Chinook salmon

The Latin name for Chinook salmon is Oncorhynchus tshawytscha.

The Chinook salmon is one of the most productive Pacific salmon. The decrease in fish populations is probably due in large part to habitat deterioration from the erosion that has occurred as a result of timber harvesting, and to a lesser extent due to the introduction of exotic species that have disrupted the salmon’s growth. The Chinook salmon is an andromedin fish species. That means that it is born in freshwater, migrates to saltwater or brackish water when it grows larger, and then migrates back to its birthplace to reproduce. The Chinook salmon is the largest of the Pacific salmon. They are found throughout the northern Pacific Ocean from latitudes 35 ° N to about 70 ° N. Domestic areas include Alaska, Canada, the northwestern United States, Russia, and Japan.

The Chinook salmon has been planted all over the world but has only managed to establish itself fully in certain places in the world. This means that they can spawn and reproduce there naturally. Places they have managed to establish themselves in are: New Zealand, Chile, Argentina and the great lakes along the border between the USA and Canada. All other attempts at introduction have failed.

The Chinook salmon is not considered an invasive species.

The Chinook salmon have been deliberately placed in lakes to keep down the population of alewives.

It is not yet known whether the spread of the Chinook salmon in southern South America has harmed galaxy fish populations.

As the largest species of Pacific Coast salmon, it can weigh up to 56 kg. They have a coil-shaped body and the head is about 20% of the total length. In mature males, the head is even longer. During the breeding season, the male’s jaw changes, which becomes like a hook and prevents the mouth from closing completely. Both males and females have large, sharp teeth in both jaws. The gill rakes are coarse and wide with 10-16 rakers on the lower part and 6-10 on the upper.

The Chinook salmon has a long, narrow fat fin and a centrally located dorsal fin. It has square edges and contains 10-14 main rays. The caudal fin is broad and shallowly split. The pectoral fins are low, slightly pointed and contain 14-17 rays. The anal fins contain 14-19 rays, a property that distinguishes members of the genus Oncorhynchus from other trout.

It is easy to see the difference between females and males when spawning with the help of their main body shape. The females’ heads are smaller and more pointed and rounded at the sides. The males form a crooked, elongated nose, have gaping mouths, enlarged teeth and a body that is strongly compressed laterally.

An adult Chinook salmon can be identified using their black gum tissue next to the lower teeth. An adult Chinook salmon are dark green or bluish on the upper back and silvery on the sides and abdomen. When they swim back to the freshwater, their colors change and they turn golden. The closer they get to the spawning, the darker they become. The young fish are brownish with long transverse dark marks along the sides. As they develop from fry to young fish, their bodies become more silvery. The tail fin develops a black band at this time.

its tail fin. During the mating period, the color of the fish changes and the males form a hump on their backs and their jaws bend and can no longer be closed completely. In most cases, the body of the Chum salmon is silver-colored. The back is darker and has some indistinct dots placed in random places. When the fish are to spawn, the otherwise sivel-colored salmon turn dark olive green. The abdomen also gets darker. On the sides, flame-like patterns of stripes appear, which in the tail end are dark and in the middle violet. The males’ stomach fins turn white on the tip.

When it’s time to breed, the Chum salmon migrate upstream to spawn. They then look for shallow gravel bottoms where they can spawn with the females. After the spawning, they die.

Their main food is crustaceans, squid and other fish.

When the Chum salmon have been planted off, among other places, off Murmansk’s shores in Russia, the latter have been found in the Tana River and Näätämöjoki, where they spawn. The Chum salmon have multiplied in these waters, but it is unclear whether the salmon that come to spawn are young specimens from these rivers, or whether they were born or planted in other watercourses.

The Chum salmon are anadromous fish that live in saltwater but reproduce in freshwater and brackish water. They are usually up to 60 cm long, but there are specimens that have become up to one meter long. The heaviest Chum salmon that have been caught weighed 15.9 kg but usually weigh much less than that. The oldest Chum salmon that is documented was 7 years old. An ordinary Chum salmon lives only for four years and dies after the spawning. As soon as the Chum salmon have reached their sexual maturity, they seek to return to the freshwater to spawn. The spawning takes place at a depth of three meters. The female digs a hole of about one meter in diameter and with a depth of 50 cm before the spawning can begin. The hole is created by the female lying on one side and wagging the tail fin to remove the sand and sludge from the bottom. The female and the male place themselves in the nest and yawn with their mouths. Rapid vibrations cause the eggs and spleen to be released. The female then covers the nest. The males can spawn with several different females and can become aggressive by themselves.

The females can also spawn with several males and therefore build several different nests where the eggs can be fertilized. Within a week, the adult fish have died. Between 700-7000 eggs are fertilized during the two to three egg releases that are made. Usually 300-3500 eggs are released per spawn.

The eggs are only 6.7 mm small and thrive in a water temperature between 8-10 ° C 60 days before hatching. The fry are about 16 mm when the eggs hatch. In the spring, the young fish swim at sea and return 3-4 years later to their exact birthplace. The Chum salmon become sexually mature when they are between 2-4 years old. The fry stay at their birthplace where the spawning took place while the young fish move along the coast.