Chinook is a large fish belonging to the salmon family. Its meat and caviar are considered valuable, because it is actively bred in some countries with a suitable climate. But in the habitat, in the Far East, it remains less and less. Although the species as a whole is not threatened, as the American population remains stable.
Origin of the species and description
Ray-finned fish appeared almost 400 million years ago ago, after which they began to gradually spread across the planet, their species diversity gradually expanded. But at first this happened at a slow pace, and only by the Triassic period did a clade of teleosts appear, which also includes salmonids.
At the beginning of the Cretaceous period, the first herring-like ones appeared – they acted as the initial form for salmonids. Regarding the time of occurrence of the latter, scientists disagree. According to popular opinion, they appeared during the Cretaceous period, when there was an active evolution of bony fish.
Video: Chinook salmon
However, the first reliable finds of fossil salmon belong to a later time: at the beginning of the Eocene, a small freshwater fish from among them already lived on the planet. Thus, the difficulty here lies only in determining whether this ancestor of modern salmonids became the first form, or if there were others before it.
Unfortunately, there are no fossil finds that could shed light on further evolution over the next few tens of millions of years. Apparently, ancient salmonids were not widespread and lived in conditions that did not contribute to the preservation of their fossil remains.
And only starting from 24 million years BC there are a large number of fossils indicating the appearance of new species of salmon, including the chinooks. Gradually, there are more and more of them, finally, in layers aged 5 million years, almost every modern species can already be found. Chinook received a scientific description in 1792, made by Yu. Walbaum. In Latin, its name is Oncorhynchus tshawytscha.
Appearance and Features
Chinook is the largest salmon species in the Pacific Ocean. Representatives of the American population grow up to 150 cm, and in Kamchatka there are individuals over 180 cm, weighing more than 60 kg. Such cases are relatively rare, but the average chinook grows to almost a meter.
Even despite their size in the sea, this fish can be difficult to spot: the dark green back camouflages it well in the water. The belly is lighter, up to white. The body is covered with rounded scales. The fins on the belly are located farther from the head than in other freshwater fish. During spawning, the appearance of the chinook salmon changes, like that of other salmon: it turns red, and the back darkens. But still, it is inferior in the brightness of the wedding dress to pink salmon or chum salmon.
Also, from the external features of the fish, one can distinguish:
- long body;
- from the sides the fish is compressed;
- small black spots go along the upper part of the body;
- the head section is large relative to the rest of the body;
- large mouth;
- small eyes;
- a pair of features unique to this species – gill membranes in its representatives by 15, and the gums of the lower jaw are black.
Interesting fact: The name sounds so unusual because it was given by the Itelmens. In their language, it was pronounced as “chovuicha”. In America, this fish is called chinook, like an Indian tribe, or king salmon, that is, king salmon.
Where does the chinook live?
It is found both on the eastern coast of the Pacific Ocean and on the western coast, loves cool waters. In Asia, it lives mainly in Kamchatka – in the Bolshoi River and tributaries. It can rarely be found in other Far Eastern rivers south to the Amur, and north to Anadyr.
The second important area is located in North America. Most Chinook is found in its northern part: in the rivers flowing in Alaska and Canada, large shoals go in the rivers of Washington State, located near the northern border of the United States. But further south, it is also common, up to California.
Outside of its natural range, Chinook is artificially bred: for example, it lives in special farms in the Great Lakes, the water and climate of which are well suited to it. The rivers of New Zealand became another place of active breeding. It was successfully introduced into wildlife in Patagonia 40 years ago. Since then, the population has grown strongly, it is allowed to be caught in Chile and Argentina.
In rivers, it prefers deep places with uneven bottoms, likes to stay close to various snags used as shelters. Often swims in the mouths of rivers, prefers places rich in vegetation. Likes to frolic in a fast current. Although the Chinook salmon is a freshwater fish, it still spends a considerable part of its life cycle in the sea. A lot of them keep close to rivers, in bays, but there is no pattern in this – other individuals swim far into the ocean. It lives close to the surface – Chinook salmon cannot be found deeper than 30 meters.
