Arctic Charr Salvelinus Alpinus Research Articles

Peculiarities of Early Ontogeny of Dwarf Forms of Arctic Charr Salvelinus alpinus Complex (Salmonidae) from Lakes Tokko and Bol’shoe Leprindo (Transbaikalia). 2. Reciprocal Hybrids

Peculiarities of Early Ontogeny of Dwarf Forms of Arctic Charr Salvelinus alpinus Complex (Salmonidae) from Lakes Tokko and Bol’shoe Leprindo (Transbaikalia). 2. Reciprocal Hybrids

Contrasting levels of sympatric divergence within lacustrine Arctic charr Salvelinus alpinus forms flock: high differentiation between size forms, low differentiation between seasonal races

Contrasting levels of sympatric divergence within lacustrine Arctic charr Salvelinus alpinus forms flock: high differentiation between size forms, low differentiation between seasonal races

Fine scale diversity in the lava: genetic and phenotypic diversity in small populations of Arctic charr Salvelinus alpinus.

A major goal in evolutionary biology is to understand the processes underlying phenotypic variation in nature. Commonly, studies have focused on large interconnected populations or populations found along strong environmental gradients. However, studies on small fragmented populations can give strong insight into evolutionary processes in relation to discrete ecological factors. Evolution in small populations is believed to be dominated by stochastic processes, but recent work shows that small populations can also display adaptive phenotypic variation, through for example plasticity and rapid adaptive evolution. Such evolution takes place even though there are strong signs of historical bottlenecks and genetic drift. Here we studied 24 small populations of the freshwater fish Arctic charr (Salvelinus alpinus) found in groundwater filled lava caves. Those populations were found within a few km2-area with no apparent water connections between them. We studied the relative contribution of neutral versus non-neutral evolutionary processes in shaping phenotypic divergence, by contrasting patterns of phenotypic and neutral genetic divergence across populations in relation to environmental measurements. This allowed us to model the proportion of phenotypic variance explained by the environment, taking in to account the observed neutral genetic structure. These populations originated from the nearby Lake Mývatn, and showed small population sizes with low genetic diversity. Phenotypic variation was mostly correlated with neutral genetic diversity with only a small environmental effect. Phenotypic diversity in these cave populations appears to be largely the product of neutral processes, fitting the classical evolutionary expectations. However, the fact that neutral processes did not explain fully the phenotypic patterns suggests that further studies can increase our understanding on how neutral evolutionary processes can interact with other forces of selection at early stages of divergence. The accessibility of these populations has provided the opportunity for long-term monitoring of individual fish, allowing tracking how the environment can influence phenotypic and genetic divergence for shaping and maintaining diversity in small populations. Such studies are important, especially in freshwater, as habitat alteration is commonly breaking populations into smaller units, which may or may not be viable.

Fatty acid profile of juvenile arctic char (Salvelinus alpinus complex) from natural ecosystems and aquaculture

Significant differences in the fatty acid composition of the muscle tissue of juvenile Arctic char Salvelinus alpinus [Linnaeus, 1758] from the natural habitat (Lake Sobachye) and aquaculture, as well as juveniles of the anadromous form of char (malma) Salvelinus malma [Walbaum, 1792] from the Avacha River. The observed differences between aquaculture and wild juvenile char were associated with different food sources. The muscle tissue of juvenile char from natural habitat was characterized by significantly higher levels of fatty acids – biomarkers of diatoms, as well as biomarkers of marine copepods in the anadromous form. In the fatty acid composition of juvenile char from aquaculture, significantly higher levels of linoleic acid were revealed, as well as long-chain monounsaturated acids, the source of which could be aquaculture feed. The identified differences did not have a significant effect on the content of eicosapentaenoic and docosahexaenoic acids in the muscle tissue of juvenile aquaculture and wild char. The content of biochemically valuable omega 3 polyunsaturated fatty acids in juvenile char from natural ecosystems and aquaculture was similar.

