Baikal Omul Research Articles

Nutrition of the Baikal seal and its role in the trophic structure of the Baikal ecosystem

The purpose of the work was to give as complete an overview as possible of the currently available publications related to the nutrition of the Baikal seal (Pusa sibirica).More than 50 sources devoted to the stated topic served as materials for writing the review.The results of the analysis of published sources showed that the Baikal seal feeds mainly on 4–6 species of small pelagic fish throughout the year, and the main food is two species of golomyankas of the Comephoridae family. The hypothesis according to which the well-being of the species is largely determined by the use of the pelagic crustacean Macrochectopus branickii for food does not stand up to criticism and is unlikely to reflect the real picture. The distribution of the Baikal omul is such that it does not exclude, but does not in any way contribute to the fact that the seal consumes it in significant quantities. However, the consumption of salmonids as food has become more frequent in recent years (the reasons for this cannot be established), but even now these fish constitute <3% of the biomass of fish consumed by the entire population of the Baikal seal per year. All adaptive morphophysiological, anatomical and behavioral features of the species clearly indicate that the seal has developed a food strategy aimed at the effective production and utilization of the above-mentioned fish species.Conclusion: the basis of the diet of the Baikal seal is made up of small non-commercial pelagic fish species, therefore, even with a large population, seals cannot be the reason for the reduction in commercial omul stocks.The practical significance of the work lies in the fact that its conclusions must be taken into account when developing rules and strategies for exploiting the Baikal seal population.

Ultrastructure of the mesonephros of whitefishes from the Lake Baikal basin.

The article presents a study of the mesonephros ultrastructure of Baikal omul Coregonus migratorius, Baikal whitefish Coregonus baicalensis, and a cross between Baikal whitefish and humpback whitefish (C. baicalensis × Coregonus pidschian). The mesonephros ultrastructure was studied using electron microscopy methods. The results of the study show that the number of mature granulocytes is a systematic feature and does not depend on the ecology of fish. The quantitative characteristics of blood cells and the ultrastructural features of leukocytes in the mesonephros are associated with the functioning of the nonspecific defence system in fish. Morphological diversity of epithelial cells in nephron tubules is the ancestral characteristic of the modern omul population, associated with geological and climatic events in the history of Lake Baikal. The development of haematopoietic tissue in the mesonephros, the ultrafine structure of ion-transporting interstitial cells, as well as some ultrastructural features found in the nephron, reflect the adaptive capabilities of the species to live in the ultra-deep Lake Baikal.

Assessment the state of the omul stock <I>Coregonus migratorius</I> in the waters of Northen Baikal according to hydroacoustic investigations

Recently in Lake Baikal there was observed decrease in population of the most abundant species among commercial fish – Baikal omul (Coregonus migratorius). That is why restrictive measures have been imposed on its catches. A hydroacoustic method based on hydroacoustic surveys was used to assess the evolution of the Omul population during the period of restrictive measures in one of the most productive fishery areas – the Northen Baikal. This work represented the results of three-year hydroacoustic research (2021, 2022 and 2023) in the first decade of June. Taking into account the confidence intervals for estimating the number and biomass of Omul, the stock in Northen Baikal is quite stable. The omul spatial distribution on the investigated areas is also stable.

Hydroacoustic studies of the structure of the Baikal omul feeding stock in the Selenga shallows of Lake Baikal

A comparative analysis of hydroacoustic data from 2011 to 2024 allowed us to determine the distribution characteristics of Baikal omul in the spring in the water area of the Selenga shallows under a significant decrease in stocks. Test trawling provided analysis of the length-at-age data on Baikal omul, revealed an increase in the stock abundance owing to the 2019-2023 generations, and confirmed the possibility of the correct use of the length-weight relationship (LWR), W=10.9(SLdm)3.02, based on long-term data. The obtained data predict a growth of biomass, as a more inert indicator, in four-six years. To formulate a more accurate forecast, it is necessary to adjust the natural mortality rates.

