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Современные наукоемкие технологии
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WAYS OF RE-ACCLIMATIZATION OF THE POPULATIONS OF THE BLACK SEA SALMON AND THE PROSPECTS OF THEIR RESTORATION

Zyuzina O.N. Sushkov V.A. Reshetnikov S.I. Studentsova N.A.
Natural reproduction of the Black sea salmon trout in most of the reservoirs is restricted by a small area of natural spawning-grounds, absence of the necessary condiditions for the effective spawning conditions. Nowadays the situation is changing; pool managements FSM «Glavrybvodа» are in charge of the reproduction. Scientifically grounded monitoring is necessary for obtaining the best specimens and avoiding choking up of natural reservoirs. It is expedient to make up a data bank and a single system of genetic and population supervision over the forming of the uterine flocks and also a control over the condition of populations in natural reservoirs, and monitoring of their sexual and age structure, condition of the forage reserve and accepting capacity of reservoirs.

After the analysis of the materials that we received and the materials that were published by other specialists, the observation over the condition of the produced whitebait and establishing of the effectiveness of the works that are being performed should be organized.

It is expedient to carry out analytical works on the Caspian salmon as well.

As a result of our research we have received information about the composition of ichthyofauna, number and biomass of fish, plankton and benthos in different parts of the rivers; there have been defined competitive species of the Black Sea salmon trout; we´ve calculated production and hydrobionts, on the basis of which there has been defined the accepting capacity of the rivers Mzimta and Shahe according to the whitebait, produced by the Adler industrial experimental salmon fish-farm.

The received results are used for restoration of the number of the salmon trout in the Black Sea and defining necessary amounts of whitebait to be produced in natural conditions, by at the Adler industrial experimental salmon fish factory and other industrial works, producing the whitebait of the Black Sea salmon.

The Black Sea salmon trout (Salmo trutta labrax) - is the most valuable specimen of the salmon family (Salmonidae), inhabiting the reservoirs of the Azov-Black Sea basin. Its economic importance is conditioned by the high gustatory quality of meat; its ecological role is connected with the occupying niche of a predator of the highest trophic level. During the last decades the supplies of the Black sea salmon trout and therefore its catches have been invariably decreasing, which entailed ascribing to this subspecies a status of the protected taxon on the regional level as well as on All-Russian and international levels. The Black Sea salmon trout is included into the Red Book of the Krasnodar region, The Red book of the Russian Federation and the European Red List.

Up till now most of the rivers of the Black Sea coast have lost their role as spawning reservoirs for the salmon trout. In the situation that has formed the most acceptable way of the restoration of the numbers of this subspecies in the region is its artificial reproduction with the following letting out of the whitebait into the rivers, the most suitable for catadrome migration and the subsequent return of the salmon trout after the fattening in the Black Sea for spawning. Biocoenoses of the Black Sea rivers are little examined according to the forage reserve and ichtyofauna as well as according to the conditions of the fattening and reproduction of the salmon trout itself.

Rivers of the Black Sea coast of the northwestern Caucasus from Anapa to Tuapse flow in the zone of deciduous and beech woods; and from Tuapse to the southern borders of the Krasnodar region- in the area of thick wet forests of the kolkhidskiy-type. The length of the rivers here is small; it is conditioned by the close location of the Big Caucasus slope. Out of 114 rivers falling into the Black Sea, the length only of the Mzimta, the Shahe, and the Psou is above 50 km. They originate high in the mountains and they are typically mountainous with strong current and characteristically low temperature, numerous rapids and waterfalls. In the mouth areas they are calmer and make up considerable cones of drifts. Most part of the year the rivers are not full, in summer they lose their connection with the sea due to their low water level, and only in the period of rains and thawing of snows the level of water in them rises. From hydrological point the Black Sea coast of the region considerably differs from the Kuban basin and near Azov Rivers. It is divided into numerous catchment basins. The area of the catchment of the rivers Mzimta, Psou, Shahe is about 400 square kilometres.

Water routine of the Black Sea Rivers differs in high freshets from rains and thawing snows in cold part of the year and fixed low levels from May to October. General mineralization of the water in these rivers fluctuates from 50 mg/l (the river Mzimta in its upper current) to 940 mg/l (the river Gostagaj) and higher. But small and medium mineralization (not over 500 mg/l) is characteristic of the majority of the rivers.

The Mzimta- is the largest river of all falling into the Black Sea on the territory of the Krasnodar region. The average monthly temperature of the water varies from +2,8ºC (February) to +12,1ºC (August); however it is not more than +5-6ºC in winter-spring time and only in the end of summer it rises up to +11-13ºC. Many springs falling into the river and being places of spawning for the anadromous trout and salmon trout, and also the inhabitations for the whitebait, are characterized by the almost constant water temperature of +10-12ºC during in the year, which is optimal for this species.

The effective reproduction of the salmon trout in the river Mzimta is hampered by the Krasnopolyanskay hydroelectric power station with the storage pool of the daily regulation of flow, which blocks access for the anadromous sires to the main spawning grounds. Hydrologic routine of the remained spawning grounds is extremely unfavourable because of the daily fluctuations of the water level up to 0,5 meters; it negatively influences not only the effectiveness of reproduction but the condition of the forage reserve for the whitebait. Other negative factors are the annual levelling of the riverbed along the Adler-line during the periods of the sires´ motion and joining of the contaminating flows from the Adler trout industry.

