2 domain) and lipid transport processes (vitellogenin and apolipoprotein). The results are of both fundamental and practical importance, adding to existing knowledge of the biochemical adaptations to spawning of pink salmon, a representative of economically important migratory fish species.

The freshwater pearl mussel Margaritifera margaritifera is considered to be the most rapidly declining species of freshwater bivalve, whereas its colonies in rivers of the White Sea Basin remain the most numerous in the world. The lipid profiles of mantle, muscle (foot), and digestive gland tissues of the freshwater pearl mussel from the Kem, Ukhta, and Vozhma Rivers in autumn (end of September, early October) were studied using high performance thin-layer chromatography. The highest total lipid [TL] content was found in the digestive gland. Cholesterol esters, non-esterified fatty acids, phospholipids, and cholesterol were the dominant lipids in all studied tissues. The reduced triacylglycerol content in the mussels was associated with its utilization during the spawning period. The colony of the freshwater pearl mussel inhabiting the Vozhma River was distinguished by higher TL content in the mantle and digestive gland. Data on the size-age characteristics of mollusks from the Kem, Ukhta, and Vozhma Rivers and the relationship between the structural and storage lipid content and size-age parameters are discussed. The results are important for different conservation strategies of endangered species, such as the freshwater pearl mussel, especially in ecological monitoring based on evaluation of the physiological and biochemical state of mollusks and rare natural colonies.

The freshwater pearl mussel Margaritifera margaritifera is a unionid species distributed across Northwestern Russia, Fennoscandia, Western and Southwestern Europe, and the Atlantic Coast of North America. In this study, we reconstructed the post-glacial expansion routes of this species based on FST genetic distances and the fact that M. margaritifera distribution is directly connected with salmonid expansion. The freshwater-pearl-mussel populations from North America and Northeastern Europe were the closest groups, judging by FST distances, supporting the concept of the North Atlantic Salmo salar colonization of the Barents and White Sea basins. We also documented that unique haplotypes in the populations of the Baltic and White Sea basins may have originated in isolated glacial refugia in Eastern and Northeastern Europe. The Iberian clade was the most distant group of populations, which is consistent with the previously observed role of the Iberian Peninsula as a glacial refugium. The high genetic diversity in the populations of Northern and Eastern Karelia was facilitated by migrants utilizing complex periglacial hydrological networks and by admixture in the contact zone where the migration flows met. We confirm that this region should be considered as a major center of genetic diversity within the European part of the species' range.

The article presents the results of approbation of the artificial nest-incubator of eggs "Salmo-3000" for the reproduction of salmon species of fish of the genus Salmo, tests were carried out in the r. Inder (White Seabasin). An original device was used, installed at the bottom of the river's threshold section. The nest design includes: the main body - a streamlined oval flattened container formed by three layered incubation trays and a lid; remote water intake / filter; connecting branch pipe with accessories for water distribution and discharge; elements fastening to the ground and a device for driving fasteners into the ground. The nest allows you to incubate fertilized eggs of Atlantic salmon or brown trout during autumn, winter and spring (autonomy for at least 8 months) and in summer (June) to obtain viable larvae that independently settle in the river threshold or are forcibly removed from rearing devices in the basins. During the test, the following advantages were revealed (increased capacity for incubated eggs up to 3,000 salmon / brown trout eggs per device, effective water distributor, grates that limit the eggs from washing out during laying, fixing rods made of fiberglass reinforcement that do not give oxidation, water intake / filter effectively cleaning and supplying water to caviar), and the disadvantage - the complexity and duration of the installation of the device, up to 60 minutes per device. In general, the hatching efficiency of larvae was 97.2% at partial load. The output of fry into the river was 96.0%. The device can be used to restore the abundance of Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.) in small rivers where hatchery reproduction is unprofitable for various reasons.

