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Sima, or Masu (Oncorhynchus masou)

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The body is high. Scales are quite large. Along the lateral line are 128-145 scales. In the back fin 10-13 rays, in the anal 11-15. Coloring: the back is gray-blue, the sides are silvery with many dark small spots on the back, tail, dorsal and fat fins. Below the sideline are gray-blue spots and stripes. Grows up to 70 cm.

Found on the Asian coast of the Pacific Ocean, Japan, Korea, Taiwan. It has two subspecies - O.m. formosanus (endemic to Taiwan) and O.m.macrostomus (Japan).

It has a passing (majority) and freshwater form. It feeds on insect larvae and fish. The pass-through form spawns in May-June and may spawn at the end of July. Caviar is buried in the ground. Fertility is up to 5,4 thousand eggs. The young come out of the ground in March-April and slide into the sea in the second year of life, but a certain number of males can remain in the river and live in it all their lives, spawning along with migratory forms. After spawning, adult fish die. Only dwarf males that live in the river remain alive.

SIMULAR BIOLOGY

Sima migratory fish: lives in the sea, breeds in rivers. In Japan forms a residential form in rivers and lakes. Spawns once in a lifetime, after which it dies.

It takes place in Amur from late July to mid-August, in Posyetsky district - in September, in Japan - in September - October. Spawning occurs at a temperature of 7-12 °, on the small pebble soil in which the eggs are buried.
Fertility is 1.4-5.2 thousand eggs, an average of 3.2 thousand eggs.

Caviar, like all salmon, is bottom. Juveniles linger in the river for up to a year, reaching a length of more than 10 cm, sometimes 18-20 cm. Juveniles of this size have 7-11 large black transverse stripes on the sides of the body.

Sima reaches a length of 71 cm and a weight of 9 kg.
The sizes of Sim fishing fish are different in different areas. In Posyetsky district, the length is 52-68 cm, on average 61 cm, weight 4 kg, in the river. Cumin flowing into the Tatar Strait, length up to 71 cm and weight up to 9 kg (medium: length 60-63 cm, weight 4-5.5 kg), in the lower reaches of the Amur River 46-67 cm, average 54-57 cm, weight -1.6-3.2 kg, an average of 2.3 kg.
Residential freshwater form of Sim fish reaches a length of only 28 cm. Sim usually ripens in the third, less often in the fourth year of life. Male Sims lingering in the river reach puberty already at a length of 18 cm.

Sima is a predator, like other Pacific salmon.

Other species of the genus Oncorhynchus are pink salmon and others.

Sima is the first migratory salmon to enter Amur after opening it, in some years from the beginning of May, usually from mid-May to early June. Like pink salmon, and unlike chum salmon, it goes to Amur from the south, from the Sea of ​​Japan. The height of the course in the lower reaches of the Amur River in mid-July, the end - in late July - early August.
In the Amur, single specimens rise 300-400 km above Nikolaevsk. Juveniles roll into the sea at the age of about a year or more.

FISHING SIMA

Sima is mined only within Russia, Korea and Japan. Japanese catches reached 292 thousand centners in 1915 (in 1923-1925 they did not exceed 126 thousand centners, and in 1936-1938 they fell to 100 thousand centners), with the largest quantities being harvested from Hokkaido. In Korea, catches amounted to 8-26 thousand tons (1936-1939).
In the waters of Russia, the sim is few in number, and its catch was 6–9 thousand tons (1936–1939), the largest catches were in the river. Tumnin, further in pp. Mine, Botchi, Samarga. Sima is the subject of artificial breeding.

Technique and course of fishing

The sim is caught during the course of the fixed and casting net (in Japan also by gill nets).

Three quarters of the total catch is treated with medium or strong salting, sometimes followed by cold smoking. Part of the catch goes ice-cream to the market.
To a small extent used for the preparation of balyk products. Caviar is salted.

Sims dimensions and weight

The length of the upper jaw in males is 14.9-17.1, in females 12.6-13.2% of the body length (to the end of the middle rays C). The diameter of the eye decreases significantly with age: in young people (up to 200 mm) it is 20-30% of the length of the head, and in adults it drops to almost 10%. In juveniles, there are 6–11 dark transverse spots on the sides of the body, there are no spots on the dorsal and caudal fins, and 1–4 black spots around the pupil.

