Fishing industry in the Irkutsk Region: resource potential, development, current situation

. The major natural reserves of inland water resources in the Russian Federation have high fishing value and allow large-scale fishing activities. One of the regions where these water resources are localized is the Irkutsk Region. Within its borders there are parts of the largest Baikal-Angarsk and Verkhnelensk water basins with a very developed river network, with reservoirs and lakes, where dozens of fish species live in natural conditions, including those of industrial importance. This article provides a brief overview of the structure and reserves of the water resources, their distribution over the territory of the Irkutsk Region. The main fishing areas are specified and the assessment regarding their fishing potential and commercial stocks is made. An overview of the fishing potential of the Irkutsk water area of Lake Baikal and large reservoirs of the Angara cascade of hydroelectric power plants is given. The history of the development of fishing industry in the region is demonstrated. The article concludes that in the water bodies of the region there are stocks of commercial fish species, which are currently poorly developed or almost not used (being practically untouched in natural conditions). The poor development is due to both natural and climatic and economic and geographical reasons.


Introduction
The Russian Federation has vast areas of inland freshwater bodies for industrial fishing with a total area of 295 thousand sq km (the lakes account for 76.3%, the reservoirs do for 23.7%). The length of the rivers for fishing industry in Russia is about 500 thousand km. Commercial fish stocks in inland waters allow for rationally permissible and economically efficient fish catch exceeding 200 thousand tons per year. The actual catch in the 1980-ies was estimated at 160-180 thousand tons; in the early 2000-ies the catch was almost two times lower than the possibility, which was reflected in the annually approved rates for the total allowable catch (TAC), which ranged from 100 to 120 thousand tons.
The Irkutsk region accounts for about 8% of the fishing water bodies' area in Russia. The resource potential of these fishing water bodies is almost fully built due to the natural reproduction of fish, which makes it possible to have an allowable fish catch ranging from 2.4 to 4.0 thousand tons of fish per year that is 1-2% of the all-Russian fish catch. The actual fish catch (including recreational fishing) is 0.6-1.0 thousand tons, or less than 1% of the all-Russian fish catch in all the inland freshwater fishing water bodies in Russia.
The relatively low shares in the all-Russian fish catch are due to several reasons. The main one is the fact that the majority of rivers, lakes and reservoirs are located in the remote areas of the Irkutsk region, therefore, more than 65% of the potential fishing water bodies are not developed. The second reason is connected with the low productivity of the fishing water bodies in comparison with some other Russian fishing areas, where the climate is more temperate. The climate in the Irkutsk region is sharply continental with the average annual temperatures ranging from minus 0.5 degrees Celsius in the southern areas to minus 11.0 degrees Celsius in the northern ones. Finally, the third reason is the disadvantageous qualitative parameters of the species range of fish in small and medium-sized water bodies and rivers, where small, stunted species with low marketable indicators prevail.
Let us consider the fishing industry potential of the Irkutsk region in more detail.

Materials and Methods
The current research uses statistical data on the issues under consideration received by the Territorial Body of the Federal State Statistics Service for the Irkutsk region "Irkutskstat"; proceedings of the Territorial integrated scheme for the development of productive powers in the basin of Lake Baikal [Moscow, State Institute of City Planning, 1989], data from the Strategy of socio-economic development of the Irkutsk region until 2030; environmental monitoring data (State Report "On the State of Lake Baikal and Measures for its Protection in 2019"), reporting data of the territorial administration of the Federal Fisheries Agency, as well as data received at the request of the authors from the state authorities, local government and public organizations. In addition, the article is based on the previous research including the expeditionary research carried out by the Institute of Economics and Industrial Engineering of the Siberian Branch of the Russian Academy of Sciences and the Limnological Institute of the Siberian Branch of the Russian Academy of Sciences. The data received have been summarized and analyzed by the authors, and discussed at a number of scientific seminars and with the core group of amateur fishermen.