The Black Sea salmon (salmon trout) - Salmo trutta labrax (Pallas, 1814), salmon order (Salmoniformes), salmon family (Salmonidae) are anadromous fish coming for the spawning into the Kuban river and its tributaries. The beginning of the spawning motion is in February, its height is in April-May, its end is in June. It reaches sexual puberty at the age of 4 years. The whitebait lives in the river for 2-4 years, and then slides into the sea for fattening. In the sea it feeds on small fish and to a smaller degree on crustacea. In the river the whitebait eats water grubs of the insects and air insects.

Nowadays economical importance is not big. The Black Sea salmon trout needs to be protected. It is in the Red book of the Russian Federation; its category is number one - species, which is under the threat of extinction.

The Black Sea salmon or the Black Sea salmon trout (Salmo trutta labrax Pallas, 1814) refers to the rare and disappearing species of fish of the Black Sea basin. In the past its natural habitat covered the whole coast of the Black Sea: the Crimea, Caucasus, Anatoliyskoye seacoast, Dneprovsko-Bugskiy estuary, Berezanskiy estuary, the seacoast of Bulgaria and Romania, the delta of the Danube, the Azov sea. It used to enter into the rivers, ascending along the Dnepr to Kremenchug, along the Danube-on 700 km, along the Don- higher than Pavlovsk.

Lately the area of habitation of the Black Sea salmon has considerably narrowed. Extinction of many populations of this specimen is conditioned by the intensive catch and worsening of the natural reproduction conditions. The life cycle of the salmon is closely connected with the rivers; therefore many authors think that the main reason for the low numbers of the Black Sea trout is also the absence of the large rivers on the Black Sea coast of the Caucasus, where its mass reproduction could happen.

Nowadays in Krasnodar region only some of the rivers: the Mzimta, the Shahe, the Psezuapse, and the Psou, kept their importance in reproduction of the anadromous form of the Black Sea salmon.

Defining the accepting capacity of the Black Sea coast rivers according to the Black Sea salmon in the first place supposes the study of the peculiarities of the nourishment of this subspecies, its food competitors, including char, and also the forage reserve of these rivers. However, literary data on these questions are rather meagre.

The accepting capacity of the Black Sea rivers according to the salmon trout is defined not only by the nourishment peculiarities of the whitebait of this species, presence of the food competitors and the forage reserve of these rivers but also by the peculiarities of the behaviour and distribution of the salmon trout in the river. The data about the area of the individual territory differ even according to one and the same authors. Using for the calculations the minimal quantity of 2 meters on one fry we have determined that the river Mzimta can accept up to 350 thousand of the comparatively big whitebait. With the moving in of the fry of the younger age groups the amount of the production can double.

To advantage of the increasing amount of the young fish of the salmon trout production speaks the opinion that the compression of the river population leads to the speeding and strengthening of the descent and therefore to the less density of the river population and to the increasing at its expense the salmon flocks in the sea, which considerably enhances perspectives of the reproduction of its stock.

Basing on the data that one not sexually pubescent specimen of the salmon trout needs 2 meters of the individual territory in its river period of life; its maximal number can be 5000 specimens/ha. However living in the river char (according to our data its average season number in year 2003 was 760 specimens/ha) acting as a competitor for the territory decreases the possible number of the salmon trout on one hectare of the area by 4240 specimens at the same time salmon trout uses about 70% of the river area and this reduces the area of the fattening-growing parts by approximately 150 ha. Hence it follows that the accepting capacity of the river Mzimta according to the whitebait (two-year-old) of the salmon trout is 510 000 specimens a year.

In connection with this it is necessary to take into account the competition for the territory between the salmon trout and char, which is numerous in the river Shahe. According to our information its average season number in year 2003 was 1850 specimens/ha. Consequently the maximal number of the produced salmon trout will be reduced by this very quantity and will be 3150 specimens/ha.

Taking into consideration the area of the fattening-growing parts which make up about 150 ha in the river Mzimta, the accepting capacity of the river is 510 000 of the one-year-old salmon trout (or two-year-old) a year.

The calculation of the approximate capacity of the river Shahe according to the young fish of the Black Sea salmon trout showed that the main factor limiting its numbers in the river is not the forage reserve but the area of the individual territory and competition with the char, restricting the upper limit of the whitebait density in this river by 3150 specimens/ha. Taking into account the area of the fattening-growing parts which make up about 100 ha in the river Shahe, the accepting capacity of the river is 315 000 of the one-year-old (or two-year-old) salmon trout a year.

On the basis of the complex analysis of the ecological situation, the system of the measures, the fulfilment of which will contribute to its improvement and stabilization, is suggested.

Information gathered on the main rivers of the Black and Caspian basins, which characterizes the number, ichtyomass, speed of growth and other biological indices of the major marketable fish, lets us calculate the general admissible catch of fish which guarantees the keeping of the reproductive ability of the fish population.

At present time the mathematical model on calculating the optimal quantity of the whitebait and the terms of the letting out of the artificially raised fish into the Black and Caspian Sea rivers is being developed; besides the possibility of the laying in and storing of the sires for getting the descendants and their using for the letting out of the artificially raised fish into the Black and Caspian basins is being examined; the terms of the restoration of the number of these valuable fish species and the possibility of their using as the objects of fishery will be determined.


Библиографическая ссылка

Zyuzina O.N., Sushkov V.A., Reshetnikov S.I., Studentsova N.A. WAYS OF RE-ACCLIMATIZATION OF THE POPULATIONS OF THE BLACK SEA SALMON AND THE PROSPECTS OF THEIR RESTORATION // Современные наукоемкие технологии. – 2005. – № 7. – С. 35-37;
URL: http://top-technologies.ru/ru/article/view?id=23372 (дата обращения: 26.05.2020).

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