Исследование потребительских предпочтений в отношении традиционных продуктов питания (на примере туристов Байкальского региона)

Introduction. The article is devoted to the study of the consumption of traditional food products by tourists of the Baikal region. The study of the food traditions of different countries and regions of the world is an actual scientific topic. The field of gastronomic tourism has been actively developing in the recent years. The Baikal region is a unique region of Russia. The development of tourism in this region is possible through gastronomic tourism. It is known that traditional dishes play an important role in increasing the popularity of tourist destinations. In this regard, the purpose of this work is to study the consumer preferences for traditional food products (on the example of tourists from the Baikal region). Methods of research. For assessment of the satisfaction and consumer preferences of tourists in the Baikal region in relation to traditional food products, a questionnaire was developed (in Russian and English languages). During the study, 43 respondents were interviewed ― tourists of the Baikal region, permanently residing in other regions of Russia or foreign countries. Statistical processing of the results was carried out using standard methods of mathematical statistics. Results and its discussion. It has been found that buuzy, shulen, traditional green tea (nogoon sai), buchler are the most popular foods for the tourists of the Baikal region. The majority of respondents are satisfied with the quality of these products. At the same time, the study has shown that there is a list of traditional food products that the respondents haven’t tried during their stay in the Baikal region. For example, products from Baikal omul and products from wild-growing plants were tried only 79 % and 86 % of respondents respectively. Despite of this fact, the most of the surveyed tourists would like to purchase a fermented product from the Baikal omul. The most important consumer indicators of the quality of fermented Baikal omul are pleasant taste, reasonable price, pronounced aroma and health benefits. Conclusions. The majority of the respondents were satisfied with the quality of traditional food products of the Baikal region. Products from Baikal omul and fermented omul, in particular, were tasted only by a small percentage of respondents. It can be related to the fact that the commercial fishery was prohibited when the survey was conducted. Successful development of the Baikal fermented omul brand requires marketing support.

Гидроакустическая оценка запасов байкальского омуля (Coregonus migratorius) по результатам двухлетних исследований в весенне-летний период 2021 и 2022 годов

Taking into account the depressive condition of the Baikal omul resource, the decree of the Ministry of Agriculture of the Russian Federation No. 450 dated August 29, 2017 strict restrictions were established on the catch of Baikal omul in order to restore its reserves. Since 2021, a hydroacoustic method based on hydroacoustic surveys has been used to estimate its recovery. In 2021, on the fishing areas of Lake Baikal (Selenga shallow water and Northern Baikal) there were conducted surveys. In 2022, in addition to these areas, the researches were conducted in the Barguzin Bay and the Small Sea. Significant increase in the number of small omul was observed in the Selenginsky shallow water area in 2022. The results of a comparative analysis on Northern Baikal within the water area of 2021 showed that, taking into account confidence intervals, the number of omul and its biomass practically did not change. The averages omul biomass and number per unit area in the Small Sea were significantly lower than in the waters of the Selenginsky shallow water and the Northern Baikal. The lowest average densities were recorded in the Barguzin Bay.

Acoustic-trawl studies of the Coregonus migratorius (Georgi,1775) in the Selenga shallow water zone of Lake Baikal, 2023

Study of peculiarities of distribution of aggregations and size-age structure of the Baikal omul feeding stock in the Selenga shallow water zone of Lake Baikal were studied using the hydroacoustic method in combination with control trawls. Comparative analysis of the results of 2023 with the data of 2015-2022 showed significant changes in the general character of distribution of the Baikal omul aggregations in the water area and depth. Standard length of fish from different shallow water zones ranged from 10 to 39 cm with a sample median of 17 cm. In terms of weight, individuals of 18-26 cm in length were dominant. A “length-age” equation allows making an operational assessment of age class abundance correlation based on the probability of assigning individuals of a certain length to them. It is shown that 3-5 years old fish form the basis of the biomass of feeding stock in the Selenga fishing zone. A significant proportion of young fish indicates that there is sufficient recruitment to increase the biomass of the Baikal omul stock in 5 years perspective.

Эколого-морфологическая характеристика нерестового стада посольской популяции байкальского омуля Coregonus migratorius Georgi в современный период (по данным 2009–2020 гг.)

The timing of the start and end of the spawning migration of the Baikal omul is specific for each of its populations, is closely related to the temperature regime in their areals and fluctuates from year to year in accordance with the variability of climatic conditions in the basin of the lake. Since the thermal and water regime of Lake Baikal is changing under the influence of global warming, the omul populations are adapting to shifts in the rhythms of the functioning of the lake's ecosystem. The purpose of this work is to analyze changes in the current ecological and morphological composition of spawning stocks of omul on the example of the posolskaya population in connection with the recorded changes in the timing of its migration for spawning in the 2000s. To analyze the nature of the variability in the timing and dynamics of spawning migration in 2009–2019, we used data from calendar records of the catch by a fixed river seine of mature individuals entering spawning rivers – tributaries of Posolsky Sor Bay. For ecological and morphological analysis, we used data on the morphometry of the omul that entered the Bolshaya Rechka River (one of the main tributaries of the Posolsky Sor. Bay) in different periods of the spawning season of 2020. The results of measurements of spawning migrants in 2020 indicate that, against the background of a general delay in the timing of migration, the dynamics of the morpho-ecological composition of spawning shoals is identical to that in the 1960s and 1980s and is typical for the population under the study. At the same time, data on the morphometry of fish that entered the river in different periods of the spawning season of 2020 indicates a change in the ecological and morphological structure of the population, namely, the quantitative ratio of spawning migrants from various subpopulations changes towards the predominance of "pelagic predators" – inhabitants of the deep-sea areas of Lake Baikal.