Water bodies
The Irkutsk region is located in Eastern Siberia, almost in the geographical centre of Asia, west of Lake Baikal. Its area is 775.1 thousand sq km (it is the sixth largest among the constituent entities of the Russian Federation) or 4.5% of Russia's territory.
There are enormous reserves of river and lake water within the region. There are over 60,000 rivers, streams and creeks, totaling 310,000 km (i.e. eight equatorial circles of the earth). The average density of the river network is 400 meters per 1 sq km. The average long-term river flow is estimated to be 7.5 thousand cubic meters per second (160-240 cubic km per year). The river network includes the headwaters of the major rivers of North Asia, such as the Angara river (the largest tributary of the Yenisei river), the Lower Tunguska river, the Lena river, and their numerous tributaries (Table 1). Due to the abundance of water and special hydrological regime, many rivers are of interest for hydropower construction. Some of them (the Angara river and the Mamakan river) have already been used to build hydroelectric power plants and large artificial reservoirs.
The south-eastern part of the Irkutsk region runs along Lake Baikal for several hundred kilometres, covering 23% of its water area. In addition to Lake Baikal, there are about 4,000 small and medium-sized lakes within the Irkutsk region, about 200 of which are potentially suitable for sport and recreational fishing.
There are several large reservoirs formed during the construction of the hydroelectric power plants, i.e., the Bratsk hydroelectric power plant, the Ust'-Ilimsk hydroelectric power plant, the Boguchansk hydroelectric power plant, the Irkutsk hydroelectric power plant and the Mamakan hydroelectric power plant ( Table 2). The total area of these reservoirs is 7,919 sq km and the volume of water is 242.5 cubic km. The huge number of rivers and lakes and the presence of several large reservoirs have contributed to the species diversity of the water bioresources. About 60 fish species, including valuable and commercially valuable ones (omul, sturgeon, grayling, whitefish, burbot, pike, perch, etc.), live in the region's water bodies.

