Business idea - crayfish

Aeration ponds for breeding crayfish

In all bodies of water, especially in aquariums, it is very important aeration of water, which is produced with the help of special hydraulic devices. They improve the circulation of water within the water body, her contact with the atmospheric air, which has a beneficial effect on the aquatic environment: completely stops the formation of hydrogen sulphide zone, considerably decreases the amount of oxygen-free area at the depth of the pond, is the mixing of water, which results in enhanced reproduction of invertebrates that serve food for crayfish. Therefore, solving the question of the density of settlement pond, swimming pool or the aquarium, we must take into account the ratio of the surface area of the water to the depth of the reservoir and the presence of aerators - devices for the enrichment of water with oxygen.
Oxygen has a great influence on the basic living functions of aquatic animals, in particular, on their consumption of food. So, in the presence of the water from 6 to 8 mg/l of oxygen (72-100% of saturation at a temperature of 22 degrees C) the intensity of consumption of feed crayfish constant and normal, but with the decrease of the content in the water of the gas it gradually decreases inversely proportional to the concentration of oxygen. When the oxygen concentration of 2 mg/l eating crayfish is only one-third of its consumption in conditions of complete saturation of water with oxygen. This is especially useful to remember when breeding crayfish in various categories of water bodies, to reduce the performance overhead of forage in the winter period when the deterioration of oxygen regime and reducing the temperature of the water. The main factors of formation of the oxygen regime of the ponds are the intensity of solar radiation, the rate of photosynthesis of phytoplankton and higher plants, the degree of consumption of the oxygen in the water hydrobionts, sediment and wind speed.

Methods of aeration of water

For the aeration of water in the ponds of the best ways are spraying water in the atmosphere or feed the air into the water through pipes or hoses with the help of the compressor. Of particular importance is the airing of the bodies of water, fed by artesian wells, near-bottom and keys in standing body of ponds of water, depleted of oxygen. Electro-pneumatic the unit consists of the compressor with electric motor capacity of 4 Kw and guns, connected to the compressor by means of the flexible rubber hose. Guns are a usual metal or plastic pipes with a few rows of holes with a diameter of up to 2-3 mm, located along the pipe to a distance of 120-150 mm from each other. The pipe is laid in the bottom layers of the water. Discharged air compressor under pressure of 3-4 atmospheres, comes in sprays and through small holes comes out, of small bubbles rising to the surface, filling the water of oxygen and preventing the formation of ice cover. For this purpose you can use, for example, the compressor type of CO-7a, giving the air pressure of 6 kg/cm2.

The efficiency of pneumatic aerators determined by the size of formed at the outlet of the diffuser and bubbles of the immersion depth guns. The scheme of aeration of water in the pond with the pneumatic compressor conditions with air aerator has shown, that in the depth of 6.9 and 12 m compressor capacity was equal to respectively 5.5 and 7.0% in recalculation on standard terms. In the winter time for the elimination of death in reservoirs it is possible to recommend the following techniques: water pumped to the surface of ice, then drains into the drilled holes in it, or air is injected under the ice with the help of the hose. However, the effectiveness of such methods, as a rule, is not high. In areas where electrical network are far from the place of installation of aerators, there is a real opportunity to simplify the solution of this set through the acquisition of a pneumatic wind-power plants of the type "Whirlwind". The main nodes of such wind-power plants are two- or three paddle the wind-wheel with a diameter of 4 m with automatic regulator of capacity and speed; four cavitary membrane (the devil-piston) compressor operating without lubrication system; automatic orientation on the mount turning wind wheel in the direction of the wind; the tower is the height of 5 m from the mechanism of forced start and stop the air handling unit.
Instead of welded metal tower you can use a wooden pole, or a tube support. The principle of operation of the unit the following: wind wheel, which was placed on the compressor shaft, rotates with a frequency of 300 rpm and spends the growing power of the compression of the air sucked out of the atmosphere through the filter element. Under the pressure of the air enters the tower, which is at the same time receiver-drive, from which it can be served at any pneumatic device, in particular in distributor aerator. From the energy point of view it is important to emphasize that the primary energy consumption of the aeration installation occurs in winter and spring, when most needed aeration of water. In the summer of wind generator can be used for other purposes, for example, for pumping water, irrigation of small plots, etc. In the basins of-nurseries and aquariums aeration of water is even more necessary than in the ponds. In nature oxygen gets into the water through the surface and in the allocation of this gas water plants. In the ponds of the surface was quite big and the small. A tingle of excitement from the breeze already causes mixing of oxygen with water, and with a strong even more.
The solubility of oxygen in water is much greater than that of nitrogen. The ratio of these gases in the air 1:4 with water 1:2. The upper layer is saturated with oxygen, is constantly in motion, and gradually the whole thickness of the water is saturated with this gas.В aquarium between the water column and surface area of a significant discrepancy. Here the surface of the water is less than the thickness of the water, so in the aquarium at the natural mixing goes much less oxygen than in the natural body of water. So you need to take artificial measures, that in a tank of oxygen in the water was enough. For these purposes aquariums are also equipped with the devices for the aeration of water, but, of course, for these water bodies are used less powerful compressors. A description of the compressors and guns to him, we will not, because you can buy them at pet stores.

