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influence of a thermal factor on an organism of fishes

Temperature — the major ecological factor, the set of data on its influence on life of animals, in particular pojkilotermnyh (31, 81, 83, 90) is saved up. However almost all available data concern actions postoyojannyh temperatures though in natural conditions are real only peremenyonye.

It was supposed, that action of the last is adequate to what vyyozyvaetsja in the constant temperatures equal on thermal constants kolebljuyoshchimsja, actually it is far not so (43, 44,45,49).

Now at cultivation klarievogo a catfish in UZV podderzhiyovajut a stable temperature mode - 26-28°С within days, that javyoljaetsja in average optimum temperature. At the same time it is known, that during evolution organisms adapted to astatichnoj to an inhabitancy, including for fluctuation of temperature within days (44,47,46,49,56,59).

The basis of industrial cultivation of fish is compounded by optimisation of the temperature mode providing optimum conditions for intensive consumption and an effective utilisation of forages (15, 16, 35).

At fishes, as a rule, the body temperature is almost equal to temperature okruyozhajushchej mediums. Naturally, increase or temperature fall in doyopustimyh for a certain kind of fishes limens invokes the conforming alterations of their ability to live. At rise in temperature raises obyomen materials in this connection oxygen consumption increases, uvelichiyovaetsja search, consumption and nutrition digestion, raises chuvstvitelyonost to toksikantam (40,70, etc.). Temperature decrease conducts to the anatropic

To the processes described above, and excessive refrigerating conducts to cold

(91). Acclimatisation to heats proceeds much faster, than to the low. According to N.S.Stroganov (90) exists small temyoperaturnyj a range in which change of temperature does not render sushcheyostvennogo influence on a metabolism. However it is noted at fishes of the temperatures completely acclimatised in this range. For a carp this range is in limens 26 - 32°С (40, 89).

Influence of temperature on fishes is closely bound to other factors of medium and influences an organism in aggregate with them. At a choice of temperature of water at cultivation of fish in industrial conditions it is necessary uchiyotyvat influence of metabolites of fishes, the expense of oxygen on oxygenation, izmeyonenie ekskretsii ammonium, carbonic acid and pH (5, 8,15, 27, 47,62, 64). MaksiYOmalnyj growth and optimum mastering of nutrition is observed not always at odyonoj and the same temperature. Therefore at cultivation of fish in pools where the temperature mode is regulated, choose compromise level of temperature which provides both a tachyauxesis of fish, and effective mastering of a forage. At temperature above optimum the acquired energy of a forage starts to be spent in great volume not for a mass gain, and on maintenance of ability to live (86).

Last researches of scientists (27, 55) show, that molod evri - stenotermnyh kinds of fishes grows better if the temperature of water of nanosecond stable within days, and fluctuates within an ecological valence of a kind with some frequency and voltage (25±5°С at an o'clock for a carp).

There is an assumption, that in a fluctuating temperature mode skoyorost respirations of fishes goes down, and rate of growth - raises (51). Thus breathing rate decrease, i.e.

reduction of power inputs of fishes, soprovozhdayoetsja more economic use of nutrition on a plastic exchange.

Existence of organisms in astatichnyh conditions is considered biologiyocheskoj norm, and in stable (constants) - its infringement.

Numerous literary data say that being in termogradientnom a field, fishes do not concentrate in any narrow it

Field, and constantly move in wide enough temperature

Range. For example, at Japanese jack mackerel Trachurus japonicus it reaches 10—13°С, at different kinds of smelts — 20—25°С, at molodi Salvelinui natnay - cush — 10—14°С. It is Thus established, that temperature fluctuations in nekoyotorom a range with different frequency characteristics not only not

Worsen, but even considerably enrich growth, power and fiziologicheyoskoe a state of fishes. At any stationary temperatures the oscillation, instant temperature drops or poperemenyonoe a finding of fishes in aquariums with different temperature (49, 54, 55, etc.) is impossible dosyotignut those positive takes of cultivation of fishes what are possible in a variable thermomode with those or other parametres, whether it be sinuyosoidalnaja . That dynamics of temperature influences which is realised for them as a result of spontaneous moving in termogradientnom a field (65) is especially congenial for growth, power and a physiological state of fishes. Obviously, in conditions termolrefsrsntnogo (termoreguljatornogo) behaviour that dynamics of temperature influences which to the greatest degree corresponds to physiological requirements of fishes is carried out. VyYOjavlenie features and parametres of this dynamics with the subsequent vosproyoizvedeniem it in industrial conditions discovers new prospects soyovershenstvovanija biotechnologies ryborazvedenija which is based till now on a principle of the maximum approach of temperatures to the stable values considered as the optimum. However by the scientific researches carried out in last years it has been shown, that the standard representation about an optimality of stable conditions of an inhabitancy requires serious specifications (83). The constance doziyorovki the factor in its any expression does not provide an optimality of medium. Naturally each factor of medium influences organisms in the changeable expression. On the one hand, to some extent izyomenjaetsja an inhabitancy (seasonal, daily fluctuations of abiotic factors), with another - position of organisms constantly varies owing to their passive and awake moving to space. The inhabitancy of alive organisms is dynamical, instead of is static, and to assume, that natural conditions of a habitation negatively influence them hardly

It is fair, since. evoljutsionno organisms are adapted to constant izyomeneniju factors (48; 49).