Fishing industry development in the Irkutsk region
The fishing industry is one of the oldest in the Baikal region. Its development began in the 17th century, simultaneously with the economic development of the territory of the region; it was based on the fish resources available in the water bodies and was connected with satisfying the population's nutritional needs. At the beginning of the development of Siberia, the rivers and reservoirs of the region were rich in fish, and catching it was easy and was carried out with some primitive equipment. Therefore, fishing was practiced everywhere. It contributed to the households, especially in the northern areas where there were few lands suitable for agricultural development. At the initial stages of the economic development of the region, fish was caught and processed only for the local consumption. As the region developed economically, fishing became more market-oriented. At the time, fishing was based on unexploited fish stocks and was very profitable.
The fish was supplied to domestic and foreign markets mainly as salted fish, and in winter it was frozen. The salting method was simple: the fish was gutted, filled with salt and placed in rows in special vats, with each layer covered with salt again. There was also a method of souring (fermenting) fish. In addition, some species of fish were smoked, dehydrated and dried in the sun in summer. Larger fish were used to make the so-called pozema (a type of cured fish), which was roasted over a fire after being cured. Caviar of large fish was salted.
Starting in the 17 th century small artels consisting of 5-15 people were engaged in fishing. During the second half of the 20 th century there appeared private industrial fishermen who hired fishing workers, mainly from the local population, for the period of fishing. Such workers were paid from 20 up to 100 rubles (or 80-400 US dollars at the year of 1900 prices).
At Lake Baikal fishing became very market-oriented, here it was not only the coastal territory of the lake, but also that one of the spawning rivers flowing into it, where they caught and then processed fish. Fishing was of less importance on the Angara river and its tributaries. Here fishing and preserving the fish caught was a complementary activity aimed at satisfying the local needs. In the basin of the Lena river the development of the fishing industry was due to the rapid development of the gold-mining industry in the Lena-Vitim gold field and the growing demand for food, associated with it.
Fishing methods in those years ranged from seine nets and nets to simple fishing rods. The commercial species were sturgeon, sterlet, omul, whitefish, grayling, lenok, taimen, pike, saffron cod (roach), burbot and perch. Sturgeon, taimen and omul were especially valued.
By the beginning of the 20 th century dozens of leading industrialists were engaged in catching and preserving fish, the number of fishing workers reached several thousand. The fishing fleet consisted mainly of small sailing (later steam) vessels, and the fish processing industry was represented by semi-handicraft production facilities for salting and smoking fish.
The development of the steamship line and the construction of the Trans-Siberian railway strengthened the commercial nature of the fishing industry. The fish trade began to play a prominent role in the internal economic relations of the Irkutsk province. At the beginning of the 20 th century about 700 tons of fish were caught in the waters of the Irkutsk region. Within the borders of the Irkutsk Governorate-General, covering at that time the modern Krasnoyarsk Territory, the Sakha (Yakutia) Republic and the whole of the Transbaikal Region, over 8,000 tons of fish were caught, at a total cost of about 100,000 rubles (about 400,000 US dollars at the year of 1900 prices). The basin of Lake Baikal (including the Selenga river, the Barguzin river and other rivers) accounted for 2-3 thousand tons.
Part of the fish catch was used for local consumption, while some was transported to cities and towns as well as to the Trans-Siberian railway by water and horse-drawn carts. The fish caught was shipped by rail (the fish was raw, frozen and salted) to other regions of Russia.
Industrial fishing in the basin of Lake Baikal developed facing stiff competition from the neighbouring fish-rich basins, i.e. the Amur and Pacific basins in the east, the Yenisei, Ob and Volga-Caspian basins in the west.
During the Revolution and the Civil War During the war and post-war years, with food shortages, the regional fishing industry became nationally important. At that time, the fish production within the borders of today's Irkutsk region reached its all-time high of over 5,000 tons.
Large-scale fishing, especially during the spawning season at Lake Baikal in the riverbeds of its tributaries undermined the stocks of the most valuable, delicacy Baikal fish, i.e. sturgeon and omul. By the early 1960-ies, the stocks of almost all commercial species were severely depleted. At the same time, a large-scale hydropower construction began on the Angara river. Powerful hydroelectric power plants and three large reservoirs were built. Due to this the level of Lake Baikal rose by more than 1 meter, and the hydrological, hydrochemical and biological characteristics of the Angara river significantly changed: the current disappeared, the depths increased; this changed the composition of the ichthyofauna. With the placement of powerful logging, pulp and paper, metallurgical, petrochemical enterprises and plants in the region and the growth of the cities, the pollution of the water bodies increased, which also reduced the fish productivity of the water area ( Figure 1). The quality of the fish catch decreased and the share of valuable fish species fell from 65% to 30% over 20 years. At the same time due to the building of the large reservoirs new industrial areas appeared. Fish species from other regions of the country started being acclimated to the native fish species. Thus, bream was released into the Irkutsk reservoir from the Ob reservoir in the Novosibirsk region. In some water bodies, the specialists from the Bolsherechensky fish farm began to breed the Amur carp. Mirror scaled carp and carp were released into Ordynskoye Lake, and juvenile omul, whitefish, carp and peled were released into the Bratsk reservoir.
New fish farms were built in the city of Bratsk, the village of Balagansk, and in the Usolye district they started a fish farm for stocking the Bratsk reservoir with valuable species of fish, such as sturgeon, Baikal omul, peled. All this made it possible to bring the industrial fish catch in reservoirs up to 40% of the total regional fish catch. In addition, due to the renewal of the fishing fleet and the introduction of new technologies, the gross output of the fishing industry increased (Yu.Yu. Argunova (2016) History of the fishing industry of Baikal Region in the 1900-1980-ies (PhD thesis in History), Irkutsk, Russia: Irkutsk State University).
However, since the 1960-ies. the role of the fishing industry in the region's economy steadily declined. The annual industrial fishing did not exceed 2.2 thousand tons. Due to the changed environmental conditions and anthropogenic impact, some species lost their former commercial value: the number of whitefish, sturgeon, taimen, sterlet, lenok and grayling decreased. In the total industrial fish catch, omul accounted for 40%, carp did for 25%, burbot, perch and pike did for 25%, the share of other species was 10%. The situation in the fishing industry before the collapse of the USSR is demonstrated in Table 3.    Figure 2). This is half of the fish catch of the end of the 19 th century. The recovery of the industry was no longer planned, but took place under market conditions of stiff competition from more efficient fishing areas in eastern and western Russia, as well as a supply of cheaper fish to the region, including that one from abroad. At the beginning of the 21 st century the volume of industrial fishing in the Irkutsk region did not exceed 300-500 tons per year (excluding recreational fishing). More than half of the total fish catch was from the water area of Lake Baikal, with the Angara reservoirs (the Bratsk and Ust-Ilimsk ones) ranking second. As for the rivers and small lakes industrial fishing does not exceed 70 tons here (Table 9), this area is mainly for recreational fishing.