The quality of the water.

When the settlement of the pond crawfish on the plot it is necessary to remember, that they are sensitive to the quality of water, which must be fresh, transparent, and its surface not be unduly covered with floating plants. The water should not "bloom " (flowering of water is caused by excessive growth of single-celled algae). Can't stand and eventually become ill river crayfish, when in the water for long periods are boards, of wood and other debris. The oxygen content in the water should be not less than 5-6 mg/l, the reaction of environment (Ph) - in the range of 7.0-8.5. Usually in the warm period of the year, the water in the pool has a temperature of 16 to 18 degrees C. The water in the pond should be fresh or contain a small admixture of mineral salts. Fresh water is called the natural water containing salts very little in comparison with sea water. On one litre of fresh water falls 1-2 grams of different salts, as per litre ocean - 35 grams. From salt water composition depend life processes in aquatic plants and animals. However, the chemical composition of water in the rivers varies. For the reader who is familiar with the course of chemistry, given table 5, which shows the content of the most common ions of salts and gases.
Composition of the dissolved in water salts in different rivers different, so catching crayfish for the settlement of the new pond should produce as possible from the water with the same content of salt, and fill with water of the same composition. It is known that water is hard and soft. Hard water contains dissolved salts, unlike soft, in large quantities. In just poured in the pond, swimming pool or the aquarium water can not produce crayfish. You need to wait for some time while interaction is established between water, soil and water plants. Just poured in the reservoir water from a foreign source via a while cloudy from many developed in her bacteria and then gradually brightens due to the activity of various kinds of infusoria, determining microfauna artificial reservoirs. Such water with organically developed mikrofaunas can be considered suitable for settling ponds crawfish.
The hardness of the water depends on the presence in it of dissolved salts of calcium and magnesium: it is determined by the total concentration of their ions in the water. Water with hardness from 0 to 10 degrees is a soft, from 11 to 18 degrees- average hardness, from 18 to 30 degrees and above very tough. Aquatic animals have a certain area of rigidity, usually in the range from 3 up to 15 oc. Some snails and river crabs do not live in soft water - their shells or shell in it are destroyed. Concentration of hydrogen ions (Ph) is also an important characteristic of the water. Hydrogen indicator shows the concentration of hydrogen ions, is closely connected with the chemical composition of water, in particular with the content of carbon dioxide, carbon mono- and hydrocarbons. Ph is an important characteristic of the quality of water in the ponds, where divorce river crayfish. For their activity (supply, growth and reproduction) the most favorable neutral or slightly alkaline reaction of water (Ph of 7.0-8.5). The measurement of Ph pond water can be carried out colorimetric (the most simple) and a potentiometric method. In the first case, the change in color of the indicator that has been added to the water, and compare with specially calibrated color scale (tetratest).
As an indicator can be specially prepared paper. Soaked in water strip of paper compared to the corresponding colored values of Ph tetratest. The second method is based on direct measurement using a special instrument. Thus, before populate the new pond crawfish, a person must prepare him: pour pond water, planting aquatic plants, which feed on crabs, after some time, when the water will take the necessary quality, catch crayfish in the other body of water and release them into the new pond. The best ponds are water bodies with developed thickets of aquatic plants in the form of belts on the shores of, sites or individual fields of water buckwheat, potamogeton, rogolistnik, uruti, 'hara. The optimal temperature of the water for the crayfish is considered to be 17-20 DEGREES. However, there is an opinion that volos yuzhny poorly tolerate temperatures above 25 C, and in the cold waters lags behind in growth. In practice, in other favorable conditions dilution with water temperatures of up to 24 C allows you to speed up the metamorphosis, which opens up a certain prospects for reduction of time of growing crayfish to marketable size.
The quality of the river basin, in addition to the general enabling environment, is determined by the areas of the coastal zone, where the cancer finds a refuge and power. As one of the first on the bottom of the pond you can put snags, stones, pieces of slate or pipe, where the crayfish will hide in the daytime. Flat, shallow pools of water not suitable for volos cancer, but it is suitable for less demanding in respect of shelters long-toed cancer. In the cold winter, the pond should not freeze to the bottom, so in the middle of it is desirable to have a depth of 10 m to crayfish could find a place, where no water turns to ice.