Results of resource hydroacoustic surveys of the Baikal omul in the fishing waters of Lake Baikal in the spring-summer period of 2022

The purpose of the work carried out is to quantify the abundance of the Baikal omul within the four fishing areas of Lake Baikal (Selenginsky shallow water, Northern Baikal, the Small Sea, Barguzin Bay), to build maps of the spatial distribution of fish concentrations in the surveyed waters.The data collection and processing method is based on hydroacoustic survey, during which echo signals are recorded in the vertical direction along the route of the ship along a pre-planned transects. To calculate the values of surface densities along the survey transects, the echo integration method was used. When calculating surface density values, data from control catches are used. The Kriging geostatistical interpolator was used to numerically estimate the stocks of omul and its distribution within the surveyed water areas.New data have showed that in the main fishing area of Lake Baikal, the Selenginsky shallow water, there was a high abundance of juvenile omul, less than 22 cm in size of the 2018 generation and younger. In the areas of the Small Sea and the Barguzin Bay, no significant accumulations of fish were recorded. In Northern Baikal, the abundance and biomass of the omul was comparable to the results of 2021.The practical significance of the research results is the quantitative assessment of the omul stocks and its distribution in the fishing areas of Lake Baikal in order to predict its stocks.

MATERIALS FOR THE RECOMMENDATIONS ON PRE-SPHERING MAINTENANCE, NATURAL SPRINGING OF THE BAIKAL OMUL IN THE SELENGA RIVER FOR THE PURPOSE OF ARTIFICIAL REPRODUCTION IN 2020

This paper presents data on the collection, analysis, processing of materials for keeping spawners of the Baikal omul, determining the optimal stocking density of fish in cages, determining the efficiency of using spawners in 2020.

Unexpected Discovery of an Ectoparasitic Invasion First Detected in the Baikal Coregonid Fish Population

The omul, Coregonus migratorius (Georgi, 1775), an endemic fish of Lake Baikal, is the main commercial species of essential economic importance for the extensive region of Eastern Siberia. Despite the continuous 250-year study of Baikal omul and intensive commercial fishing, neither fishers nor biologists have ever mentioned or found external annelid parasites in numerous omul catches. Targeted parasitological studies have also never detected these ectoparasites on the body of this fish. In this study, we present the first reliable information on the existence of specific annelid parasites infecting the pelagic population of Baikal omul and report a 4% infestation of spawners in the Selenga River, the largest tributary of Lake Baikal. We also obtained the main morphometric parameters of the infected fishes, the morphology of the unknown parasite and its feeding strategy. DNA-based analysis was applied to ascertain the taxonomy of the leeches and revealed no closely related taxa existing in international genetic databases (e.g., GenBank) to date. A maximum genetic identity of 89–91% was detected with European Caspiobdella fadejewi. The genetic distances in 9–11% of the substitutions from the closest relatives were very high for a reliable molecular identification of a taxon. The Selenga omul leech may represent a potentially new species and genus.

Изучение микробиологических показателей ферментированного байкальского омуля, изготовленного с применением молочнокислых бактерий

The work is devoted to the study of the effect of the fermentation process on the microflora composition of fermented product from the Baikal omul (Coregonus migratorius (Georgi, 1775)), produced with the use of bacterial concentrate of lactic acid bacteria Latilactobacillus sakei ((Katagiri et al. 1934) Zheng et al. 2020). It has been established that, according to microbiological indicators, fermented Baikal omul meets the requirements of regulatory documentation. The microflora of the control (without the use of bacterial preparations) and experimental (with the use of a bacterial concentrate of lactic acid bacteria) batches had significant differences.