Potential fish resources
This is the total biomass (ichthyomass) of all the fish species currently inhabiting all the water bodies of the Irkutsk region. They are estimated at 121 thousand tons. Their distribution among the water bodies of the region is demonstrated in Table 4. A high share of the Baikal water area in the gross fish stocks (59.5%) and in the absolute value of these stocks (72 thousand tons) is explained by the presence in the lake of a large number of fish that has no commercial value, primarily golomyanka, the total biomass of which is estimated at 37 thousand tons in the Irkutsk part of the Baikal water area, that is more than twice the biomass of all other Baikal fish species in the Irkutsk water area.

Commercial stocks of fish
These stocks are much smaller than the potential fish resources. This is due to the fact, that among almost 60 species of fish, inhabiting the water bodies of the region, not more than 10 species have commercial value, the biomass of these species is considerably less than the total biomass of all the species. Moreover, not all commercial fish can be withdrawn from the water bodies at the same time without affecting its reproduction.
Thus, the term commercial stocks describes the amount of possible withdrawal of only commercial fish species from the entire ichthyomass, with this withdrawal doing no harm to these species' further natural reproduction. It is considered that for low-value ordinary fish species the possible withdrawal should not exceed 40% of their annual growth in natural conditions, for valuable fish species it should not exceed 20-25%.
The total commercial fish stocks in the Irkutsk region are estimated at 10 thousand tons per year, which is considerably lower than its potential resources (Table 5). The distribution of commercial fish stocks among the water bodies of the region is also diverse (see Table 5). The major part of the stocks is in the reservoirs, the rivers, small lakes and ponds rank second. The share of the Irkutsk part of the Baikal water area accounts for 22% of the commercial fish stocks of the Irkutsk region, which is because of the decrease in the last decade in the number of omul, which is the main commercial fish of Lake Baikal.
Such a significant difference in the structure of distribution of gross fish resources among the water bodies is explained, first, by the exclusion of the non-commercial Baikal fish (holomyanka, bullhead, some gobies, etc.) from the total ichthyomass, and second, by the greater possibility of withdrawing low-value, but commercially important, ordinary fish from the water reservoirs and rivers. The littoral fish group is represented by grayling and whitefish, occupying mainly the coastal part of the lake to the depths of 5-7 meters (this group accounts for 38%).
As for the coastal-shallow bay fish group (represented by roach, perch, pike, dace, ide, etc.), inhabiting the system of interconnected shallow bays, deltaic areas and shallow waters, its share in the region does not exceed 18-23%. Such a small share is due to the absence within the Irkutsk region of high productivity coastal-shallow bay, deltaic and shallow water systems, which are characteristic of the western coast of Lake Baikal located in the administrative-territorial borders of the Republic of Buryatia. There is only one relatively shallow fishing area of Lake Baikal within the Irkutsk water area, i.e. the Maloe More Strait.