Abnormalities and Bilateral Asymmetry of Otoliths in Arctic Charr Salvelinus alpinus Complex (Salmonidae) from Lakes Lama and Kapchuk, Taimyr

Abnormalities and Bilateral Asymmetry of Otoliths in Arctic Charr Salvelinus alpinus Complex (Salmonidae) from Lakes Lama and Kapchuk, Taimyr

Experience of breeding char (genus Salvelinus) under industrial fish harvedy farming conditions

Of undoubted interest is the introduction into the aquaculture of the region of such a species native to the basins of the Kara and Laptev seas as the Arctic char Salvelinus alpinus (L.). A number of biological features of this species give special relevance to the prospects of the char as an object of aquaculture. The purpose of the work is experimental research and experience in breeding Arctic char using the example of the freshwater form of char on the Taimyr Peninsula. Information provided. Objectives: to study the conditions of keeping, feeding and growth characteristics of freshwater char when kept in cages on the Yenisei River. The object of the study was the freshwater form of char of the Taimyr Peninsula of generations 2021–2022. The study was carried out at two sites of Maltat LLC (Balahtinsky district of the Krasnoyarsk Territory, fish breeding farm in the city of Divnogorsk near the dam of the Krasnoyarsk hydroelectric power station) and at the Department of Breeding, Genetics, Biology and Aquatic Bioresources of the Federal State Budgetary Educational Institution of Higher Education Krasnoyarsk State Agrarian University. Environmental conditions, growth characteristics, growth rate and waste (mortality) were determined. When growing, granulated feed produced by Coppens were used. It has been shown that the weight of fish during cage rearing is higher than that of loaches from their native range. The growth rate of fish is minimal in January (about 2%), maximum in June-July. Freshwater char during cage cultivation on artificial feeds in the lower reaches of the Krasnoyarsk hydroelectric power station shows high weight growth characteristics exceeding those of fish from native habitats. Thus, research has confirmed the feasibility of factory reproduction of freshwater char from reservoirs of the Taimyr Peninsula in cages on the Yenisei River.

The role of temporal reproductive isolation, trophic polymorphism and growth rate fluctuations in the diversification of Arctic charr Salvelinus alpinus (L.) in Lake Kalarskii Davatchan, Transbaikalia, Russia

The role of temporal reproductive isolation, trophic polymorphism and growth rate fluctuations in the diversification of Arctic charr Salvelinus alpinus (L.) in Lake Kalarskii Davatchan, Transbaikalia, Russia

Density and biomass of Arctic charr Salvelinus alpinus (L.) complex (Salmoniformes, Salmonidae) from the two oligotrophic lakes at biotopes with different trophic levels

Density and biomass of Arctic charr Salvelinus alpinus (L.) complex (Salmoniformes, Salmonidae) from the two oligotrophic lakes at biotopes with different trophic levels

Fatty Acid Profile of Juvenile Arctic Char (Salvelinus alpinus Complex) from Natural Ecosystems and Aquaculture.

Significant differences in the fatty acid composition of the muscle tissue of juvenile Arctic char Salvelinus alpinus (Linnaeus, 1758) from the natural habitat (Lake Sobach'e) and aquaculture, as well as juveniles of the anadromous form of char (malma) Salvelinus malma (Walbaum, 1792) from the Avacha River were found. The observed differences between aquaculture and wild juvenile char were associated with different food sources. The muscle tissue of juvenile char from natural habitat was characterized by significantly higher levels of fatty acids-biomarkers of diatoms, as well as biomarkers of marine copepods in the anadromous form. In the fatty acid composition of juvenile char from aquaculture, significantly higher levels of linoleic acid were revealed, as well as long-chain monounsaturated acids, the source of which could be aquaculture feed. The identified differences did not have a significant effect on the content of eicosapentaenoic and docosahexaenoic acids in the muscle tissue of juvenile aquaculture and wild char. The content of biochemically valuable omega 3 polyunsaturated fatty acids in juvenile char from natural ecosystems and aquaculture was similar.

Peculiarities of Early Ontogeny of Dwarf Forms of Arctic Charr Salvelinus alpinus Сomplex (Salmonidae) from Lakes Tokko and Bol’shoe Leprindo (Transbaikalia). 1. Pure Forms