Morphological characteristics of fins of the Baikal omul’s spawning herd Coregonus migratorius (Georgi) of three morpho-ecological groups

A comparative characteristic of the meristic and plastic features of the fins of the spawning part of the population of three morpho-ecological groups (coastal, bottom-deep and pelagic zones) of the Baikal omul, which are in a depressed state, is given. In the bottom-deepwater and coastal MEG, in relation to the pelagic MEG, the greatest difference in dimension is noted in such features as: the height of the dorsal fin (by 2.14% l Sm), the height of the anal fin (by 1.5% l Sm), the length of the caudal stems (by an average of 2.17% l Sm), the length of the abdominal and pectoral fins (in average 1.64% l Sm). The difference in the length of the base of the anal (0.17% l Sm) and dorsal fins (0.49% l Sm) is less pronounced. Thus, the greatest differences in dimension are noted in the height of the dorsal, anal fins, the length of the pectoral, ventral fins and caudal stems. The difference in the length of the base of the anal and dorsal fins is less pronounced. During the period of anthropogenic load, there is no obvious, significant variability of morphological signs associated with the movement of fish of the Baikal omul. Sexual dimorphism is traced. In males, the indices of the signs of the studied fins are greater than in females by an average of 0.7% of the length according to Smith. A greater limit value of soft rays is observed in bottom-dwelling fish in the abdominal (up to 15 pcs.) and anal (up to 14 pcs.) fins, while in pelagic up to 12 soft rays in the compared fins. In bottom-dwelling fish, a greater number of soft rays are noted in the abdominal and anal fins, which are responsible for fish stabilization, rapid ascent in the vertical plane, rotation and abrupt stop.

Length‐weight relationships of Baikal omul <i>Coregonus migratorius</i> during the feeding season in the Selenga area, Russia

Aim . To refine the LWR coefficients for the Baikal omul Coregonus migratorius (Georgi, 1775). Material and Methods . The data set (number of fish, standard length ( SL ), weight ( W ), sex and morpho‐ecological group (MEG) for the study of the LWR coefficients were taken from the Baikal Omul database. The analysis includes data from 3,091 specimens of Baikal omul, collected in May to June 2003, 2006 and 2007 and in September 2004 in the area adjacent to the delta of the Selenga River. The construction of regression models of LWR was carried out for all data without taking into account gender and MEG. In addition, regression models of LWR data were obtained, grouped by gender and belonging to a certain MEG. Results . Dependencies with close values of the coefficients of the power function are obtained. There were no significant differences between fish of different sexes and MEG, the coefficients differing at the level of statistical error. It is shown that the LWR in fish during feeding periods of different years is quite stable. Conclusion . We offer the equation W=10,9(SL dm ) 3.02 that has acceptable coefficients for C. migratorius resource estimations during feeding period without carrying out controlled fishing.

Assessment of PCBs in Surface Waters at Ultratrace Levels: Traditional Approaches and Biomonitoring (Lake Baikal, Russia)

This article presents the results of the assessment of PCB concentrations in surface waters at ultratrace level of concentrations. The assessment of PCB concentrations is based on data from monitoring PCBs in Baikal water within the conventional approach as well as from biomonitoring of PCBs using Baikal omul, Coregonus migratorius, Georgi, 1775 (C. migratorius), as a bioindicator. The time cycle of the monitoring covered the period from 2014 to 2021. The concentrations of PCBs in the water were estimated from the concentrations of seven indicator congeners: 28, 52, 101, 118, 138, 153, and 180, and from congeners of dioxin-like (dl) PCBs in the tissues of C. migratorius. The average value and the statistically significant range of the detected total concentrations (Ʃ7PCBs) in Baikal water were 0.30 and 0.26–0.34 ng/L, respectively. In the tissues of C. migratorius, the average value and the range of Ʃ7PCB concentrations were 5.6 and 4.9–6.3 ng/g (ww), respectively, and for dl-PCBs, 1.5 and 1.3–1.7 ng/g (ww), respectively. The total toxicity equivalent of the detected dl-PCBs was in the WHO-TEQ (2005) range from 0.03 to 0.06 pg/g (ww). The concentrations of Ʃ7PCBs in Baikal water and dl-PCBs in the tissues of C. migratorius corresponded to the concentration levels in the European alpine lakes and the tissues of S. trutta fish inhabiting these lakes.

