Breeding crayfish at home. Sales and marketing of a crayfish farming business. Breeding crayfish in an aquarium or pool

Of course, everyone has heard about crayfish living in rivers around the world, in Russia and Germany and other countries. Moreover, everyone knows not only what an ordinary live crayfish looks like, but they have also eaten it. But not many people know that crayfish are different in all countries. This is due to the conditions of their existence and what they have to eat.

Our crayfish that live in the waters of the Don, Volga or Dnieper, even the largest ones, are considered relatively small, but the largest crayfish are the inhabitants of the rivers of Tasmania. It’s hard to imagine, but some of the largest individuals weigh more than 5 kilograms, and they grow up to 0.8 m in length! See what this breed of cancer looks like in the photo.

But, unfortunately, such individuals are now rare even in those parts. This happens due to the fact that their living conditions have deteriorated significantly. But the existing individuals are quite huge by our standards; you will never find specimens weighing about two kilograms in the rivers of the Don, Volga, Dnieper or abroad in France or Germany.

The crayfish that live in our rivers are typical representatives of crustaceans. They are very demanding on water quality, so they can be a kind of living indicator of the cleanliness of a reservoir. Simply put, if there are crayfish in a river, stream, lake or headquarters, then you can swim and fish in such a place.

The basis of the diet of crayfish is vegetation, not only living plants, but even fallen leaves. They eagerly eat dead fish, and if they are lucky, even live ones.

Active at night, they prefer to spend daylight hours hiding in burrows (which they can dig on their own) or in other shelters.

They search for food mainly by smell; their corresponding organs of touch are well developed. They can find the corpses of fish or other living creatures at a fairly large distance.

General information

During the Jurassic period (about 130 million years ago), many animals appeared on Earth, including crayfish, which subsequently quickly populated bodies of water throughout the globe. They feel most comfortable in reservoirs that are at least three meters deep with ten-meter depressions. Best Temperature water in summer time about twenty degrees.

River crayfish is not an entirely accurate name, since they live not only in rivers, but also in other bodies of fresh water, hence a more accurate name suggests itself - freshwater crayfish.

Habitat

Crayfish, as we have already said, are very demanding of their habitat. The first condition is that the water should not be salty, otherwise their reproduction becomes impossible due to a number of circumstances.

For these crustaceans great importance has sufficient oxygen content in water, at least 5 mg/liter. Acidity is also important, which should not be too high. The water must be clean. Crayfish can live in almost any body of fresh water, but their favorite habitat is rivers.

The bottom in the habitat of the crayfish must be hard and silt-free; only under these circumstances can they organize the necessary shelter for themselves.

A rocky bottom may also be suitable, since they can calmly settle under stones, without even digging holes, which they prefer to do near coastal holes or on coastal slopes. As a rule, at the boundary between a hard and soft bottom. Smart crayfish try to make the passage into the hole as long as possible, often about a meter or more, and the hole itself can be located under a fallen tree, tree rhizomes or under stones.

Crayfish burrows are never large and are dug based on the size of the crayfish itself, which makes it much easier for them to protect themselves from attacks by their larger counterparts.

It is quite difficult to pull Cancer out of its shelter; it clings very tightly to its walls with its claws. You can determine that there is crayfish in the hole by looking at the fresh soil near the entrance.

Crayfish live at depths from 50 cm to 3 meters. The best places for burrows, as a rule, are captured by large males, while the worst places go to small males and females. Young individuals usually try to stick to shallow water, often close to the shore, under pebbles, leaves and twigs.

As everyone knows, crayfish are inveterate hermits and everyone has some kind of shelter, which he has to protect, first of all, from his own relatives. During the day, crayfish hide in shelters, closing the entrance to them with their claws. In case of any threat, they quickly retreat deeper into the hole.

To search for food, crayfish go out at dusk, and if the sky is cloudy, they can go out earlier. Typically, crayfish move in the water at night with their claws extended forward. In case of danger, it swims back very quickly, striking strongly with its tail.

