Sima: detailed description, lifestyle, habitat and reproduction

The masu salmon: a detailed description, lifestyle, habitat, and reproduction. The masu salmon (Oncorhynchus masou) is one of the most beautiful and powerful Pacific salmon, prized for its exceptional meat flavor, high fat content, and fighting ability when reeled in. It is an anadromous fish, spending most of its life at sea and entering the rivers of the Far East and North America to spawn. The masu salmon is also known as masu, Japanese salmon, cherry salmon, or masu char. Its flesh is bright red, very fatty (up to 15–20%), tender, and flavorful, and its caviar is among the largest and most delicious of all Pacific salmon. The masu salmon is a key target for sport and recreational fishing in Kamchatka, Sakhalin, the Kuril Islands, and Primorye.

When a Sim is caught

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Sima can be caught all year round, but the bite is very seasonal:

• January–March — ice fishing in non-freezing sections of rivers and lakes (bite is weak, but possible)
• April–May — spring feeding frenzy after ice drift, especially active in the lower reaches of rivers
• June–July is the summer peak of activity in rivers and lakes
• August–September – pre-spawning run, the most powerful bite
• October–November is the spawning period, the bite remains, but the fish become capricious
• December is the winter low, fishing is only possible in deep holes

The most stable and strong bite is in August–October, when the masu actively feed before spawning and during the run to the rivers.

Spawning of masu salmon

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Cherry salmon spawn from September to November (in some northern populations, until December to January). This is one of the latest spawning seasons among Pacific salmon. Water temperatures during spawning are typically 1–6°C, often under ice.

The female chooses clean areas with a pebble or gravel bottom and a moderate to strong current. The depth is 0.5–2 m. She digs a nest with her tail, 15–40 cm deep. The eggs are large (5–6 mm), orange-yellow, and heavy. During the season, the female makes 3–8 visits and lays 2,000 to 8,000 eggs.

Males actively guard the nests. After spawning, the masu dies—a biologically programmed death. Egg development lasts 5–7 months. The fry emerge in the spring (April–June), initially feeding on the yolk sac, then switching to zooplankton and insect larvae. The juveniles remain in the river for 1–3 years (usually 2 years), after which they migrate to the sea.

Description of the Sim

At sea, the masu salmon has a bright silvery coloration with a strong metallic sheen. The back is dark blue or green, and the belly is white. On the sides are numerous large light spots with pink, crimson, orange, or reddish hues (sometimes called "pearls"). The fins are pinkish-red.

After entering the river, the coloration changes dramatically: the body darkens, the back becomes green-brown, and the spots become bright pink, crimson, or red. The spots above the lateral line are numerous and small, while those below are larger and sparser. During spawning, the coloration becomes even more contrasting: males become covered in bright red and orange spots, their bellies and fins turn crimson, and a protrusion appears on their lower jaw.

The juveniles (the "speckled") have transverse dark spots on the sides, separated by light spaces.

The masu salmon in its classic form does not inhabit the Putorana Plateau, but a closely related species, the Arctic char (Salvelinus alpinus), does. It has similar coloration, behavior, and trophy qualities. The plateau's conditions (icy clear water, high oxygen levels, pebble bottom, and strong currents) are virtually identical to those in the Far East rivers where masu salmon reach their maximum size and display their best qualities.

Habitat and behavioral characteristics

The range of the masu salmon covers the northern part of the Pacific Ocean:

• along the Asian coast - from the Bering Strait to North Korea and Japan
• in American - from Alaska to California

The masu salmon is primarily an anadromous fish, but it also forms resident freshwater populations. Juveniles live in rivers for 1–3 years, then migrate to the sea. Marine migrations can extend over hundreds of kilometers.

Freshwater forms:

• lake-river - fattens in lakes, spawns in streams and tributaries
• lake - lives and spawns only in the lake

While masu salmon are absent from the Putorana Plateau, it is home to Arctic char, which lead a very similar lifestyle: cold, icy water, high oxygen levels, a pebble bottom, strong currents, and an abundance of natural food. The plateau's hydrological, temperature, and trophic conditions are very similar to those of the Far Eastern rivers where masu salmon reach their largest sizes and display their best qualities.

Sima's nutrition

The masu is a predator and benthophage. Juveniles feed on:

• larvae of aquatic insects (mosquitoes, caddis flies, mayflies)
• crustaceans (amphipods, mysids, shrimp)
• mollusks
• insects falling into the water

An adult Sim actively eats:

• small fish (young whitefish, grayling, smelt)
• salmon caviar (especially chum salmon and pink salmon)
• crustaceans
• mollusks
• insect larvae

During salmon spawning, masu trout gather under riffles and in pits below spawning grounds, where they feed en masse on the eggs that roll down and are squeezed out of the females' abdomens. This is one of the masu trout's main food sources in spawning rivers.

On the Putorana Plateau, closely related salmonid species (Arctic char and lenok) share a similar diet: insect larvae, crustaceans, small fish, and the eggs of other species. The abundance of natural food in the pristine rivers and lakes allows these fish to reach large sizes and high-fat meat.