Long-term dynamics of the parasitological situation in the Baikal omul in the Chivyrkuisky bay of Lake Baikal

Long-term dynamics of the parasitological situation in the Baikal omul in the Chivyrkuisky bay of Lake Baikal

Исследования влияния расхода воды на протяжённость нерестовой миграции байкальского омуля Coregonus migratorius (Coregonidae) в реке Селенге на базе многолетних данных

The Selenga River, the main tributary of Lake Baikal, is 1,453 km long and accounts for 50 % of its surface runoff. It is a large foothill, free-flowing, unregulated watercourse flowing through Mongolia (2/3 of the length) and Russia (1/3). Global climatic changes in recent decades have been particularly evident in the Baikal region: since the mid-1990s, there has been a significant decrease in water and sediment runoff in the Selenga basin. Omul spends most of its life cycle in the lake; spawning takes place in the river system. In total, there are 22 spawning rivers of Baikal omul in the Lake Baikal basin, among which 47 % of its spawning grounds are concentrated in Selenga. Omul spawns in the Selenga channel within 20–580 km upstream of the lake, and in some years it crosses the border between Russia and Mongolia. Based on long-term (1936–2018) data of the Baikal omul spawning migration in the Selenga River, the relationship between the average migration distance of the spawning herd core and the water discharge at the beginning of the spawning migration (September) was analyzed. Statistical analysis has established an approximate threshold for water discharge, which marks the shortening of the spawning path in «high-water» years and a noticeable extension of it upstream in “low-water” years. The role of other cumulative factors affecting the spawning distance of omul is discussed. Under conditions of a long subglacial period, omul eggs are successfully incubated in large areas for five to six months (November–April). Stability of habitat characteristics in such a shelter is ensured by a significant decrease in flow velocity and temperature, as well as increased water transparency and a relatively favorable oxygen regime. Ice cover formation can also be attributed to protective factors: it reliably shelters eggs from external atmospheric impact: average ice thickness on the river during the study period was 0,5 m (0,1–1,5 m, maximum by spring it often reaches 2 m near the shores). Hydraulic construction in the upper Selenga Watershed in Mongolia could have a significant negative impact on the spawning grounds of the Baikal omul, reducing the survival of its eggs during the winter months. Such impacts, combined with global warming and other anthropogenic disturbances, may even lead to the extinction of this cold-loving endemic of the Selenga Basin, which will undoubtedly affect the entire lake ecosystem.

Estimation of the Bay Proval Volumein Lake Baikal Using the QGIS and the SAGA GIS Geographic Information Systems

The research estimated the water surface area and volume of the fishing bay Proval in Lake Baikal by using the QGIS and SAGA geographic information systems. Such characteristics are used by ichthyologists to assess the reception capacity of the water area. Additionally, we considered the cases when the water level drops by 0.6 and 1.2 meters. The results may be used to predict population size of Baikal omul in low-water periods.

Comparative morphological characteristics of spawning populations of Baikal omul (Coregonus migratorius, G.) in the Posolsky Sor, Selenga and Barguzin rivers

The morphological structure, size-age variability and dynamics of age-related fertility of producers of Baikal omul of pelagic, near-bottom and coastal morpho-ecological groups during the depressive state of the population were studied. There is an improvement in the indicators of the growth rate of fish, maturation and an increase in absolute individual fertility against the background of the dilution of the population and the release of the feeding area. A comparative characteristic of some morphological features of fish among morphological-ecological groups is given. The number of gill rakers on the first gill arch significantly distinguishes different morpho-ecological groups and ranges from 36 to 43 pieces for the near-bottom, from 40 to 46 pieces for the coastal and from 44 to 53 pieces for the pelagic morpho-ecological groups. It is noted that the spawning populations of the coastal and pelagic groups are mainly represented by young individuals. With age, the proportion of females increases in all groups. The largest indices of the pectoral, abdominal and anal fins, responsible for movement in the vertical plane, rotation and stop, are noted in the near-bottom group.

Influence of abiotic factors on incubation of Baikal omul eggs in the Selenga River (Lake Baikal Basin)

Abiotic factors affecting the choice of spawning sites for the Baikal omul (Coregonus migratorius) in the Selenga River over 27 years were studied. A total of 3,450 samples were collected using the Dulkeit scraper in Decembers of 1987-2014, at 24 trans-sections in the Selenga River channel over a total length of 410 km. At each sampling site we recorded omul egg density, substrate particle size, water depth, water flow velocity, and ice thickness. Omul eggs were found mainly on hard substrates (sand, gravel, pebbles, and pebble-cobbles combinations). Omul has been found to avoid spawning at depths less than 1.5 m and greater than 6.0 m. Water velocity and ice thickness did not strongly influence the choice of site. Omul eggs were found at flow rates of 0.05-0.7 m/s with a maximum at 0.1 m/s.