It is generally accepted that crayfish stick to one place. But this is a mistaken opinion. An experiment was carried out and marked individuals ended up in gear one hundred or even two hundred meters from the place where they were released. This suggests that these are quite mobile intelligent creatures.

Crayfish breeds

The success of a crayfish breeding business, especially at the initial stage, will depend on the competent selection of female breeds. each has its own characteristics. The most interesting of which are:

Crayfish are different and the required breed can be purchased at special farms for breeding. They are usually sold by weight, but in some cases individually. The price for one female can range from 5 to 100 dollars, depending on the breed. $5 per female.

Video “Crayfish Behavior”

This video shows different breeds of crayfish that are bred in home aquariums. Look how these smart creatures behave.

For breeding, crayfish are sometimes caught in local reservoirs, but in this case they have to wait a long time for puberty.

Sizes of crayfish and how long they grow

The speed at which crayfish grow depends on the temperature and composition of the water, as well as on the food and the number of individuals per 1 square meter. reservoir The growth rate in different bodies of water may be different. However, even in the same body of water, growth rates may differ. In this case, much depends not only on water and feeding, but on the age of the crayfish. In the 1st and 2nd summers of life, females and males grow almost equally. However, already from the end of the 3rd summer, males are larger than females. Experiments were carried out in southern Finland and the following facts were established. The length of the crayfish by the end of the 1st summer reached 1.4-2.2 cm, by the end of the 2nd from 2.5 to 4 centimeters and by the end of the 3rd from 4.5 to 6 centimeters. It is worth knowing that according to the regulations in Finland, Germany, Russia and other countries, the minimum size allowed for catching must be at least 10 centimeters, i.e. males are six to seven years old, females are one to eight years old. Under favorable conditions (suitable temperature, sufficient amount of food) they can grow to the permitted 10 centimeters several years earlier, and in unfavorable conditions, a year or two later.

The world of crayfish is quite interesting and has attracted the attention of scientists in past centuries.

The question is often asked, to what size crayfish can grow, i.e. how many centimeters is the maximum length of their body? Here it is appropriate to go back a hundred years and turn to the research of the German fish farming advisor Brofeldt, according to which the following facts are presented. For example, in the town of Kangasala it was not uncommon to see individuals longer than 16 centimeters, but after a few years they began to be found much less frequently. It is also known that specimens of twelve to thirteen centimeters caught in the last century were considered average. Such facts may make us distrustful, but crayfish do not have to be large.

In the fifties of the last century, the Seura magazine organized competitions to see who could catch the largest crayfish in three summer months. The winner was the participant who was able to catch the crayfish, the body length of which was 17.5 centimeters, and if measured to the end of the claw - 28.3 centimeters, the weight of the champion was 165 grams. Some other facts regarding the winner are also given. First, he only had one claw and second, it was a female!

The next largest male was 16.5 centimeters long, but the length of his claws was 29.9 centimeters and his weight was 225 grams.

There are also other evidence of caught crayfish, the length of which exceeded 17 centimeters. But this is very rare. It should be noted that, according to the data of the Estonian researcher Jarvekulgin, males are more than sixteen centimeters and weighing 150 grams, and females are more than twelve weighing about eighty grams - a rarity. Undoubtedly, the female caught in Finland can be classified as a giant.

The question about the age of crayfish or how long crayfish live is difficult to answer because... There is no exact method for determining their age. The lifespan of some crayfish has to be determined by comparing age categories or categories of crayfish of similar length. As a result, it is impossible to determine with great accuracy the age of individual large specimens. However, there is evidence that some individuals lived to the age of twenty years or even more.

Perhaps in the future a method will be discovered and we will accurately determine how many years a particular cancer has lived.

Crayfish in Germany

The successful breeding of crayfish in Lake Rottach-speicher (Germany), the water surface of which is about 300 hectares, is indicative. It is worth noting that it was filled only in 1990, when 10 thousand crayfish fingerlings were released along with various types of fish. The entrepreneur who rented this lake began to harvest a large harvest of large males within two years and now has a solid business with volumes of about 50 tons. Some of the individuals that were released in 1990 were caught only ten years later, some weighing up to 250 grams.