Distribution of fish stocks
Commercial fish stocks are distributed unequally throughout the Irkutsk region. The largest amounts of fish (more than 500 tons per year) are caught in the municipal areas adjacent to Lake Baikal, to the Bratsk and Ust'-Ilimsk reservoirs (Table 7). However, the development of fishing in reservoirs is hampered by their beds being badly clogged. Submerged timber makes it difficult to use nets and stake nets, makes it impossible to use more catchable seine nets, completely excludes larger water areas from fishing and thus drastically reduces the intensity of fishing in these fish-rich water bodies. The fish stocks of the Bratsk and Ust'-Ilimsk reservoirs are exploited more effectively in some specially prepared zones of their coastal areas, but the area of such zones does not exceed 10% of the water area of these reservoirs. In the small municipal districts of the region and also in the districts where there are no large water bodies and where fishing is not possible there is a prospect of aquaculture development. Among such territories can be considered the Shelekhov, Angarsk, Bayanday and some other districts. In some remote districts, for instance, the Mamsk-Chuysk and Bodaybo ones, it is possible to start industrial fishing by small fishermen teams, performed as a complementary activity with further selling the fish at the local market. In the districts where the fish stocks account for 40-400 tons per year, especially in the north of the Irkutsk region, the development of industrial fishing is hampered by technical and economic factors, i.e. low fish productivity of the water bodies, high cost of fishing, severe ice conditions, unpreparedness for fishing in the coastal area, lack of appropriate infrastructure, remoteness of target markets, low paying capacity of local consumers, etc.
The development of industrial fishing is also hampered by the fact that in a number of water bodies the fish stocks are mainly represented by ordinary fish species (such as perch and roach), which are not economically viable to catch. But even fishing for valuable fish species can be unprofitable if it is necessary to deliver fish to consumers at a distance of more than 250-300 km. In these areas, the development of fish stocks is possible through the development of recreational fishing and partly through ecological tourism.
Serious restrictions on industrial fishing were imposed by environmental pollution of the water bodies, for instance, the Bratsk reservoir, located in the area of large industrial enterprises.
The enumerated factors decrease economic effectiveness of industrial fishing, make it of low profit and even unprofitable despite the presence of significant fish resources and commercial stocks of valuable fish species.
In this regard, the water bodies for industrial fishing within the densely populated southern and central parts of the region can be rationally accessible and economically efficient. Here belong the river parts of the Angara river and adjacent to the railway parts of the Biryusa, Chuna, Iya, Oka, Belaya, Kitoy, Irkut, Lena and Kirenga rivers as well as some small lakes in this area. The main areas where fishing industry has developed are demonstrated in Figure 3. Thus, territorial, technical and economic and ecological limits change the current regional commercial fish stocks (11 tons per year), which decrease to the value of rationally available and economically efficient fish stocks, estimated at 4-5 thousand tons per year, including 1.3-1.8 thousand tons of valuable species.
As for the use of these fish stocks, the leading districts (with the fish catch of more than 100 tons per year) are those ones where fishing is well-organized. First of all, these are the Olkhon district, the Bratsk district and the Ust'-Uda district. The Balagansk municipal district was also among these, before closing down the Balagansk fish farm. The percentage of commercial fish stocks developed in the districts listed above ranges from 20 to 40%. In other areas the percentage does not exceed 10-20%.

Industrial fishing areas
Nowadays, the following areas are engaged in industrial and recreational fishing in the Irkutsk region: -the water area of Lake Baikal along the coast of the Irkutsk part of the Baikal region, mainly Maloye More (Alexander P. Sukhodolov, Sergey I. Violin, Oksana V. Teterina (2003). Development of Irkutsk Region's fish industry. Bulletin of Irkutsk State Academy of Economics, 2(35), 6-12.); -the Angara river basin (mainly in the Bratsk reservoir and the Ust'-Ilimsk reservoir); -the basins of the Lena river and the Nizhnyaya Tunguska river: -some other rivers and lakes of the Irkutsk region.
The average long-term share of the Bratsk and Ust-Ilimsk reservoirs in the total commercial fish catch is more than 45%, Lake Baikal (the Irkutsk part of the water area) accounts for 35-48%, the main rivers and their tributaries account for 7-9%. Nowadays, there is no industrial fishing in small lakes, there is recreational fishing here only.