The results of the study of growth, ossification sequence and peculiarities of the development of skeletal elements, body proportions and meristic characters of laboratory-reared larvae and fry of two dwarf forms of Arctic charr Salvelinus alpinus сomplex spawning at the shore slope (Lake Tokko) and in the profundal zone (Lake Bol’shoe Leprindo) (Transbaikalia) are presented. Charr from Lake Bol’shoe Leprindo demonstrated slower rates of growth and morphogenesis, retardation of the ossification of their predorsal bones series with its displacement from larval to juvenile period of the ontogeny, but the acceleration of the development of the vertebral column. High mortality of pre-larvae of charr from this lake connected with the transfer to exogenous feeding was observed. For the first time the problem of the reorganization of early ontogeny of charr of the genus Salvelinus in connection with the colonization of deepwater habitat is discussed. In larvae of charr from Lake Tokko, the ossification of vertebral centra was often accompanied by the formation of anomalous bony structures in the notochord. The phenomenon of the penetration of skeletogenic cells into the notochord, which has been described in hybrids of sympatric charr forms, was found in a pure charr form for the first time. The development of characteristic morphological features of the two charr forms in the ontogeny was traced. Differences in body proportions between their fry corresponding to those between adult fish were revealed.

Extinction risks and threats facing the freshwater fishes of Britain

Abstract Extinctions occur naturally in all environments, but rates have accelerated rapidly during the Anthropocene, especially in fresh water. Despite supporting many fish species of conservation importance, there has never been a formal assessment of their extinction risks in Britain, which has impeded their inclusion in relevant legislation and policy. This study therefore used the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species™ Categories and Criteria to conduct the first systematic assessment of the extinction risks and threats facing the native freshwater and diadromous fishes of Britain. In addition, national assessments were produced for England, Scotland and Wales, reflecting the level at which environmental policy decisions are taken in Britain. Seven species were categorized as being threatened with extinction at the regional level, with European eel Anguilla anguilla and allis shad Alosa alosa classified as Critically Endangered, Atlantic salmon Salmo salar, vendace Coregonus albula and European whitefish Coregonus lavaretus classified as Endangered, and Arctic charr Salvelinus alpinus and twaite shad Alosa fallax classified as Vulnerable. In addition, burbot Lota lota was classified as Regionally Extinct, ferox trout Salmo ferox was categorized as Data Deficient, and 25 species were categorized as Least Concern. European sturgeon Acipenser sturio and houting Coregonus oxyrinchus, although probably native, qualified as only vagrants in fresh water, so were categorized as Not Applicable. The assessments provide objective baselines against which future changes can be determined, and a key evidence base to support policy and management decisions for the conservation of freshwater and diadromous fish species and their habitats in Britain. It is recommended that the assessments are repeated every 10 years, which would enable changes in conservation status, the effectiveness of policies and where targeted interventions may be required to be examined using the Red List Index.

Мониторинг стойких органических загрязнителей в промысловых рыбах Российской Арктики

The manuscript discusses the results of the analysis of persistent organic pollutants (POPs) in commercial fish species (atlantic salmon Salmo salar, rainbow smelt Osmerus dentex Steindachner et Kner, herring Clupea sp., arctic char Salvelinus alpinus) living in the waters of the Nenets Autonomous Okrug (NAO) and used in the diet nutrition of the inhabitants of the Russian Arctic. This study lays the foundation for monitoring of POPs, taking into accounts the possible risks and norms of daily consumption of traditional foods that affect human health in the Arctic. The authors determined the temporal trends in the content of POPs in Arctic fish species, as well as analyzed and compared published data on the content of POPs in traditional food. In the studied fish samples, p,p’-DDE, PCB 153 and hexachlorobenzene dominated among POPs, which corresponds to the trends in the accumulation of organic pollutants in Arctic hydrobionts. The total content of POPs in atlantic salmon, herring, arctic char and rainbow smelt was 15,01; 7,89; 2,38; 2,02 ng/g wet weight, respectively, which is tens to hundreds times lower than the established standard values. For all fish species, in the amount of at least 7 samples, the DDE/DDT ratio was high, which indicates early DDT contamination of fish habitats. Atlantic salmon and herring are the most contaminated fish species in the entire list of studied compounds. A decrease of POPs concentration in the studied fish species was noted in comparison with earlier studies conducted in similar areas. Despite the large amount of fish in the diet of peoples from the NAO, no significant risks have been identified. However, it was found that the level of PCBs in concentrations below the MPC carries a potential risk of cancer, especially with long-term consumption of atlantic salmon more than 45 g/day by the local population in one of the settlements of the NAO.

Elevated CO2 levels did not induce species- or tissue-specific damage in young-of-year salmonids.