It was in Germany that significant success was achieved in the field of crayfish breeding. The beginning was made in 1985 at one of the Bavarian enterprises specializing in crayfish breeding. A special installation with a closed water supply was created and successfully used. Its capabilities are not limited to the hatching of crayfish; it is successfully used for breeding young of the year. This installation allows hatching more than 150 thousand fry and 35 thousand fingerlings during the year. And although crayfish eggs are naturally fertilized at this plant, artificial insemination is also used in other German plants.

In this regard, great success has been achieved by specialists from one of the companies in Eversee. Initially, they borrowed the experience of Finnish crayfish farmers in the field of artificial insemination. Subsequently, a special installation was created to fertilize the eggs. It works according to the following scheme. The eggs of the females are scraped off and placed in baskets, in which they are continuously washed with water, simulating the process of natural fertilization under the female’s tail. This made it possible to almost double the fertilization rate of eggs compared to natural ones. It was also noticed that the larvae obtained in this way are more resilient than after hatching in females.

Almost all crayfish farmers in Germany are united in a union promoting the protection of crayfish in Europe. The Union often holds various forums and conferences where important issues are discussed and cancer farmers exchange experiences. In 2007, the 3rd forum dedicated to the protection of crayfish was held in Austria and a special booklet was published, in which not only the most interesting materials, but also important and useful recommendations on cancer farming are given.

Why are there few crayfish in our country?

To answer this question, you need to know that live crayfish are a natural indicator of the pollution of a reservoir. Crayfish often die from discharges that can only be detected in laboratory conditions. There are many false versions that have no basis, since in this case not only crayfish, but also fish, and in some cases people, would die. In order to determine why living crayfish die, you first need to know where exactly this happened. For example, it was the Don, Seversky Donets or another river and what enterprises were located there. Consistently in this way you can establish the source.

However, crayfish can die not only from chemical pollution. For example, ships are sailing along the Don, which could well have introduced microorganisms that caused the death of crayfish. There are many factors that can lead to the death of crayfish. It is also very bad that restoration of the population requires at least 5 years under favorable conditions. We already had a similar precedent in the nineties. At that time, crayfish in the Don River almost completely disappeared and then appeared only ten years later. In recent years, the situation on the Don has been more or less stable.

This video shows how blue and common crayfish that live in the waters of the Don or another river can be successfully grown in a small farm.

Industrial cultivation of crayfish is not popular among domestic businessmen. Large enterprises working in the field of aquaculture try to avoid this direction, since the long payback period does not justify significant investments in setting up a crayfish farm. As a result, the high demand for products is partially satisfied by catching crustaceans in natural reservoirs, however, the size and quality of these individuals leave much to be desired.

In such a situation, one can consider breeding crayfish at home as a business that brings in a small but stable profit. In addition, a farm of this scale does not require intensive care: the entrepreneur’s daily tasks are limited to feeding the pets once and checking the water quality. Finally, modern equipment makes it possible to grow not only the familiar crayfish, but also larger, heat-loving species, the high market value of which serves as an additional incentive for beginners.

Business Features

The simplest way to organize a business is considered to be breeding crayfish in a pond: to set up a farm, an entrepreneur just needs to rent or purchase a plot of land with a natural reservoir. The pond basin is cleared of debris, populated with young animals, and after 5–6 years a self-reproducing population is obtained.

Of course, one cannot expect any significant income in this case: the simplified method completely excludes the possibility of controlling the parameters that are most important for the growth of the herd, which include the chemical composition and temperature of the water, feeding ration and stocking density. Therefore, experienced farmers prefer intensive crayfish breeding technologies, which involve the construction of artificial reservoirs with a partially or fully controlled environment. The advantages of this method are obvious:

• An entrepreneur can receive his first profit in 12–18 months;
• Individuals grow much faster, and within a year they reach a weight of 100–150 g;
• When placing aquariums or swimming pools in heated rooms, you can buy heat-loving crayfish species that are highly productive for breeding at home;
• Thanks to control over reproduction and incubation, the survival rate of young animals increases to 85–90%.