Reservoirs
Within the Irkutsk region there are several reservoirs with the total area of 7.6 thousand sq km. Two of them, the Bratsk reservoir and the Ust'-Kut reservoir are of industrial fishing importance. The Irkutsk reservoir is not used for industrial fishing as it is very much pressed for fish stocks because of recreational fishing. Les us provide brief characteristics of these reservoirs.
The Bratsk reservoir. It is the most economically efficient industrial fishing reservoir. Its area is 5.5 thousand sq km, it contains 169 cubic km of water. Up to 40% of the Irkutsk region's commercial fish is caught here.
Due to the building of the reservoir here the hydrological, hydrochemical and biological characteristics of the Angara river significantly changed: the current disappeared, the depths increased, the composition of the ichthyofauna changed notably. Sturgeon, sterlet, taimen, lenok, whitefish, grayling, laying eggs in areas with strong currents and pebble soils, migrated to the tributaries and the upper part of the reservoir, where the river regime was preserved. As a result of the regulation of the Angara River, the range of these species was largely reduced and became fragmented, dramatically increasing the risks of extinction. Nowadays, these fish species are rarely found in the industrial fish catches. Without carrying out measures for their artificial reproduction, it will be impossible to preserve the population of these species.
Out of the ten fish species introduced to the Bratsk reservoir only three species have acclimated well, i.e. bream, carp, the Amur catfish. They have spread throughout the entire reservoir and are constantly present in industrial catches.
The commercial productivity of the reservoir can be increased by 2-3 times due to the pasture aquaculture of the whitefish species. However, this is hampered by the absence of an appropriate programme for the development of the region's industrial fishing complex, that requires appropriate state funding. For instance, there are only 70 ha of spawning areas, or 4.7% of the required 1,500 ha, on the Belsky fish farm (the village of Sosnovka in the Usolye district). The major part (82%) in the total industrial fish catch accounts for small ordinary fish, i.e. roach, perch, dace, crucian carp, the share of large ordinary fish, such as pike, carp, bream is 14%, while whitefish accounts for 4%.
In the early 1970-ies a fish farm was built at the coast of the Bratsk reservoir in the village of Balagansk. This fish farm provided the consumers of the Irkutsk region with frozen, smoked and dried fish, which was caught in the upper part of the reservoir (Yu.Yu. Angadaeva. Fisheries development of the Baikal region in 1945-1980-s. Socio-economic and humanitarian magazine Krasgau. 2018. № 3 (9). P. 150-161).
The industrial fishing in the Bratsk reservoir was steadily decreasing: in 2000, compared to 1990, it decreased by 5 times. The reason for the decrease was a ban on fishing, introduced by the Centre for the State Sanitary and Epidemiological Surveillance of the Irkutsk Region E3S Web of Conferences 389, 03028 (2023) https://doi.org/10.1051/e3sconf/202338903028 UESF-2023 due to the increased concentration (0.5-0.7 mg/kg) of technogenic mercury in the sediments of some parts of the reservoir (because of large chemical enterprises being located in its basin). The amount of fish with the mercury concentration exceeding MAC (in regard to fishing) in these parts of the reservoir increased. The distribution of mercury was very uneven. The deep bays were the least contaminated. The most contaminated areas were the area between the town of Svirsk and the village of Priboyniy, and, especially, the area of Maltinsk shallow waters. The contamination of the upper part of the Bratsk reservoir with mercury compounds resulted in closing the Balagansk fish farm. Now the ecological situation at the reservoir near the fish farm area has stabilised. Industrial fishing can be resumed, especially since recreational fishing has never stopped here. Prospects for this kind of industry are reappearing.
The Ust'-Ilimsk reservoir. It has the area of 1.9 thousand sq km and contains 59 cubic km of water. The reservoir is inhabited by 24 fish species. Roach, perch, bream, pike are of industrial and commercial value. Only 6% of the reservoir is developed for fishing and the reservoir's share in the total industrial fish catch of the region for now does not exceed 5%. Bratsk's wastewater, timber industry and submerged timber have a negative impact of the fish productivity of this district.
The Bratsk reservoir and the Ust'-Ilimsk reservoir developed as water bodies of the perchroach type, their feed supply, first of all, plankton is underused by the native fish species, thus, the necessity to acclimate the valuable fish species, namely, whitefish, omul, peled, is not in question. Breeding these species requires additional costs, both labour and material, as their habitat and breeding conditions are very specific (a special microclimate needs to be maintained in the water body).
The Irkutsk reservoir. Its area is 154 thousand km and it contains 2.1 cubic km of water. The total length of the reservoir is 56 km and its width ranges from 1 to 7 km. A complete water exchange occurs twice a month. The water in the reservoir meets the hydro-chemical characteristics of the Baikal water.
During the construction of the Irkutsk hydroelectric power plant, the reservoir was designed for grayling and lenok. Indeed, in the first years of its existence, this fish was abundant. At present, grayling is concentrated only in the upper part of the reservoir, and lenok can be found in exceptional cases. The taimen fish has probably disappeared. In the middle and lower parts of the reservoir, roach, bream, dace, perch and pike prevail. Occasional catches include crucian carp, burbot, the Amur catfish, carp and omul. In spring, grayling enters the bays and spawning rivers of the reservoir. In 1956-1962, 24 thousand individuals of bream, brought from the Ob Reservoir of the Novosibirsk Region, were released into the reservoir; they acclimated and now spawn in all the bays of the lower part of the reservoir. However, despite the fact that there are fish stocks, industrial fishing in the reservoir is currently not taking place due to the fact that its resources are being fully exploited by recreational fishermen.