The conditions for cohabitation of juvenile Salmo salar and Margaritifera margaritifera in the River Kamennaya (River Kem catchment, White Sea drainage basin, Russia) were studied.The M. margaritifera population in the River Kamennaya contains about 1000 specimens.The only intermediate host capable of sustaining the existence of this rare North European mussel is the juvenile S. salar.In this study, we investigated a set of parameters and processes to get a more comprehensive insight into the ecology of the M. margaritifera.One of such parameters is the individual linear growth, which was investigated in freshwater mussels from the River Kamennaya.Growth deceleration coefficients varied widely and differed significantly among specimens.The population-averaged coefficient of growth deceleration was 0.076.The growth of mussels in the River Kamennaya involves three regular biorhythms with the following periods: 11.5, 6.4 and 4.0 years.The biorhythm periods were roughly constant both through an individual's ontogeny and among different individuals.A comparison of our results with data on other M. margaritifera populations in the Republic of Karelia and the Murmansk Region reveals a reliable (p < 0.01) negative correlation between growth deceleration coefficients and mean annual temperature in the M. margaritifera habitat.The abundance, spatial distribution and age structure of juvenile S. salar and M. margaritifera are presented.The rates of glochidial infection in S. salar juveniles at different ages were estimated.The developmental stages and the status of glochidia encysted on juvenile S. salar gills were observed and described using histological methods.The results of this study will be used to suggest activities and measures aimed to preserve populations of M. margaritifera and S. salar in the River Kamennaya, primarily to promote juvenile S. salar numbers and M. margaritifera settlement in rapids with a high density of young individuals.

The result of an extra factory method of reproduction of a chum (Oncorhynchus keta) is presented. The method is tested in small tributaries river Mulka (bass. The Sea of Okhotsk, Strait of Tartary) and in Savushkin's river (bass. Sea of Okhotsk, Second Kuril passage). The original devices representing the flattened container in which in 6 tiers incubatory modules with flutes for caviar are placed are used. The nest allows to incubate during the winter the impregnated caviar of salmon species of fish and to receive the durable larvae which are independently settled in a threshold of the river or forcibly taken from devices in pools in the spring. The device has the increased capacity for the incubated caviar to 10000 berries of a chum on the device, the volume method of loading of caviar in the device is applied, time of equipment and installation of a nest to the river doesn't exceed 15 minutes. In general efficiency of hatching of larvae has made 96%. An exit of larvae has averaged 42,5%. At insignificant completion the device can be used for restoration of number of a chum and other salmon species of fish in the small rivers where factory reproduction is for various reasons unprofitable.

The study focuses on the rheological behavior of a fluid based on a viscoelastic surfactant (Surfogel grade D, type 70-100, produced by JSC “Polyex”) in wide range of strain rates. This fluid is used for hydraulic fracturing technology as a proppant-carrying and proppant-retaining fluid in order to enhance oil recovery, including those with hard-to-recover oil and gas reserves. Quasi-static experiments to determine the values of the dynamic viscosity of the fluids under study were carried out using a falling ball viscometer (according to the Stokes method). The viscoelastic properties of fluids were studied using a Physica MCR501 rheometer with a cone-plane measuring system and an original rheometer with coaxial cylinders measuring system. The rheological properties of the fluid with the addition of proppant were studied using a Rheolab QS rheometer with a measuring system of the type of coaxial cylinders. The analysis of the rheological properties of fluids based on a viscoelastic surfactant has been carried out, and it has been established that fluids based on a viscoelastic surfactant has stable rheological properties over the entire range of strain rates, including fluid with proppant concentration up to 20%.

A multidisciplinary survey of three small rivers emptying to Lake Onego was carried out; information was collected regarding the aquatic biota, the species and age structure of riparian forests, their floristic diversity, and soils. The integral indicator chosen to assess the ecological condition of the watercourses was the characteristics of the rivers’ fish fauna, in particular fish of the Salmonidae family. Surveys of the rivers and riparian forest communities yielded records of 181 vascular plant species (11 of them macrophytes), 11 moss species, 2 lichen species; the fish fauna was made up of 9 species. Overall, the riparian forests featured a relatively wide range of typological diversity. The tree stands varied from the poor Ledum types (site class V) to the most productive Oxalis types (site classes III–I). Analysis of the tree species and age structure of forests in the riparian buffers revealed a prevalence of stable coniferous tree stands in good condition. Statistically reliable correlations were detected between the fish fauna and the tree species composition and inventory characteristics of the riparian forest stands, soil morphological characteristics, and the species diversity of the living ground cover and macrophytes. The species diversity of the riparian and the aquatic biotas were found to correlate positively with each other. Fish numbers were seen to negatively correlate with some characteristics of riparian forest soils (forest floor thickness, podzolic horizon), while the correlation with the humus horizon thickness was positive. Significant positive correlations were identified between aquatic organisms (fish, zoobenthos) and a majority of the stream’s hydrological parameters. The resultant up-to-date information about water-forest system components is important for understanding the role of small streams, which, alongside the scant officially recognized “spawning” rivers, are an ecological niche in the life cycle of salmonid fishes in Northwest Russia.