The business of growing crayfish is characterized by certain advantages and disadvantages: in order to draw a conclusion about the feasibility of implementing this idea, the entrepreneur must consider them in their entirety, taking into account, first of all, factors that can turn into an insurmountable obstacle for him. Listing positive sides, it is necessary to mention that:

• There are several methods for breeding crayfish at home for sale, and some of them are quite loyal to the amount of investment;
• During the work process, the entrepreneur’s expenses are limited to payment utilities and purchase of feed at the rate of 0.5 kg per individual per year;
• Caring for crayfish requires virtually no time or physical effort;
• An entrepreneur need not be afraid of competition, since in Russia few farmers are involved in the implementation of the business idea of ​​crayfish breeding;
• Demand for products remains high regardless of the season.

The main disadvantage of this type of activity is considered to be the slow growth of crayfish: representatives of common river species reach marketable sizes within several years. Besides:

• Setting up a crayfish breeding farm using intensive technologies requires significant investment;
• In open reservoirs, at water temperatures below 17°C, crustaceans stop growing and hibernate, so the business is seasonal;
• Regardless of the method of cultivation and the type of crayfish, a return on investment should not be expected earlier than in 3-4 years.

Species for breeding

An entrepreneur who wants to buy live crayfish for breeding must take into account factors such as the growth rate and marketable size of individuals, consumer demand and climatic features of the region - the domestic buyer perceives some quite edible crustaceans exclusively as a decoration for the aquarium, and keeping heat-loving species in the conditions of the Middle Zone only possible in closed heated tanks. In general, the following are suitable for growing using intensive methods:

• Broad-clawed crayfish. It is distinguished by a fleshy body up to 20 cm long and large claws. It prefers reservoirs with a rocky bottom, heated to a temperature of 16–22°C, and therefore feels good in artificial pools. Currently this type is endangered: you can buy crayfish for breeding only in nurseries Leningrad region, Baltic States or Belarus;
• Narrow-fingered crayfish. The most common species in Russia, characterized by high fertility: every year the female lays at least 300 eggs. The body length of a male at the age of five reaches 16–18 cm and weighs 120–150 g. Crayfish prefer sandy and clayey soils suitable for building burrows, which helps them adapt to the conditions of open artificial ponds;
• Blue Cuban cancer. It has a calm, peaceful character, as a result of which it rarely attacks relatives and fish. At quality nutrition this species grows to 8–12 cm in less than a year. It prefers moderately warm waters with a temperature of 23–25°C, so it takes root well in aquariums and pools, where each pair requires about 20 liters of water. To buy blue crayfish for breeding, you need to go to a large pet store;
• Marble cancer. It lives in well-heated reservoirs with a temperature of 20–28°C, where it grows up to 15 cm in two to three years. This species has no sexual division - each crayfish can simultaneously lay and fertilize up to 300 eggs. It calmly tolerates a planting density of up to 20 individuals per 100 liters of water, as it has a peaceful character. You can buy crayfish fry and adults for breeding in online stores or from private breeders;
• Australian red claw crayfish. A heat-loving species that prefers water bodies with a temperature of 21–28°C. It is distinguished by its fleshiness up to 30% of body weight, fertility and growth rate - within a year, young animals reach a weight of 120–150 g with a body length of 12–15 cm. Thanks to their calm nature, they feel good at a stocking density of up to 25 pcs/m². You can buy Australian crayfish for breeding in nurseries in Astrakhan and Krasnodar region.

Breeding methods

Popular methods for keeping crustaceans can be divided into two groups: the first involves the creation of identical natural conditions for breeding crayfish, while the second focuses exclusively on achieving maximum productivity through the formation of an artificial environment with optimal parameters for the development of the population.

