Brown trout of the Barents and White seas

Very beautiful fish - trout of the Kola Peninsula

Brown trout are found in the lower reaches of the Onega River and its tributary Kozha. There are trout in the Paloi rivers on the eastern coast of Onega Bay; trout live in a number of other rivers and streams of this coast, in particular in the Kotovaya River. Brown trout are or have been found in many reservoirs of the Summer Coast of the White Sea: in the Lopshenga River, in the Golodeikha 1st and 2nd streams, in the Syart River, Lavkata Creek, the Yarenga, Bolshaya and Malaya Rezhma, Syuzma rivers; in the last river by 1930 disappeared. There are trout in several rivers flowing into the Unskaya Bay - Kumzhevoy, Vezhma, Kinzhuga, Luda, Babiya.

Brown trout lives in the rivers Mudyuga, Malaya Torozhma, Zimnyaya Zolotitsa, and other rivers and streams of the Zimny coast of the White Sea. Brown trout are also found in the rivers of the Mezen Bay - Chizhe, Mgla, and are found, although rarely, on the western coast of the Kanin Peninsula - in the Shoina River. In the north of the Kanin Peninsula, brown trout have not been found, but there are to the east - in the rivers of the Czech Bay of the Barents Sea - Pesha, Prishchatinnitsa, Wolonga, Velikaya, Shubnaya, Chernaya and Indiga.

The eastern border of the brown trout range cannot be determined. The local population often refers to brown trout as Arctic char.
Apparently, it was the Arctic char that was mistaken for brown trout on Pechora, Novaya Zemlya and Kolguev Island.
Trout are absent in the basins of large rivers in northeastern Europe - the Northern Dvina, Mezen, and Pechora. Individual specimens of brown trout were caught in the lower reaches of the Northern Dvina and Pechora - perhaps these were individuals of brown trout that entered the rivers for the winter. There is a known case of catching trout in the Pechora Sea.
Brown trout forms a number of subspecies; trout populations in northern Europe are combined into the subspecies Salmo trutta trutta. According to a number of osteological characteristics, the trout of the White Sea basin differs significantly from the Baltic populations of brown trout and, perhaps, deserves to be identified as a separate subspecies.
However, no qualitative genetic differences between brown trout in the White Sea basin and other northern European trout populations were noted, although the populations of this basin are distinguished by a high level of diversity in protein-coding genes.

Ecological morphology of brown trout in the Barents and White Seas

There is no data in the literature on the morphology of brown trout in the Barents and White Seas. The body shape of juvenile brown trout ideally matches its lifestyle. The slab-like, powerful body with a high caudal peduncle allows it to lunge from shelter for prey in fast water. The large head and mouth allow the brown trout to capture relatively large food items. A low number of gill rakers is also associated with relatively large prey sizes.
The results of a comparison of “hatchery” juvenile trout and wild juvenile trout from rivers and streams of the Karelian and Terek shores of the White Sea are indicative. No differences were found in most traits, but brown trout from the Onega fish hatchery had smaller values for the length and height of the head, the height of the anal fin, the lengths of the pectoral and ventral fins, and the greatest body height. Apparently, this is not due to interpopulation differences, but to the lower mobility of the “hatchery” fish; similar features were noted in “hatchery” juveniles of the Black Sea trout.
In addition, brown trout from the Onega fish hatchery have larger eye sizes than wild brown trout; this is apparently due to constant shading in the workshop where this fish was kept. The difference in the size of the upper jaw between the compared samples is explained by different measurement techniques.
Juvenile brown trout exhibit a striking variety of colors. Several elements that make up this feature change at once. Brown trout are characterized by the presence of small black spots all over the body, but their number may vary; sometimes the spots are surrounded by a light rim. Young individuals and maturing residential males have large, oval, dark spots located at regular intervals on the sides of the body (the so-called “pied” spots); these spots are extended from top to bottom and from a distance appear to be stripes. Wild specimens often have numerous small red spots, but in hatcheries these spots are almost always absent. Depending on the illumination and the color of the bottom, the background color varies from dark brown to white; the most common are greenish, steel and olive backgrounds.
During smoltification (that is, preparation for going to sea), the brown trout acquires a silvery color, a more striped body shape and loses its “variegated” spots and small red specks. Subsequently, as the brown trout grows, the color changes little, but before spawning the skin of the spawners darkens again, and large male brown trout have a small “hook” on their lower jaw.
A number of morphological characteristics distinguish brown trout from a closely related species - salmon, or Atlantic salmon (Salmo salar L.). In particular, brown trout have more dark spots on the operculum, a higher caudal peduncle, and a smaller caudal fin notch. However, all these characters are quite plastic, especially in juvenile brown trout.