The laws governing the development of localization of plastic deformation under the conditions of manifestation of the effect of space-time heterogeneity (the Portevin-Le Chatelier effect) were investigated. Compression tests were carried out on cylindrical specimens of the aluminum alloy AMg6 with a constant strain rate of 0.4-1.7.10(-1) s(-1), inclined by 2 degrees from the vertical. This shape of the specimens determines a preferential direction for the formation of slip bands that allows for achieving large strains (up to 80%) without failure. Calorimetric studies of samples of the AMg6 alloy with varying degrees of deformation were carried out using a STA "Jupiter" 449 calorimeter. Statistical distributions of the intervals between the plastic flow stress fluctuations were analyzed and two critical points were found that indicate a change in the mechanisms of plastic deformation. The transition through the first critical point corresponds to the formation of multiple regions of localized plasticity. The further plastic flow of the studied alloy reveals multiscale signs of localization of plastic deformation over the rest of the plastic flow curve. At the stage of developed plastic flow, the maximum level of stored energy is observed during deformation. The transition through the second critical point is associated with the formation of nuclei of macroscopic failure, which is accompanied by the release of the stored strain energy and a decrease in calorimetric effects. The form of the probability density function of the intervals between the plastic flow stress fluctuations and the probability density function of the flow stress fluctuations confirm the self-similar nature of multiscale correlations of these quantities, similar to that observed for a closed turbulent flow of fluids between two rotating disks in the Karman experiment with large Reynolds numbers.

This work was inspired by works of Gianfranco D'Anna (2000) where the Portevin-Le Chatelier effect (PLC) was investigated by compressing Al-Mg alloy specimen in a very large deformation range and the results were interpreted from the viewpoint of phase transitions and critical phenomena. Two critical points where deformation process changes from "laminar" to jerky flow and back were noticed. We found that the second critical point where the rate of the serrations is decreased before the macroscopic fracture is not reachable for some alloys even with proposed geometry. We have tested 2 sets of specimens made of the same AMG6 alloy (-6% of magnesium) but with different amount of Si obtained from different producers. Specimens with a higher amount of Si tends to fracture before reaching the second point. Also, we have measured the amount of stored energy which can be recovered as heat during the annealing process. We used the differential scanning calorimeter STA "Jupiter" 449. We found that the amount of this energy sharply increases with the beginning of PLC serrations (first critical point) and drops at a second critical point or at macroscopic fracture. This can be related to a special type of critical phenomena structural scaling transitions in mesodefect ensembles and associated structural relaxation mechanisms Naimark (2016) 2019 The Authors. Published by Elsevier B.V.

It was found that each age group of young salmon has its own daily foraging activity pattern, mainly regulated by illumination. At the latitude of the Lizhma River (62°22ʹ40ʺ N, 34°29ʹ57ʺ E), which drains to Lake Onego, the foraging activity duration in June and July is 16 h ± 30 min. In twilight hours and in the dark (below 200 lx) it was absent in all age groups. Young-of-the-year (0+) maintained a constant level of foraging activityduring the day, making about 900 darts at food. Parr aged 1+ and 2+ foraged the most actively in the morning (18,000 lx), after which the activity declined until 15 h (70,000 lx)and remained low until 19 h (21,000 lx). Then it increased slightly until dusk. The number of darts at food was about 350 per day. For 3+ parr, the activity was the lowest in the morning hours, gradually growing afterwards to reach a peak at around 15 hours, after which a gradual decline was observed. During the day they make about 300 darts at food. The foraging intensity for 0+ fish averages 63 darts per hour. Fish aged 1+ make lessthan 30 darts/h; 2+ make about 40 darts/h; 3+ salmon make about 25 darts/h. Foraging activity can be reduced by dense clouds and competition. Young fish aged 0+ and 1+cannot compete with larger parr and other predators for fodder-rich sites. 2+ and 3+ parr occupy the most advantageous feeding microsites, where they perform up to 88 % of all daily darts for food in less than 50 % active time, and thus satisfy their daily nutritive demand. As a result, 2+ and 3+ parr would be more often seen inactive in “shelter” micrositescompared to 0+ and 1+ individuals.

