The article is devoted to the analysis of data on Baikalian omul Сoregonus migratorius (Georgi, 1775) obtained using the hydroacoustic method of accounting. Material was collected in the Chivyrkuisky and Barguzinsky bays of Lake Baikal in 2000–2008. The accounting was carried out in June – July from the vessel “PTS-150” project, from which control trawlings of detected accumulations of fish were carried out. Trawling was carried out at a vessel speed of 4.5 km / h, to a depth of 50 m. To obtain control catches from maximum depths, gill nets of standard size were used. To collect sonar data, the ASKOR hardware-software complex was used. The complex automatically calculates the number of fish in the water layer up to 300 m and determines the size range of targets, starting with a commercial fish length of 2 cm. Omul in the Barguzinsky Bay hibernates at depths of 200–400 m, but already in April it is found at a depth of 150–100 m, and in May it reaches shallow waters. In the Barguzin Bay in June the omul biomass was very small (1-2 kg/ha), apart from the summer data of 2001, when the total stock of omul was more than 500 tons (97 kg/ha). In summer, a significant part of omul (33 % in abundance and 36 % in biomass) remains at a depth of 100-250 m, where dense clusters of large-sized fish are formed, probably near-bottom groups. In Chivyrkuisky Bay, there is a population of omul belonging to the bottom-deep-water morpho-ecological group. This omul spawns in the rivers flowing into the Chivyrkuisky Bay, and its range is limited to this bay, and Sosnovka Bay, which is part of the Barguzinsky Bay. According to sonar survey data, the bulk of omul was concentrated in the central part and in the depths of the Chivyrkuisky Bay – in the water area between Cape Kurbuliksky and Bezymyanny. Omul concentration reached here of 1000–2000 ind/ha. Two small-sized spots of omul concentration were noted in the immediate vicinity of the Bol’shoy Chivyrkuy River – spawning river of the Chivyrkuy omul population. It cannot be ruled out that it was the omul that created the clusters. The total omul biomass in the bay is estimated at 254 tons (20.9 kg/ha).

Varnavskii Andrei Valentinovich, Senior Specialist, Baikalian Branch of VNIRO FSBSI, 4b, Khakhalov st., Ulan-Ude, 670034, Russian Federation, e-mail: daos@rambler.ru

Varnavskii A.V. Distribution of Baikalian Omul Сoregonus migratorius (Georgi, 1775) in the Water Area of the Barguzinsky Fishing Region of Lake Baikal according to Sonar Data. The Bulletin of Irkutsk State University. Series Biology. Ecology, 2019, vol. 29, pp. 40-59. https://doi.org/10.26516/2073-3372.2019.29.40 (in Russian)

Gidroakusticheskii uchet resursov baikal'skogo omulya [Hydroacoustic accounting of the resources of the Baikal omul]. Novosibirsk, Science Publ., 2009, 244 p.

Degtev A.I., Ivanter D.E. Avtomatizirovannaya sistema kolichestvennoi otsenki rybnykh zapasov gidroakusticheskim metodom ASKOR-2 ]Automated system for the quantitative assessment of fish stocks by the hydroacoustic method ASKOR-2]. Rybnoe khozyaistvo [Fisheries], 2002, no. 4, pp. 32-40.

Degtev A.I. Vnedrenie gidroakusticheskogo programmno-tekhnicheskogo kompleksa “ASKOR” v praktiku kolichestvennoi otsenki zapasov omulya ozera Baikal [Implementation of the ASKOR sonar software and hardware complex into the practice of quantitative assessment of omul stocks of Lake Baikal: Report]. Baikal Br. Gosrybtsentr. Petrozavodsk, 2008, 29 p.

Kozhov M.M., Spelit K.K. Barguzinskii promyslovyi raion [Barguzinsky fishing area]. Ryby i rybnoe khozyaistvo v basseine ozera Baikal [Fish and fisheries in the basin of Lake Baikal]. Irkutsk, Irkutsk St. Publ., 1958, pp. 605-637.