 

 

Structure of brown trout populations

As mentioned above, in addition to the anadromous (feeding in the sea) form, brown trout forms an estuarine form and a number of residential (feeding in fresh water) forms, often called "trout". Among the residential form of brown trout, males predominate, and among migratory brown trout, females predominate, that is, these two forms in each river are part of a single population.
When comparing brown trout from different sea basins, the age of the ray in the sea increases from west to east, as living conditions worsen. The age of trout migrants on the Karelian coast is 2-4 years, in the Unskaya Bay and on the Tersky coast of the Kola Peninsula - usually 3-5, in the Ponoy River (Kola Peninsula) - 4-7.
In the Vezhma River, rolling juvenile trout had an average length of 19.5 cm (two-year-olds), 23.6 cm (three-year-olds) and 29.6 cm (four-year-olds). The average mass of migrants of different age groups was 72.5, 154.7 and 280 grams, respectively.
Individuals of the migratory form of trout going to spawn in the Wolong River have a length of 45-5 cm and a weight of up to 3 kg, individuals of trout going to wintering have a length of 30-35 cm and a weight of 350-500 g. In Kumzhevoy, the length of those going to winter male trout who spent 3 years in the river and one summer in the sea - 27.0-30.5 (average 28.4) cm, female brown trout of the same age - 25.5-29.0 (average 27.3) cm. Older fish are larger - the length of two males who lived 3 years in the river and two summers in the sea - 38.5 and 40.0 cm, two females who spent 4 years in the river and one summer in the sea - 33.0 and 34.5 cm. In Vezhma, the weight of female trout migrating for the winter is on average 720 g , males - b80 g.
The maximum age of individuals of the residential form of trout from the rivers of the Winter Coast (Mudyuga and Malaya Torozhma) is -4 +, in Mudyuga the average length of fish in this age group is 31 cm, weight - 272 g. Resident male trout in the Malaya Torozhma and Kumzheva rivers mature at the age of 4+ .
In brown trout populations in other areas of the White Sea coast, resident males mature earlier, and the age structure is simplified. Thus, in the tributaries of the Ponoi, male trout mature at the age of 3+, in the streams of the Karelian coast - at the age of 2+ (as an exception - 1+). This may indicate a greater impact of fishing on these populations than on brown trout in the Arkhangelsk region. The genetic structure differs in brown trout populations living in different parts of the White Sea coast, which indicates the existence of homing in this fish. The brown trout population of the Kumzhevaya River, which flows into Unskaya Bay, is especially notable; Perhaps this is due to the significant isolation of the Unskaya Bay from the main waters of the White Sea.

Life cycle of brown trout

Juvenile brown trout live in places with fast currents and the presence of shelters - stones, snags, holes, trees that have fallen into the water. Brown trout especially love places where the core turns into a whirlpool and forms countercurrents. Some young trout remain for their entire lives in rivers and streams, replenishing their living form, and some go to sea. The migration of juvenile trout into the sea occurs in May-June.
The feeding of brown trout occurs in the sea bays and in shallow waters. Already in September-October, brown trout return to rivers and streams for the winter. These individuals are light in color (their popular name is “firefly”). Overwintering of salmon fish in the sea is impossible. Foreign experiments on brown trout revealed that at 2 °C the ability of brown trout to adapt to seawater is reduced. Domestic experiments on salmon have shown that mortality in salt water at temperatures below 1 °C increases sharply, and at temperatures close to 0 °C all experimental fish die.
Judging by observations at Vezhma and Kumzhevoy, trout mature no earlier than after two years of feeding at sea. In Wolonga, ripening trout begin to rise in the second half of July, in Vezhma - in the second half of August. Trout spawning occurs in September-October, its fertility is 2-3 thousand eggs.