The outcome of a non-hatchery method for chum salmon (Oncorhynchus keta) reproduction is presented. The method was tested in small tributaries to Malka River (Sea of Okhotsk catchment, Tatar Strait). Specially designed incubation nests were deployed on the bottom of river stretches with rapids. Each device is a streamlined flattened vessel with two layers of incubation plates with wells for individual egg. There is a water inlet in the bottom of the device to secure continuous supply of fresh water; water with embryos’ waste products is washed out of the device through an outlet tube on the top. The nest allows incubating fertilized chum salmon eggs during the winter and get viable larvae in spring, who would then either disperse across the rapid by themselves or be taken out of the devices to be post-reared in pools. The trial revealed both strengths(higher capacity for the incubated eggs –up to 404 chum salmon eggs per device, slots in the bottom of the wells preventing eggs from falling through to the underlying collection chamber during incubation but at the same time allowing the movement of larvae to the collection chamber after hatching) and structural flaws (poor water flow in the cassette installation mode, as well as flow blockage by sand clogging the water intake pipe). Overall, the hatching rate was 97.8 %. Not more than 48.7 % exited the next as larvae. Mortalities were partially due to the blockage of flow through the devices as a result of a critical drop in the water level during the winter low water period, and to the high sediment load, up to 25 cm. Losses were higher, in some devices up to 100 %, in the nests with cassette-type installation. After a minor upgrade, the device can be used to restore the numbers of chum salmon and other Pacific salmon species in small rivers.

The salmon spawning river Zolotitsa, its small tributary Paraninsky, and adjacent stream Lopatka were surveyed (11 sites in total) in Onezhskoye Pomorye National Park (White Sea drainage basin, joined to Kenozersky NP since 2016). The distribution of the Atlantic Salmon and conditions in its habitats were determined for the first time. The distribution densities of parr of different age categories were estimated. The average value was 59 fish/100 m2, which is above the average (50 fish/100 m2) across spawning rivers of Northwest Russia. The density of 0+ salmon varied among river sites from 13 to over 200 fish/100 m2 (August), and the rest of the population, with 25 fish/100 m2 average density in all 11 sites, was represented by older parr (1+, 2+, 3+). The biological characteristics of the river component of the Atlantic salmon population are given: ratios of different age classes, and length-weight parameters of the fish. Rapids in the river upper course were found to have a potentially insufficient juvenile salmon population. We suggest intensifying brooder protection during spawning migrations.

The surveys were carried out in OnezhskoyePomoryeNational Park, which in 2016 was joined to KenozerskyNational Park(Arkhangelsk Region). Four streams 6 to 13.6 kmlong were surveyed. The occurrence of the Salmo trutta in different areas across the watercourses and the habitat conditions were assessed. Juvenile and adult brown (resident) and sea (anadromous) trout aged 0+ to 6+ were detected. Data on the age composition of the trout are reported, the share of precocious males and the distribution density of juveniles of different age classes were determined for all the surveyed streams. The captures of precocious males and a precocious female confirm the high plasticity of the species in rivers emptying to theWhite Sea, which is manifest in the presence of both resident and sea-going individuals within the same population or reproductive group. The actions required to conserve and enlarge the trout population in streams of the national park include clarification of the timing and conditions of the spawning migration, investigation of the dynamics of the downstream migration of smolts, surveys of their abundance, as well as more intense protection of the watercourses.