Fishing areas of Baikal
Lake Baikal has traditionally been regarded as one of the country's major inland fishing water bodies. There are extensive fishing grounds here (Degtyarev V.A., Sherstyankin P.P., Melnik N.G. (2008). Distribution of omul (Coregonus Autumnalis Migratorius) in different regions of Lake Baikal according to acoustic data. Izvestia of the Pacific Research Fisheries Center. Iss. 152, 58-63.). Out of the 53 fish species inhabiting the lake and its tributaries, the following ones have commercial value: omul, grayling, whitefish, roach, dace, perch, crucian carp, pike, ide, burbot, as well as the three acclimated species, i.e. bream, the Amur catfish and carp.
Systematic fishing at Lake Baikal began in the 18th century, mainly in its coastal part with the relatively shallow areas, where the water is warmer and the fish feeds supply is of relatively high productivity and includes abundant zooplankton. The open deep-water part of the lake was hardly ever used by the fishermen.
There are several fishing areas at Lake Baikal. Two of them are located within the Irkutsk part of the lake.
The Malomorsky fishing area is one the oldest and largest fishing areas of Baikal, it occupies the whole water area of Maloye More and the and the western coastal part of the lake from the border of the region (in the north) to the source of the Angara river (in the southwest). Its current fish productivity is 8-9 kg per ha for commercial species. Before the early 1940-ies, however, the productivity of Maloye More was almost 15 kg per ha, i.e. twice as high. The average zooplankton biomass during the fish-growing period (in the mid-waters of up to 50 m of Maloye More) reaches 316 kg per ha, the benthos biomass is about the same, and the gammarids have a biomass of about 80 kg per ha.
The high fish productivity of the district enabled the building of the Malomorsky fish farm on Olkhon Island, in the village of Khuzhir, in 1938. In addition, the fish farm was designed to combine the small production facilities that were operating at that time in this part of Lake Baikal. Now Maloye More accounts for the catch of one quarter of the commercial omul stocks of Lake Baikal and the main amount of omul in the Irkutsk region. All the omul in Maloye More and adjacent areas of Lake Baikal, as well as in the south of Lake Baikal, is represented mainly by the Selenga population and the one of the north of Baikal (Alexander P. Sukhodolov, Andrei P. Fedotov, Mikhail M. Makarov, Alina V. Kolesnikova, Yakov A. Sukhodolov, Polina G. Sorokina (2021). Eco-legal and economic aspects of developing Malomorsky fishing area of Lake Baikal, Fisheries, 1, 2021). The population of the local tributaries has almost disappeared and measures need to be taken to artificially reproduce it. Other commercial fish caught include whitefish, grayling, roach, perch, pike and others. Fishing for omul in Maloye More is based on the withdrawal of two morpho-ecological groups: pelagic and coastal.
South Baikal fishing area. This area is located in the southwest end of the lake. Unlike in the Malomorsky fishing area there is no industrial fishing here as the concentration of the commercial fish stocks is low. It was only during the Second World War, in 1943, that the South Baikal fish farm was built here, which was mainly engaged in industrial fishing for yellowfin Baikal sculpin. After building the Irkutsk reservoir in the late 1950-ies and the water level rise in Lake Baikal by 1.4 meters, the coast of the lake was flooded and the fish reproduction conditions were disrupted. The fish stocks decreased and the fish farm began processing only imported oceanic raw fish. The fish farm capacity allowed for producing up to 30 thousand cans of canned fish per day. Many regions of the country were the sales market for this produce. In the 1990-ies the fish farm closed down. Further prospects of the area are associated with the development of sport and recreational fishing, whose annual catch estimates at 100-200 tons.