Open ponds

Breeding crayfish in a pond is characterized by high labor intensity at the initial stage: it is necessary to dig out several reservoirs with flat walls on the site and equip them with water circulation systems. The area of ​​each can be 0.01–0.1 hectares with a depth of up to two meters. The bottom should be lined with clay, covered with sheets of polypropylene or plastic film, and then a layer of sand and stones should be poured on top, under which the crayfish can build their shelters.

In the future, the entrepreneur’s tasks are reduced to periodic monitoring of water quality, timely aeration and algae removal. It is also recommended to regularly feed pets, since with high planting densities, the volume of natural food supply may be insufficient. When listing other requirements for artificial ponds, it is necessary to mention that:

• In order to avoid the death of livestock, reservoirs should under no circumstances completely freeze, so in cold climates it is advisable to deepen them to 3.5–4 m;
• To prevent flowering and growth of microalgae, up to 30% of the total water volume must be replaced every two weeks;
• Drainage ditches should be dug along the perimeter of the ponds, as well as strengthening the shoreline and creating shade by planting grass and trees.

Advantages of the method:

• The cost of maintaining the reservoir is minimal;
• The water in the ponds is partially aerated and purified through natural processes;
• The development of a natural food supply allows you to save on the maintenance of crayfish.

Flaws:

• In open water, crayfish grow quite slowly;
• Acceptable planting density is no more than 5–6 pcs/m²;
• It is impossible to control the temperature and chemical composition of the water;
• To fill the ponds you need a constant source of water supply;
• It is necessary to think over ways to drain ponds - you cannot simply pour hundreds of tons of water into the garden or yard;
• It is difficult to remove young animals after breeding broodstock;
• In winter, crayfish do not gain weight.

Aquariums

You can start breeding crayfish in an aquarium not only in the village, but also in urban conditions - just choose a room in which the temperature does not drop below 19–21°C. Here, several wide aquariums with a capacity of about 250 liters each are installed, filled with soil and plants, and then equipped with microclimate and water quality control systems.

As a business, breeding crayfish for sale in an aquarium involves large-scale investments - the cost of a tank equipped with everything necessary is comparable to the cost of equipping a pond with an area of ​​90–100 m². Therefore, this method is used mainly for keeping ornamental species, or for raising fry before planting in open ponds.

Advantages of the method:

• Availability of an automated control system;
• Ability to maintain any given temperature;
• Thanks to the heating of water, crayfish do not go to winter;
• The permissible planting density is up to 30 pcs/m².

Flaws:

• High cost of equipment per unit of production;
• Aquariums need to be cleaned regularly, water and plants changed.

RAS installations

Special equipment for breeding crayfish is more cost-effective and practical than ponds: for example, under natural conditions, individuals reach marketable weight in 3–4 years, while in closed water supply installations this period is halved. Moreover, the ability to regulate the parameters of the aquatic environment in a RAS makes it possible to breed Australian crayfish and other productive species that grow to the required size in just 12–18 months.

Commercially available installations are equipped with equipment that makes it possible to purify water from impurities and waste residues, subject it to disinfection, heat it and saturate it with oxygen. They are placed in any insulated rooms where the temperature does not drop below 10°C: in a home farm, basements or sheds can be used as such.

Advantages of the method:

• Water consumption is limited to the initial filling of the crayfish tanks and minor level adjustments after evaporation;
• The growth rate of pets does not depend on the season and outside temperature;
• The operation of the installation is fully automated;
• The vital activity of the herd is perfectly controlled - females can be removed for spawning, fry can be sorted and crayfish can be kept separately for sale;
• The planting density of adults is up to 25 pcs/m², fry - up to 250 pcs/m².

Flaws:

• High cost of equipment;
• The air humidity in the room increases significantly;
• The operation of the installation is accompanied by the consumption of electricity.