Materialy, obosnovyvayushchie ob"emy obshchikh dopustimykh ulovov vodnykh bioresursov v ozere Baikal s vpadayushchimi v nego rekami na 2011 god (s otsenkoi vozdeistviya na okruzhayushchuyu sredu) [Materials to justification of the total allowable catches of aquatic biological resources in Lake Baikal with rivers flowing into it for 2011 (with an assessment of the environmental impact)]. Baikal Br. Gosrybtsentr. Moscow, VNIRO, 2010, 74 p.

Misharin K.I. Baikal'skii omul' [Baikal omul]. Ryby i rybnoe khozyaistvo v basseine ozera Baikal [Fish and fisheries in the basin of Lake Baikal]. Irkutsk, Irkutsk St. Publ., 1958, pp. 130-287.

Otsenit' sostoyanie zapasov vodnykh biologicheskikh resursov, razrabotat' rekomendatsii po ikh ratsional'nomu ispol'zovaniyu, prognozy ODU i vozmozhnogo vylova na 2014 g. v presnovodnykh vodnykh ob"ektakh zony otvetstvennosti FGUP «Gosrybtsentr» [Assess the state of stocks of aquatic biological resources, develop recommendations for their rational use, forecasts of ODEs and possible catch for 2014 in freshwater bodies of the FSUE Gosrybtsentr responsibility zone]. Gosrybtsentr. Ulan-Ude, 2013, 38 p. 

Peterfeld V.A. Rybokhozyaistvennoe ispol'zovanie vodnykh biologicheskikh resursov (ryb) na osobo okhranyaemykh prirodnykh territoriyakh (na primere Chivyrkuiskogo zaliva ozera Baikal) [Fisheries use of aquatic biological resources (fish) in specially protected natural areas (on the example of the Chivyrkuisky Bay of Lake Baikal): Candidate in Biology dissertation abstract]. Novosibirsk, Novosibirsk St. Agr. Univ., 2015, 22 p.

Pravdin I.F. Rukovodstvo po izucheniyu ryb (preimushchestvenno presnovodnykh) [Guidelines for the study of fishes (mainly freshwater)]. Moscow, Pishchepromizdat Publ., 1966, 376 p.

Redkozubov Yu.N. Cheshuya baikalskogo omulya – kak pokazatel' nekotorykh momentov ego biologii [Scales of Baikal omul as an indicator of some aspects of its biology]. J. Ichthyol., 1968, vol. 8, is. 5 (52), pp. 919-930.

Semovskii S.V., Shimaraev M.N., Min'ko N.P., Gnatovskii R.Yu. Ispolzovanie sputnikovykh nablyudenii dlya issledovaniya termicheskikh frontov ozera Baikal [Use of satellite observations to study the thermal fronts of Lake Baikal]. Issledovanie Zemli iz kosmosa [Earth exploration from space], 1998, no. 5, pp. 65-75.

Smirnov V.V., Smirnova-Zalumi N.S., Sukhanova L.V. Mikroevolyutsiya baikal'skogo omulya [Microevolution of Baikal omul]. Novosibirsk, SB RAS Publ., 2009, 193 p. 

Smirnov V.V., Smirnova-Zalumi N.S., Orlov S.I. Sovremennye tendentsii v raspredelenii i promyslovykh ulovakh baikal'skogo omulya Coregonus autumnalis migratorius (Georgi) [Current trends in the distribution and commercial catches of Baikal omul Coregonus autumnalis migratorius (Georgi)]. The Bull. Irkutsk St. Univ. Ser. Biol. Ekol., 2013, vol. 6, no. 3(1), pp. 63-67. 

Shimaraev M.N., Grachev M.A., Imboden D.M., Okuda S., Granin N.G., Kipfer R., Levin L.A., Endo Sh. Mezhdunarodnyi gidrofizicheskii eksperiment na Baikale: protsessy obnovleniya glubinnykh vod v vesennii period [International hydrophysical experiment on Baikal: processes of updating deep water in the spring]. Doklady AS, 1995, vol. 343, no. 6, pp. 824-827.