Lakes
Within the Irkutsk region there are 4 thousand small and medium-sized lakes, two hundred of them are suitable for recreational and sport fishing. The potential resources of fish are estimated at 1-2 thousand tons. However, at present time, they are not used for industrial fishing. This is due to their relatively low biological productivity. Eleven lakes, which are located near the recreation areas of the total area of 15 ha, and where there are mainly pike, perch and common minnow, are of sport and recreational fishing interest. The most attractive lakes for fishing can be Zaglin-Nur, Elgay, Bolshoye and Maloye Kurminskoe. Moreover, some lakes can be used for commercial fish farming in an industrial way.

Rivers
Within the Irkutsk region there are such large rivers as the Angara river (60 % of its total length), the Lena river (40% of its length) and the Nizhnyaya Tunguska river (18% of its length). Most of grayling, lenok, whitefish, taimen live and reproduce in these rivers and their tributaries. The total commercial fish stocks in all the rivers of the region are estimated at 2-3 thousand tons, including about 1 thousand tons in the Irkutsk part of the Lena river basin.
The share of valuable fish species in the river fishing areas is as follows: grayling is 14%, coarse chub is 27%, roach and perch are 59% of the total catch. Now it is mainly the Kirenga river and the Khanda river (in the Kazachink-Lensk district) that are used for industrial fishing. There is no industrial fishing in the other rivers as it is not cost-efficient, the fish productivity of these rivers is lower than that one of the lakes and reservoirs. However, almost all the rivers are used for recreational fishing, the share of which in the total fish catch is considerably higher than that one of industrial fishing. For instance, the amount of the grayling caught in the rivers of the region during recreational fishing can be ten times more compared to industrial fishing.
The rivers play an important role as a place for reproduction of some commercial fish species. Especially as the problem of artificial reproduction of valuable fish species and development of aquaculture (fish-farming) is relevant for the fishing industry of the Irkutsk region. Experts consider that in river fishing areas it is more efficient to develop fish reproduction facilities and recreational fishing; as for the increase of the share of industrial fishing this needs to be achieved on the basis of the pasture type reservoirs.
For more detailed evaluation of the rivers' fish stocks in the industrial fishing areas it is necessary to carry out further research. Especially as the ichthyological research carried out at the Angara river as well as the analysis of the current state of its fish resources potential and the development of measures for its restoration were suspended after the collapse of the USSR in the early 1990-ies and have not yet been resumed in full.

Commercial (pond) and industrial fish farming
This area for development is very promising as evidenced by the dynamics of the global development of the industrial ways of fishing and getting fish-based products. Year-round industrial commercial fish farming is also possible in the Irkutsk region, where it is advisable to create an experimental production complex and a network of small commercial fish farms. On the Angara river within the city limits of Irkutsk in special cages they have begun to farm commercial trout. Developing aquaculture in specially equipped ponds on an industrial scale is being considered. In the long term, the existing infrastructure needs to be modernized, aquaculture facilities need to be built and the processes of catching and processing fish need to be organized more efficiently.

Conclusion
The Irkutsk region has enormous reserves of water bodies with natural industrial fish stocks. This creates favourable terms for the development of fishing as well as the basis for obtaining high quality fish products from the native and acclimated fish species.
The development of fishing as an industry in the region was occurring near the most productive water bodies and was aimed at satisfying the demands of the local market. Uneven distribution of the fish stocks and uneven development of the territory have also had an impact on the fishing industry development and have formed its spatial structure. Fishing prospects in the region are connected with the preservation of the fish productive water areas and the necessity to reproduce the fish stocks. The industry will still be aimed at satisfying the demands of the regional food market with regard to the development of tourism and the increase of the number of tourists in the Baikal region. This will enable to develop recreational and sport fishing more actively. Industrial fishing will be more and more replaced with the aquaculture industry. Even now on the Angara river within the city limits of Irkutsk in special cages commercial trout is farmed. Projects of developing aquaculture in specially equipped ponds on an industrial scale are being considered.