The role of brown trout in ecosystems

A study of the trout population of the Mudyuga River showed that the area of spawning and rearing grounds for trout in this river is 30 hectares, and per 100 m2 there are from 6 to 17 specimens of juvenile trout. Thus, this river, which is quite typical for the region, is home to 18-51 thousand young fish. Unfortunately, this is the only such study conducted in the Arkhangelsk region.
However, it can be confidently stated that in a number of streams and small rivers, brown trout predominates in numbers and biomass over other fish species, that is, it is a “key species” of their ecosystems. Rivers and streams dominated by brown trout are called "trout" or "trout" streams.
Judging by the data obtained from studying the populations of White Sea Karelia and the Kola Peninsula, the food items of brown trout are very diverse. Its diet includes almost the entire living population of the reservoir, with the exception of vegetation.
Juvenile brown trout living in rivers and streams feed mainly on invertebrates: caddisfly larvae, stoneflies, midges, chironomid larvae and pupae, mayfly nymphs, bugs, tendipedids, mollusks, leeches, and in the summer - terrestrial insects that have fallen into the water.
In addition, minnow was noted among the food items of juvenile trout. In the small Cherny stream on the Karelian coast, a downstream trout was caught, and a young of the same species was found in its stomach. Brown trout of various sizes can feed on salmon eggs. Obviously, this is caviar that did not get into the spawning mounds and is still doomed to death.
Large river and lake-river trout, mostly piis hidden by fish and can therefore destroy juveniles and smolts of salmon. Juvenile salmon have been observed in the stomachs of fish longer than 16.5 cm. Brown trout can feed on juvenile acclimatized pink salmon Oncorhynchus gorbuscha. The brown trout of the Kola Peninsula have been noted to feed on mouse-like rodents.
In estuaries and at sea, brown trout feed on amphipods, Gammarus oceanicus, juvenile cod fish, sand lance, Ammodytes marinus, threespined stickleback, Gasterosteus aculeatus, herring, Clupea pallasi, smelt, Osmerus mordax. Some wintering trout from the Kumzhevaya River feed on fish.