G.A.Galkovskaja and L.M.Sushchenja (10) in the work devoted to growth of animals at variable temperatures notice, that in conditions kolebayonija the temperature which are not falling outside the limits a tolerant range, nabljuyodaetsja augmentation of specific speed of linear and weight growth, absoljutyonogo a gain, speed of development and true speed of reproduction poyopuljatsy. In modern ecology the given position receives the increasing

Recognition.

In experimental works spent on hexapods was pokazayono, that in the conditions of variable temperatures speed of their development on different

Stages, as a rule above, than in constant conditions (117). SpravedliYOvost above the told confirms a number of the experimental researches spent on some hydrobionts. At action of fluctuations temperayotury G.A.Galkovskaja and L.M.Sushchenja (10) was revealed by an acceleration of growth and faster development dafny (Daphnia sp.). Odum (83) notices, that the temperature fluctuating from 10 to 20°С (at the average temperature equal 15°С), not objayozatelno reacts on an organism the same as constant temperature 15 °s. Parametres of growth of separate individuals and populations in variables termorezhiyomah always differ from the conforming values at average konstantyonoj to temperature. If increase of last always invokes fruitfulness minimisation the variable thermomode leads to an establishment otnoyositelno to higher fruitfulness that has been shown G.A.Galkovskoj and L.M.Sushchenja (10).

Ability to live of organisms which in the nature usually podvergajutyosja to influence of variable temperatures (that takes place in the majority of areas with a temperate climate), it is depressed particulate or is slowed down at influence of constant temperature. So, in the first research in given range SHelford (140) has found, that eggs, larvae and dolls jabyolonnoj fir seed moths in the conditions of the fluctuating temperature educe on 7-8 % faster, than at the constant temperature equal to average temperature in experience. In other experiment Parker (137) by means of a variable temyoperatury managed to accelerate development of eggs of a grasshopper on the average on 38,6 %, and nymphs - on 12 % in comparison with development at constant temperature.

Interesting data have been received at influence research peremenyonoj temperatures on growth rate, a biochemical body composition and fizioloyogicheskoe a state molodi fishes (22, 23, 24, 26, 52, 53, 54, 55, 56, 57, 58, 60, 51, 155). Experiments spent in modes of an oscillation of temperature otyonositelno average values (°s with voltage dt (t+dt) and control konyostantnyh conditions where the temperature was equal to average in a mode ostsilljayotsii (t) and to limens of its changes (t+dt). These data convincingly svidetelstyovujut that t+dt fishes grow in an oscillation mode much faster, than at constant temperature. Simultaneously there were changes of a biochemical body composition of fishes, the maintenance dry veshcheyostva, fat-free dry the residual and lipids increased. In variable tsrmorezhims the physiological state of fishes, in particular blood indicators was enriched also. At temperature fluctuations the  destruction of fishes during them you - decreased

ЗІ

rashchivanija, raised tsrmorezistentnost, is essential decreased vayoriabelnost body masses in comparison with the control at a constant tempeyorature (23, 25). There is an opinion, that the variable thermomode in diapazoyone temperatures of ability to live of a kind promotes minimisation energetiyocheskih organism expenditure. In this range at surplus of nutrition variable reyozhim promotes redistribution of the acquired energy in favour of a gain and, hence, to augmentation of pure efficacyy of growth (29,48,65).

The voltage of fluctuations of temperature and speed of its change, optimalyonye for growth, are species-specific, at stsnotermnyh fishes they much more low, than at the eurythermal. Degree of this distinction correlates with that what is observed in the term of natural localities of fishes. The acceleration of growth of fishes in pereyomennom a thermomode contradicts representation about an optimum as to a point

On an ecological valence scale.

Temperature fluctuations with defined amyoplitudoj and frequency stimulate growth in some range molodi a carp. Average daily growth rate in this mode approximately on 20 % above, than average in konyotrole at the constant temperatures corresponding inferior, top and

To average to values ostsillirujushchih. A daily ration in conditions ostsilljayotsii on 15 % more low, than in the control. This difference having high statistiyocheskuju reliability, as well as decrease on 2-15 % of consumption of oxygen ryyobami, testify to increase of efficacyy of converting of the nutrition, invoked by temperature fluctuations. In applied aspect an oscillation

Growth of fishes will allow to accelerate temperatures, to receive considerable economy of a forage and to raise efficacyy of its use on growth of fish.

1.3.

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A source: Kovalyov Konstantin Viktorovich. Technological aspects of growing catfish (Clarias gariepinus) in a hatchery with closed-loop water supply (UZV). Thesis for the degree of candidate of agricultural sciences. Moscow - 2006.

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