Reproduction of Sima

Cherry salmon reach sexual maturity at 3–5 years of age. Spawning occurs in September–November (sometimes until December–January) in mountain lakes, springs, and fast-flowing mountain rivers.

During the spawning period, the migratory masu acquires its breeding plumage:

• the body darkens
• the spots become brighter
• the belly and fins acquire a red or orange color
• In males, a growth appears on the lower jaw

The female buries her eggs in the soil. After spawning, the masu dies—this is a biologically programmed death.

Spawning fish exhibit almost absolute homing—almost 100% of individuals return to their natal river.

On the Putorana Plateau, closely related salmonid species (Arctic char and lenok) reproduce in similar conditions: mountain lakes, springs, and fast-flowing rivers. Here, the fish reach sexual maturity at 4–6 years of age, spawn in the fall, from September to November, and many individuals survive the spawning season, returning to the lakes to feed.

Methods for catching sima

The masu salmon bites actively only in rivers and lakes. It's rarely caught in the sea. In open water, it's caught with a float rod, spinning rod, and bottom fishing rod.

The following is used as a nozzle:

• lard
• salted sockeye salmon meat
• deer and bear meat
• cranberry
• caddisfly
• maggots
• sometimes artificial baits - flies and spoons

Pork fat, venison, bear meat, and fish are cut into small, elongated slices 3–4 cm thick. A combination of pork fat on the shank and venison or bear meat on the hook point produces good results.

Sometimes salmon are caught better with pork fat alone or in combination with a piece of red foam rubber. Lingonberries are a good bait when fishing with a running bottom rod in September on fast-flowing mountain rivers.

In summer, catching masu salmon using caddis flies and maggots gives particularly good results.

Salmon will bite on spoons and artificial flies in the summer, and on vertical spoons in the winter, but significantly less than on all other lures. Moreover, they prefer brown and black flies.

Experienced anglers always have a fishing rod, spinning rod, bottom fishing rod, and even a fly boat on hand. This allows them to fish every hole in the river or lake using all available methods and offer salmon a wide variety of baits.

The masu trout bite in autumn is very different from the summer one. Congregating in the holes, they lose their caution and sometimes bite greedily, quickly dragging the tackle to the bottom and away. After such bites, the masu trout hook themselves. But this doesn't happen very often, so hooking is essential, and afterward, care is taken to prevent the prey from escaping under the ice where the angler is standing, otherwise they will snag or break the tackle. Incidentally, very large masu trout bite at this time.

In winter, masu salmon are caught in rivers using fresh fish (sockeye salmon). A sinker is lowered into a hole to the bottom, lifted slightly, and periodically twitched upward. A bite occurs when the bait rises. When the bite is poor, they don't stay in one place for long, but move around the river in search of fish holding areas. Small masu salmon typically stay in small schools in the current at this time, while larger ones hang out under steep banks, snags, at the edge of the current and still water, or in backwaters.

In lakes, salmon are hunted with a medium-sized spoon (4–6 cm), white or yellow, with a tightly soldered double or single hook.

Spring fishing begins in the rivers adjacent to the Okhotsk coast in mid-May, when they open up, and later in the northern part of the Magadan region.

Awakening from hibernation, the river quickly carries ice floes down its center. But in quiet spots near the banks, the ice lingers. Medium and large fish, still afraid to venture into open water, hide beneath it. Knowing the deep holes, you can successfully catch salmon from the remaining ice floes in the winter.

At the end of May and June, when migratory fish mostly go to sea, the bite of masu salami weakens somewhat.

Arctic char are caught by jigging in shallows where the fish congregate in large numbers. The bait is cast 15–20 meters above the fishing spot and held at eye level. It's best to use a lightweight spinning rod, which is easy to cast, as well as the hooked fish. When jigging or spooning for masu salmon, avoid making sudden movements to avoid disturbing the school.

While masu salmon fishing is not possible on the Putorana Plateau, fishing for closely related salmon species—Arctic char, lenok, and whitefish—is popular here, using spinning and fly fishing in the pristine rivers and lakes. The plateau's conditions are ideal for large specimens, but access is extremely difficult.

Nutritional value of masu

Cherry salmon meat is a source of high-quality protein (18–22 g/100 g), healthy omega-3 fats, vitamins D, B12, A, E, phosphorus, potassium, selenium, and iodine. Caloric value: 150–200 kcal/100 g.

Salmon is beneficial for the heart, blood vessels, brain, immune system, skin, hair, and vision. It is recommended for anemia, high cholesterol, depression, and recovery from illness.

On the Putorana Plateau, salmon meat is extremely pure and rich in nutrients thanks to its natural diet and the absence of pollution.

The masu salmon is a striking example of Pacific salmon. Unlike the freshwater giants of the Putorana Plateau—taimen, lenok, and char—which reach remarkable sizes in crystal-clear rivers and lakes thanks to the pristine environment and abundant natural food, the masu salmon combines marine feeding and freshwater spawning. It rules the coastal waters and rivers of the Far East, where its silvery schools and vibrant spawning remain an unrivaled spectacle of the wild.