The broad objective of our study was to use a histological approach to examine possible tissue-level effects of exposure to elevated CO2 in freshwater young-of-year salmonids. To study these effects, young-of-year Arctic Char Salvelinus alpinus, Rainbow Trout Oncorhynchus mykiss, and Brook Trout S. fontinalis were exposed to either control levels of CO2 (1400 μatm) or elevated levels of CO2 (5236 μatm) for 15 days. Fish were then sampled for gill, liver, and heart tissues and histologically analyzed. A species effect was observed for the length of secondary lamellae, as Arctic Char had significantly shorter secondary lamellae than the other species. No notable changes within the gills and livers of Arctic Char, Brook Trout, or Rainbow Trout exposed to elevated CO2 were observed. Generally, our results indicated that elevated CO2 levels over 15 days do not induce catastrophic tissue damage and it is unlikely that fish health would be seriously impacted. Ongoing research dedicated to examining how elevated CO2 long-term may affect internal tissues of fish will allow for a more comprehensive understanding of how fish may fair with ongoing climate change and in aquaculture facilities.

Behaviour and habitat use of first-time migrant Arctic charr: novel insights from a subarctic marine area

Anadromous Arctic charr Salvelinus alpinus is a cold-adapted salmonid that is vulnerable to climate warming and anthropogenic activities including salmon farming, hydropower regulation, and pollution, which poses a multiple-stressor scenario that influences or threatens populations. We studied the horizontal and vertical behaviour of Arctic charr tagged with acoustic transmitters (n = 45, mean fish length: 22 cm) in a pristine, subarctic marine area to provide insights into the behaviour of first-time migrants. Tagged fish spent up to 78 d at sea, with high marine survival (82% returned to their native watercourse). While at sea, they utilized mostly near-shore areas, up to 45 km away from their native river. Arctic charr showed large variation in migration distance (mean ± SD: 222 ± 174 km), and the migration distance increased with body size. Although the fish displayed a strong fidelity to surface waters (0-3 m), spatiotemporal variation in depth use was evident, with fish utilizing deeper depths during the day and in late July. These results represent baseline data on Arctic charr’s marine behaviour in a pristine fjord system and highlight the importance of near-shore surface water as feeding areas for first-time migrants. Furthermore, the observed dependency on coastal areas implies a vulnerability to increasing human-induced perturbations, on top of impacts by large-scale climate change in marine and freshwater habitats.

Differentiation of Arctic Charr Salvelinus alpinus Complex (Salmonidae) in Lakes Lama and Kapchuk (Taimyr) Based on Genetic Analysis, External Morphology, and Otolith Shape

The analysis of 17 microsatellite loci reveals five general forms of Arctic charr Salvelinus alpinus in large lakes Lama and Kapchuk (Norilo-Pyasinskaya water system, Taimyr) connected by the river. Three of them are represented by sister pairs, and, thus, eight reproductively isolated forms are defined. The immature individuals of different forms are hardly identified by external morphology. For the morphological differentiation of the five general forms, multivariate analyses of morphometric parameters of the body, otolith shape indices, and wavelet coefficients describing otolith contours are applied. All analyses show that goggle-eyed charr (“pucheglazka”) substantially differs from the other forms. The relationships between the four other general forms are variable depending on the method of analysis. Besides, a certain difference is observed in the data evaluating the left and right otolith shapes. The total correct jack-knifed classification of the forms in the linear discriminant analyses is 55.9% for morphometric indices and reaches 56.1 and 61.4% for the left and right otolith shapes assessed by wavelet transform. The overall morphological similarity of the forms can be explained by their parallel evolution in a restricted number of available trophic niches.

The vulnerability of Ireland's freshwater fish to climate change

Climate change can affect fish species directly (e.g. through physiological stress) or indirectly (e.g. species interactions). Whether individual species will experience net benefits or net losses is important to understand from a fisheries management perspective. Ireland has a unique freshwater fish community that faces considerable uncertainty in relation to the impact of climate change. Vulnerability of fish species and subspecies (n = 32) in Ireland were investigated through an expert-based questionnaire and a trait-based assessment. Fish species were assessed based on exposure, sensitivity and adaptive capacity. The expert-based questionnaire predicted that one species, Arctic char Salvelinus alpinus was assigned the rank of high vulnerability, seven species were assigned moderate to high vulnerability, twenty species were assigned moderate vulnerability, and four species were of low to moderate vulnerability. Life-history characteristics of the fish species were analysed to identify traits characteristic of vulnerable fish species (e.g. Vulnerability to fishing and Trophic level). Coldwater species are highly vulnerable, with indirect effects through interactions with other species or in combination with non-climatic stressors (e.g. water quality & barriers to migration) being a significant concern. The results provide a vulnerability ranking for Ireland's freshwater fish, that can be utilised by fisheries managers and allows for prioritising of an often-limited conservation resource.