Predators, parasites and competitors of brown trout

Observations on the Kola Peninsula show that the worst enemy of brown trout in northern waters is pike. It even pursues large fish: a case has been described of a pike eating spawning trout weighing more than 1 kilogram. The antagonism of these species was revealed statistically - when analyzing the structure of the ichthyofauna of small lakes on the Karelian coast of the White Sea, it was shown that the association coefficient for brown trout and pike is negative. Brown trout are not found in pike-inhabited rivers of the Summer Coast of the White Sea.
In the sea, sea hare, or bearded seals, guinea pigs, and possibly harp seals feed on brown trout. However, salmon are not currently listed among the food items of the latter two species; This may be due to a decline in the numbers of these fish.
Juvenile brown trout, like juvenile salmon, serve as hosts for the larvae of the European pearl mussel, Margaritifera margaritifera. These larvae spend the winter on the gills of salmon fish, and then move on to independent life. The pearl mussel is an endangered species, listed in the Red Books of all levels - from international to regional. Brown trout is the only host of pearl mussels in a number of reservoirs of the Onega Peninsula.
It should be noted with alarm that other parasites of brown trout, as well as its bacteria and viruses, have not been studied at all in the region. The lack of parasitological and microbiological monitoring, combined with the growth of salmon aquaculture in the Russian North and neighboring countries, provides all the conditions for outbreaks of dangerous diseases in brown trout.
In addition, the competitive relationships of brown trout with other fish species, including alien salmonids such as rainbow trout and pink salmon, have not been studied in the region. Meanwhile, the spawning of brown trout occurs shortly after the spawning of pink salmon - just during the period when decomposing fish lie on the spawning grounds.
Observations in the basins of the Kereti, Rynda and Zimnyaya Zolotitsa rivers show that juvenile trout live mainly in small channels and streams, and juvenile salmon live in the main riverbed. Similar observations were carried out in the Varzuga and Kachkovka river basins. Competition between juveniles of the two species has been demonstrated in a number of foreign works; It is also shown that when the number of Atlantic salmon in the river decreases, the number of brown trout increases.
Atlantic salmon and brown trout, although morphologically similar, differ well in a number of genetic markers. Using these markers, hybrids of these species were discovered in nature. They were identified, in particular, in the rivers of the Kola Peninsula and northern Karelia, but not in the Arkhangelsk region.
It can be assumed that it is precisely competitive relations with Atlantic salmon that prevent brown trout from populating the basins of large rivers in the extreme northeast of Europe - the Northern Dvina, Mezen, and Pechora. Individuals trying to colonize the shallow rivers of these basins do not find each other and hybridize with Atlantic salmon.
Unfortunately, the relationship between brown trout and Arctic char (Salvelinus alpinus) has not been studied, although Scandinavian studies contain information about the competitive relationships of these species. Meanwhile, the decline in the number of brown trout as they move east occurs in parallel with the increase in the number of Arctic char, which is better adapted to Arctic conditions. It is likely that it is competition with Arctic char that limits the eastward spread of brown trout.

Economic importance of brown trout

Most of the settlements on the shores of the White and Barents Seas are located at the mouths of salmon rivers. However, brown trout populations have always been very important for small groups of people living temporarily or permanently outside villages: fishermen, hunters, reindeer herders, Old Believers, military personnel and geologists. Trout significantly supplement their limited diet, and catching them with a fishing rod adds variety to their harsh life. Consumer fishing for trout is still carried out in all reservoirs inhabited by trout.
The brown trout fishery has apparently never been abundant. During the 20th century, the trout fishery gradually declined. As far as one can judge, this was due not so much to a decrease in the number of brown trout (although cases of disappearance of populations as a result of overfishing are known), but rather to the low profitability of this fishery. The commercial fisherman on the Kumjaz rivers and streams was replaced by a poacher. Sometimes brown trout were simply exterminated, considering them a competitor to salmon. Thus, brown trout were completely removed from the Wolong fishery.
Brown trout is an excellent sport fishing object.
There is a reserve on 4 rivers of the Kola Peninsula, Kharlovka, Litsa, Rynda, Zolotaya, the task is to preserve wild salmon and brown trout, therefore it is allowed on these rivers
Only sport fishing on the “catch and release” principle.
Brown trout is a promising aquaculture object.
Scientists have developed biotechniques for breeding White Sea trout, including modes of keeping spawners and incubating eggs, rearing juveniles, and have successfully conducted experiments on raising brown trout in cages in brackish water. Currently, brown trout are reproduced at the Solzensky and Onega fish hatcheries.

The value of brown trout

Trout meat has beneficial properties, is very tender and tasty. It is absorbed by the human body easier and faster than meat. This fish cannot be called fatty, although there are layers of fat between the muscles of its body in certain places. The average calorie content of all types of brown trout in its raw form is 100-105 kcal/100 g of meat. The product is also valued for the fact that it contains valuable fats for humans, which are very useful for strengthening the cardiovascular system and preventing heart attacks and strokes. It is also a storehouse of vitamins (A, group B, E, PP, D) and minerals: magnesium, zinc phosphorus, selenium, fluorine, potassium, calcium, iron, manganese. Plus 17 amino acids.
Many dishes are prepared from trout. Trout is salted, boiled, fried. All these processes are simple, and trout is prepared quickly and easily.