Some aspects of the reproduction of salmonid fish in the small rivers Ol’khovka and Krivoy Ruchey (White Sea drainage basin, Tersky coast of the Kola peninsula), including downstream migration of brown trout and atlantic salmon smolts, as well as the distribution of juveniles of these species across these watercourses have been studied. Data are provided on the size-weight characteristics of the parr and smolts of both species, their sex and age composition. Correlation was revealed between the progress of downstreammigration and mean daily water temperature. It was established that small rivers with mean annual discharge below 1.5 m3/s harbor spawning of not only brown trout but also atlantic salmon. although the number of spawners is low (less than 20 pairs), this nevertheless contributes to enlargement of the species biodiversity. It should be borne in mind that there are hundreds of small rivers in the White Sea drainage basin, which collectively make a significant contribution to the abundance of both brown trout and atlantic salmon. The approach to surveys and studies of small watercourses should therefore be revised.

The activity level of calcium-dependent proteases of the calpain family in skeletal muscles of the atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.) from some watercourses (the Zolotitsa River and Lopatka stream) draining to the White Sea (arkhangelsk region) was estimated. a correlation between length-weight parameters of the fish and the rate of calcium-dependent proteolysis in their skeletal muscles was demonstrated. atlantic salmon parr from the Zolotitsa River were larger and had a higher growth rate compared to salmon of the same age from rivers of the Murmansk Region. The comparison of length-weight parameters and data on the rate of calcium-dependent proteolysisin brown trout parr from three watercourses draining to the White Sea and Lake Onegorev ealed the lowest growth rate in fish aged 3+, 4+ from the Lopatka stream. The obtained results indicate that the growth rate of salmonids S. salar and S. trutta depends on the environmental condition and availability of food resources in the studied waters.

Experimentally observed universality of fluctuation statistics in fully developed turbulent shear flow is linked to the dynamics of collective shear localization modes and new class of critical phenomenon of solid with defects structural-scaling transition. Universality appears as self-similarity of the distribution function of momentum power fluctuations on rotating discs (the Karman test) on the four orders of the Reynolds number that corresponds to the sharp power decay injected into the flow. Similar features of the coherent multiscale behavior established under multiscale plastic flow instability in AlMg alloy revealing the Portevin Le Chatelier effect. Localized shears could be considered as mesoscopic structural defects in liquids appearing due to the collective molecular slips.

This study was conducted to characterize the energy metabolism level and the features of muscle growth regulation during the development of Atlantic salmon (Salmo salar) inhabiting the Indera River (Kola Peninsula, Russia). The activities of aerobic and anaerobic enzymes (cytochrome c oxidase and lactate dehydrogenase) and carbohydrate metabolism enzymes (glucose-6-phosphate dehydrogenase, glycerol-3-phosphate dehydrogenase, and aldolase) were measured in muscle and liver tissue. Gene expression levels of myosin heavy chain (MyHC), myostatin (MSTN-1a), and myogenic regulatory factors (MRFs-MyoD1a, MyoD1b, MyoD1c, Myf5, myogenin) were measured in the white muscles of salmon parr of ages 0+, 1+, 2+, and 3+ and smolts of ages 2+ and 3+. Multidirectional changes in the activity of enzymes involved in aerobic and anaerobic energy metabolism with age were shown in the white muscles of the parr. The cytochrome c oxidase activity was higher in muscles of underyearlings (0+) and yearlings (1+) and decreased in 2+ and 3+ age groups. The activity of lactate dehydrogenase, in contrast, increased with age. The patterns of changes in expression levels of MyoD1a, MyoD1b, myogenin, MyHC, and MSTN-1a at different ages of the parr were similar. Particularly, the expression of these genes peaked in the yearling parr (1+) and then decreased in elder groups. The differences were revealed in parameters studied between the parr and smolts. The level of aerobic and anaerobic metabolism enzyme activities was higher in the white muscles of smolts than in parr. The activity of carbohydrate metabolism enzymes was decreased in the smolts' livers. The expression levels of MyHC, MyoD1a, MyoD1b, and myogenin were lower in smolts at age 2+ compared to parr. These findings expand our knowledge of age-related and stage-related features of energy metabolism and muscle development regulation in young Atlantic salmon in their natural habitat. The results might be used for monitoring of the salmon population during restoration and rearing.