Omul

The omul, Coregonus migratorius, also known as Baikal omul ( ), is a whitefish species of the salmon family endemic to Lake Baikal in Siberia, Russia. It is considered a delicacy and is the object of one of the largest commercial fisheries on Lake Baikal. The omul originated from Arctic whitefish that entered Lake Baikal via river systems roughly 20,000 years ago during the last glaciation. Adaptation to local conditions led to several ecological and morphological forms. Three main groups are recognized: the Pelagic omul, coastal omul, and benthic deepwater omul. The pelagic omul inhabits open water, spawns mainly in the Selenga River, and undertakes the longest migrations. The Coastal-pelagic Omul are common in North Baikal, feeding in nearshore waters and ascending to surface layers at night. The Benthic-deepwater Omul are associated with small-river populations and found in deeper slope habitats.

The omul, Coregonus migratorius, also known as Baikal omul ( ), is a whitefish species of the salmon family endemic to Lake Baikal in Siberia, Russia. It is considered a delicacy and is the object of one of the largest commercial fisheries on Lake Baikal. The omul originated from Arctic whitefish that entered Lake Baikal via river systems roughly 20,000 years ago during the last glaciation. Adaptation to local conditions led to several ecological and morphological forms. Three main groups are recognized: the Pelagic omul, coastal omul, and benthic deepwater omul. The pelagic omul inhabits open water, spawns mainly in the Selenga River, and undertakes the longest migrations. The Coastal-pelagic Omul are common in North Baikal, feeding in nearshore waters and ascending to surface layers at night. The Benthic-deepwater Omul are associated with small-river populations and found in deeper slope habitats. ==Taxonomy== The omul has traditionally been regarded as a subspecies of the Arctic cisco Coregonus autumnalis. However, recent genetic studies have shown it actually belongs to the circumpolar Coregonus lavaretus-clupeaformis complex of lake whitefishes, which also has other members in Lake Baikal, and it is now considered its own species within Coregonus. The four or five traditionally accepted subpopulations of omul within Lake Baikal are: North Baikal (северобайкальский), Selenga (селенгинский), Chivyrkui (чивыркуйский) and Posolsk (посольский). These vary in size, feeding behaviors and preferred spawning habitats. The extent of their reproductive isolation is debated. ==Description== The omul is a slender, pelagic fish with light silver sides and a darker back. It has small spots on its dorsal fin and larger ones on its head, a terminal mouth position and a large number of gill rakers, typical of fish that feed in the pelagic zone. The mean size of adults is 36–38 cm and 0.6 to 0.8 kg, though the maximum reported length is 56 cm weighing about 2.5 kg. The subpopulations on the northern end of the lake tend to be smaller. ==Behavior== The omul feeds primarily on zooplankton, smaller fish, and occasionally some benthic organisms. It feeds primarily in the rich pelagic zone of Lake Baikal up to 345–450 m. It is a relatively long-lived, iteroparous species that attains reproductive maturity at five to 15 years of age. The omul only enters the rivers that feed Lake Baikal to spawn, like the Selenga, initiating short spawning migrations, usually in mid-October, broadcasting 8000–30000 eggs before returning to the lake. Based on Hydroacoustic observations, Omul exhibits three distinct behavioral strategies during the winter that reflect feeding activity and energy conservation. The energy conservation strategy observed in Omul involves resting at depths greater than 200 meters, where the fish remain largely inactive. The feeding activity strategies involve Vertical migrations and schooling behavior with horizontal migrations and active foraging for aggregated food sources. ==Diet== The omul's main food source is an endemic species of alga, Melosira. The increase in absolute individual fecundity (AIF), the total number of eggs produced by a single female fish during one spawning season, was considered to have an adaptive value, contributing to the recovery of the Baikal Omul population. In 2019, the average AIF was reported at 18,572 eggs, increasing to 19903 ± 549 in 2020. Statistical analysis confirmed a significant relationship between age and fecundity (F = 4.16 > Fcritical = 2.56, P = 0.006). Older individuals 11-12+ years produced approximately 4,475 more eggs than younger fish 9+ years, indicating that fecundity rises with age. However, relative individual fecundity (eggs per gram of body weight) decreased with age, from 33.83 units/g (8+) to 27.81 units/g (12+). A comparison of 2019 and 2020 data also showed slightly higher relative fecundity in 2020 most age classes, suggesting improved reproductive conditions following the fishing ban. ==Consumption and fishery== Omul is one of the primary food resources for people living in the Baikal region. It is considered a delicacy throughout Russia, and export to the west is of some economic importance. Smoked omul is widely sold around the lake and is one of the highlights for many travelers on the Trans-Siberian Railway, and locals tend to prefer the fish salted. A popular Siberian salad called stroganina consists of uncooked frozen omul shaved thinly and served with pepper, salt and onion. Omul is also used in a dish called saguaday which is a salad made of raw omul with salt, pepper, and oil. Another common preparation involves freshly caught omul: the fish is carefully washed, salted, and pierced along its ridge with a wooden stick. The piercing must be gentle, in order not to damage the gallbladder. The skewered omul is then roasted and served with scallions or rice. Due to its high demand, the omul is the object of one of the most important commercial fisheries in Lake Baikal. The highest recorded annual landed catches occurred in 1940s and amounted to 60-80 thousand tonnes. A subsequent crash in the population led to a closing of the fishery in 1969, followed by a reopening with strict quotas in 1974 after some recovery of the stocks. Currently, the omul fishery accounts for roughly two-thirds of the total Lake Baikal fishery. Fluctuations in the population and intensive fishing make sustaining the fishery one of the highest priorities for local fisheries managers. In 2017, the Ministry of Agriculture of the Russian Federation banned commercial amateur, and sport fishing of Baikal omul to prevent further stock depletion. In an effort to address overfishing while exploring sustainable commercial practices, a study was conducted that investigated the mathematical modeling of Baikal omul populations. The model describes how the population changes depending on whether natural growth or fishing pressure is greater. The researchers used this framework to identify conditions that would allow sustainable fishing while avoiding population collapse, and to evaluate potential long-term management strategies for conserving omul in Lake Baikal. Freshly caught Baikal omul.jpg|Freshly caught Baikal omul Baikal omul.jpg|Baikal omul Baikal smoked omul on the counter of the store.jpg|Baikal cold-smoked omul on the counter of the store Omul on a cutting board.jpg|Omul on a cutting board ==See also== Stroganina ==References== ==External links==

Text derived from https://en.wikipedia.org/w/index.php?oldid=1373736001 under CC BY-SA 4.0; modifications have been made.