Now you know where Chinook fish lives. Let's see what she eats.
What does Chinook eat?
The diet varies greatly depending on whether the chinook is in the river or in the sea.
In the first case, it includes:
- young fish;
Juvenile Chinook salmon mainly feed on plankton, as well as insects and their larvae. Grown up individuals, not disdaining the above, nevertheless, mostly switch to a diet of small fish. Both young and adult chinook salmon love to eat caviar – often anglers use it as a bait, chinook salmon also bites well on other animals listed earlier.
In the sea it feeds on:
- fish ;
The size of Chinook salmon prey can be very different: for young ones, the menu includes mesoplankton and macroplankton, that is, the living creatures are very small. But still, smaller salmon are more likely to feed on it. Even young Chinook salmon feed more on fish or shrimp. And the adult becomes a predator, dangerous even for medium-sized fish, such as herring or sardine, while she continues to eat small things too. She is a very active hunter and quickly builds up her mass while at sea.
Interesting fact: Among the extinct fish related to chinook, there is such an amazing one as saber-toothed salmon. He was very large – up to 3 meters in length, and weighing up to 220 kg, and had awesome fangs. But at the same time, according to scientists, he did not lead a predatory lifestyle, but simply filtered water for food – fangs served as decoration during the mating season.
Peculiarities of character and lifestyle
The way of life of Chinook salmon strongly depends on what stage it is at – first of all, it is determined by its size, and where it lives, in the river or in the sea.
Several stages can be distinguished, at each of which the life of this fish has its own characteristics:
- the birth in the river, development and growth during the first months or years;
- leaving for salt water and life in them;
- return to the river to spawn.
If the third stage is short and after it the fish dies, then the first two and their differences should be analyzed in more detail. Fry appear in fast-flowing rivers, where there are fewer predators who want to eat them, but there is also little food for them. In these turbulent waters, fry frolic in flocks for the first time of their lives, usually for several months.
At first this is the best place for them, but when they grow up a little, they swim from a tributary to a large river, or downstream. They need more food, and in calmer waters they find it, but there are also more predators in them. In large rivers, Chinook salmon can spend quite a bit of time – a few months, or a couple of years.
Often, at the same time, the fish gradually move closer to the mouth, but even individuals that have already grown up and are ready to enter the salt waters are still quite small – they gain the vast majority of their mass in the sea, where the conditions are best for them. There they spend from a year to 8 years, and all this time they grow rapidly until the time comes to return to the river to spawn. Due to such a difference in the timing of feeding, there is also a big difference in the weight of the fish caught: in the same place, sometimes you can catch both a small chinook salmon weighing a kilogram, and a very large fish that will pull all 30. It’s just that the first one came out of the sea in the first year, and the second lived there for 7-9 years.
Previously, it was even believed that the smallest males, also called mushers, do not go out to sea at all, but the researchers found that this is not so, they just stay there for a short time and do not leave the coastal zone. Large fish can make very long journeys, swimming in the depths of the northern part of the Pacific Ocean, they move away from the coast at a distance of up to 3-4 thousand kilometers.
The climate factor has a strong influence on the duration of feeding. In recent decades, Chinook salmon habitats have become warmer, as a result, they do not migrate over such long distances as during cold periods. Therefore, more fish return each year to spawn – with a smaller average size even though they are better fed.
Social structure and reproduction
They live alone in the sea and gather together only when it is time to spawn. It is in schools that they enter the rivers, which is why it is so convenient for bears and other predators to catch them. In the Asian population, spawning time comes in the last weeks of May or June, and can last until the end of summer. In the US, it falls on the last months of the year.