The length (to the end of the middle rays C) of adult males from the river. Tumnin (flows into the Tatar Strait) on average 63 cm (maximum 71 cm), average weight 5.5 kg (maximum 9.0 kg), females average 60.5 cm (maximum 67 cm), average weight 4, 0 kg (maximum 6.0 kg). In Posyetsky district (near the border: with Korea) a large sim is also caught: females are 52-68 cm. In the lower reaches of the Amur, the sizes are smaller: males 46-67 cm, on average 56.8 cm, weight 1.8-3.2 kg, on average 2.3 kg, females 47-62 cm, an average of 54.4 cm, weight 1.6-3.1 kg, an average of 2.3 kg.

Spread

Passing and freshwater forms of the Pacific basin, living only on the Asian coast from the peninsula of Korea and Japan (Hokkaido and Honshu) to the Amur, Sakhalin and the western coast of Kamchatka. Residential form is presented in lakes and rivers, including Taiwan and the Ryukyu Islands, on the Peninsula of Korea and in Japan.

Lifestyle

After the opening of the Amur Sim, the first of the passage salmon enters the river - in other years in early May, usually from mid-May to early June. Like pink salmon, and unlike chum salmon, it enters Amur from the southern fairway, i.e., from the Sea of ​​Japan. How high it rises, is unknown. Has freshwater dwarf forms. The move begins early in May, and continues until early September. It does not rise high in the rivers, but it goes higher than pink salmon.

Puberty

Sima is a relatively precocious species: it reaches puberty usually in the 3rd, less commonly in the 4th year. Dwarf males mature at a length of 10-22 cm, weighing about 88 g at the age of 1-2 years. In Japan, and female sims reach puberty, remaining in fresh water.

Propagation of Masu

It enters the rivers earlier than other salmon (in May-July). Spawning in late July-September (in the south until October). The height of the course in the lower reaches: Amur falls in mid-July, the end - in the second half of July, early August. Spawning in the lower reaches of the Amur since the end of July. The number of eggs on average 3200 pieces. In Posyetsky district, the course is later than in Amur, precisely around mid-August and at the end of this month, spawning in mid-late September. Spawning grounds are located in the upper reaches of the rivers. Caviar is laid in nests on pebble-silty soils. The average fecundity of 3.2 thousand eggs. After spawning, fish die, dwarf ones can partially survive and slide into the sea.

Caviar develops in the ground. The incubation period is 50-70 days. After 25-30 days, dark transverse spots appear on the sides of the fry, teeth appear. Young come out of the ground in March-April. By the end of July, juveniles reach a size of 40 mm. Young Sims remain for a long time in the river, about a year, reaching a length of over 100 mm, sometimes 180-200 mm. In juveniles of this size, on the sides of the body there are 7-11 large black transverse stripes, 3 large spots at the upper ends of the transverse stripes, small rounded spots on the back above the transverse stripes, sometimes there are rounded spots and below the transverse stripes, at the base of the dorsal fin there are 3 dark spots, the fins are colorless, sometimes a black spot at the base of the fatty fins. The body is high, anal fin with tenderloin, decreasing with age. Young fish 50-60 mm long are shifted to reaches and rifts of the pivotal part of the river. In the second year of life, part of the juveniles slides into the sea. Stingray in the sea begins in the spring.

Economic value

In Russia, the sim is small. In the Amur, it is not caught much, and here it is recorded in catches as pink salmon. Catch during the course of the fixed and casting net. Three quarters of the catch is processed by the ambassador, part of the catch is delivered to the market in ice cream. Caviar is salted.

Literature:
1. Lebedev V.D., Spanovskaya V.D., Savvaitova K.A., Sokolov L.I., Tsepkin E.A. USSR fish. Moscow, Thought, 1969
2. L. S. Berg. Freshwater fish of the USSR and neighboring countries. Part 1. Edition 4. Moscow, 1948
3. Atlas of freshwater fish in Russia: In 2 volumes. T.1. / Ed. Yu.S. Reshetnikova. -M .: Nauka, 2003 .-- 379 p.: Ill.

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