Temporal stability of polymorphic Arctic charr parasite communities reflects sustained divergent trophic niches.

Polymorphic Arctic charr Salvelinus alpinus populations frequently display distinct differences in habitat use, diet, and parasite communities. Changes to the relative species densities and composition of the wider fish community have the potential to alter the habitat niche of sympatric Arctic charr populations. This study evaluated the temporal stability of the parasite community, diet, and stable isotopes (δ13C, δ15N) of three sympatric Arctic charr morphs (piscivore, benthivore, and planktivore) from Loch Rannoch, Scotland, in relation to changes to the fish community. All Arctic charr morphs displayed distinct differences in parasite communities, diet, and stable isotope signatures over time, despite the establishment of four new trophically transmitted parasite taxa, and increased fish and zooplankton consumption by the piscivorous and planktivore morphs, respectively. Native parasite prevalence also increased in all Arctic charr morphs. Overall, Loch Rannoch polymorphic Arctic charr morph populations have maintained their distinct trophic niches and parasite communities through time despite changes in the fish community. This result indicates that re-stocking a native fish species has the potential to induce shifts in the parasite community and diet of Arctic charr morphs.

Profound and rapid allopatric differentiation of Arctic charr Salvelinus alpinus on a microgeographic scale

Profound and rapid allopatric differentiation of Arctic charr Salvelinus alpinus on a microgeographic scale

Acoustic Telemetry Reveals the Complex Nature ofMixed‐StockFishing in Canada's Largest Arctic Char Commercial Fishery

AbstractClimate change is having a myriad of effects on Arctic ecosystems, yet understanding how these changes will influence the spatiotemporal dynamics of harvest in northern commercial fisheries remains unclear. Furthermore, stock mixing continues to complicate fisheries management in Arctic Canada, especially for anadromous stocks, but data on the extent and degree of stock mixing for the majority of northern fisheries are scarce. Here, we used a multiyear (2015–2019) acoustic telemetry data set to test the utility of acoustic telemetry as a potential tool for inferring stock mixing in the Arctic CharSalvelinus alpinuscommercial fishery in Cambridge Bay (Nunavut). We also assessed the effect of annual variation in environmental variables (river breakup and marine ice conditions) on the potential contribution of discrete stocks to commercial harvest at several fisheries. We found that stock mixing during the commercial harvest is common in both marine and freshwater fisheries during the summer/open‐water season, with virtually all stocks potentially being susceptible to harvest at any given commercial fishery. Additionally, in some fisheries, the vulnerability of different stocks to harvest was influenced by annual differences in marine ice and river breakup conditions. We discuss options for fisheries management, including a potential quota‐transfer system, and highlight how changing environmental and climatic conditions may have an effect on the commercial harvest of Arctic Char in the region. Overall, the results of this study demonstrate the utility of acoustic telemetry for informing mixed‐stock fisheries while highlighting the complex and pervasive nature of stock mixing in Canada's largest Arctic Char commercial fishery.

Bycatch of Loons Assessed in Coastal Arctic Char Fisheries in the Canadian Arctic

AbstractBycatch in fisheries remains one of the biggest conservation threats to seabirds globally, but there has been limited attention given to bycatch in the Arctic. Here, we worked with Inuit commercial fishers in the Cambridge Bay region of Nunavut to record bycatch of birds as part of a fish bycatch reporting initiative, in weir and gill‐net fisheries that target anadromous Arctic Char Salvelinus alpinus. Weir fisheries, and one of the gill‐net fisheries (executed in freshwater), had no bird bycatch, but 291 loons (family Gavidae) were captured over 5 years in one estuarine–marine fishery, yielding an exceptionally high bycatch rate of 15.7 birds/1,000 net‐meter‐days. One of the species caught, the yellow‐billed loon Gavia adamsii, is considered near threatened, but data on the population status of this species is insufficient to determine whether bycatch forms a significant threat. Nonetheless, deterrence efforts or other conservation options are needed in estuarine gill‐net fisheries to reduce bird bycatch.