After entering the river to spawn, the fish no longer feeds, but only moves up. In some cases, you don’t have to swim very far, and you need to climb only a few hundred kilometers. In others, the path of the Chinook salmon turns out to be very long – for example, along the Amur river system, sometimes you have to overcome 4,000 km. In the Asian population, most fish spawn in the Bolshoi River and its basin, in Kamchatka. There, at this time, both animals and people are waiting for her. It is easy to see where the fish swim to spawn: there are so many of them that it may seem as if the river itself is made up of fish, while Chinook salmon often jump out of the water to overcome obstacles.
Arriving at the spawning site, the females knock out holes with the help of their tails, where they spawn. After that, the males fertilize her – they keep 5-10 near each female, and these are both large, and there are very small mushers. Previously, it was believed that the latter spoil the fish – the same small caviar is hatched from the eggs fertilized by them. But this is wrong: scientists managed to establish that the size of the offspring does not depend on the size of the male.
The eggs are large, delicious. About 10,000 are deposited at once by each female: some of them find themselves in unfavorable conditions, others are eaten by animals, and the fry have a hard time – therefore, such a large supply is fully justified. But the parents themselves expend too much energy during spawning, which is why they die within 7-15 days after it.
Natural enemies of chinook salmon
Most of the dangers threaten eggs and fry. Even despite the fact that Chinook goes to spawn in safer upper reaches, they can be the prey of predatory fish, not only large, but also quite small too. They are also hunted by gulls and other birds of prey that feed on fish.
Not averse to eating them and various aquatic mammals like the otter. The latter can catch already grown fish, as long as it does not become too large for it. The otter is able to cope even with spawning Chinook salmon, if it has not been in the sea for long and weighs within a couple of kilograms. Fish of approximately the same parameters are also of interest to large birds of prey, like the big merganser – quite large they are beyond their strength. But bears are able to keep any, even the largest individual: when salmon go to spawn, these predators often wait for them right in the water and deftly snatch them out of it.
For bears, this is the best time, especially since different species go to spawn one after another and the time for such an abundant supply of fish can last for months, and in some rivers even most of the year. Due to the fact that predators are just waiting for the fish to swim to spawn, this time is very dangerous for chinook salmon – there is a big risk not to swim to the upper reaches of the rivers.
The sea is much less dangerous for them, because chinook is a large fish, and most of the marine predators are too tough for it. But still, the beluga, killer whale, and also some pinnipeds can hunt for it.
Interesting fact: To spawn, the chinook does not just return to places similar to those where she was born – she swims to exactly the same place.
Population and species status
The Chinook salmon population in Russia declined significantly during the 20th century, and the main reason for this was overfishing. Its taste qualities are highly valued, it is actively supplied abroad, and poaching is widespread, which makes it difficult to regulate the population. Chinook suffers from poachers more than other salmon, both because of their large size and because they are the first to spawn. As a result, in some rivers of the Far East, red fish, and chinook in particular, disappeared altogether.
Therefore, in Kamchatka, where the largest number of this fish spawns, it can be industrially harvested only as bycatch, and then only off the eastern coast of the peninsula. The permitted catch of chinook salmon 40-50 years ago was about 5,000 tons, but gradually decreased to 200 tons. It is more difficult to estimate how much of this fish is caught by poachers – in any case, the scale of illegal fishing has decreased significantly both due to the fact that the Chinook salmon itself has become smaller and due to stricter protection. Nevertheless, the decline in the population continues – Chinook is now very rare outside of Kamchatka in Asia.
At the same time, the fish breeds well, and the restoration of its population, if the problem with poachers is solved, can occur in just a few decades: every year, 850,000 fry are released from the Malkinsky fish hatchery alone, and in the absence of poachers, many more of them could survive to spawn. This is also shown by the American population: it is at a stable level despite the fact that fishing is allowed in America and Canada and more Chinook is harvested. It's just that the problem with poachers is far from being so acute there, so the fish breeds successfully.
The extermination of chinook salmon, as well as red fish in general, is a big threat to the Far East, whose natural resources are rapidly depleting. Due to poaching, populations of many species were on the verge of survival, so it became necessary to breed some artificially. Chinook is a wonderful fish, it is very important not to let it disappear.