Farm in the basement

The advantages of intensive crayfish breeding technologies fully compensate for the costs associated with setting up a farm: the productivity of a RAS installation with a capacity of 2 m³ is equivalent to the productivity of an open pond with an area of ​​80 m². In a small insulated basement 5x10 m, you can place five such installations and by breeding Australian red-clawed crayfish, you can annually obtain at least 120–130 kg of products. In the process of preparing the premises, the following must be taken into account:

• The basement must be dry, free from fungus and mold, with concrete floors and walls. When pests are detected, it is necessary to use sulfur bombs and aerosol insecticides. It should be noted that crayfish can be introduced into pools only 12–14 days after treatment;
• For active life, crayfish practically do not need light. In the basement it is enough to install several lamps at the rate of 5 W/m² and organize the duration of daylight within 10–11 hours;
• The room must be equipped with an exhaust ventilation system, since the evaporation of water from the pools increases the humidity level.

Farm equipment

A farmer planning to buy equipment for breeding crayfish should know that fish tanks with a capacity of 2–3 m³ with high walls are not suitable for these purposes: their filling is accompanied by excessive water consumption, and operation is inconvenient due to the great depth. Therefore, for growing crayfish, special RAS are used, which are a frame with six polypropylene pools installed on it in three tiers. In this case, five containers with dimensions of 2000x830x250 are used for keeping the herd, and the sixth contains:

• Circulation pump;
• Biological filter;
• Ultraviolet sterilizer lamp;
• Heating elements;
• Compressor for aeration.

An entrepreneur who has at his disposal five such three-tier RAS installations can organize the work of the farm as follows:

• One pool is designed to support a broodstock of 30 animals (20 females and 10 males) with a stocking density of 18–20 pcs./m²;
• Four tanks are used for seeding females for the incubation period and subsequent rearing of fry at a stocking density of 200–250 pcs./m²;
• Four installations with five tanks each are used to maintain a commercial herd of 830 animals with a stocking density of 25 pcs./m².

Farm arrangement

Name	price, rub.	Qty	Amount, rub.
Three-tier RAS	116000	5	580000
Oximeter	12800	1	12800
Universal measuring device	1400	1	1400
Shelters for fry	2,9	900	2610
Shelters for young animals	7,7	900	6930
Shelters for broodstock	12,5	50	625
Feeders	150	50	7500
Lamp	1200	5	6000
Exhaust fan	3200	1	3200
electronic scales	2000	1	2000
Total:			623065

Considering the functional purpose of the equipment, it should be mentioned that:

• An oximeter is used to measure the degree of oxygen saturation of water;
• The universal measuring device is a conductometer, salinity meter and thermometer combined in one housing;
• Shelters for adult crayfish and fry can be made from propylene pipes, cut into pieces 15–20 cm long;
• Electronic scales are used to weigh feed and control the weight of livestock.

Breeding conditions and technology

Studying the species characteristics of crustaceans, one can notice that breeding Australian crayfish at home seems to be more profitable: firstly, they grow much faster than the well-known narrow-toed crayfish, and secondly, their cost on the market is three times higher than the price of crayfish. The step-by-step technology for growing the red claw species is as follows:

• Purchased fry or adults are planted in RAS tanks;
• Crayfish are raised to reproductive age;
• Females with eggs are placed in free pools;
• After a month, the fry are left in incubators, and the females are returned to the herd;
• After two months, the grown young animals are distributed among the tanks.

After a year, the crayfish reach a weight of 130–150 g. Some of them are selected for the tribe, and the rest are sold wholesale or retail.

To create conditions comfortable for crayfish, it is necessary to adhere to the recommended values ​​at all stages the most important parameters aquatic environment:

Chemical composition of water

Purchasing young animals

When choosing where to buy crayfish for breeding, novice entrepreneurs often go to the supermarket or the nearest market, or collect fishing gear and try to catch specimens for the breeding stock in the nearest body of water. Meanwhile, these methods can hardly be considered effective:

• Crayfish caught in wildlife, grow very slowly;
• The natural environment is not sterile, as a result of which there is a danger of catching infected individuals;
• When delivering to retail outlets, carriers are not bothered by creating ideal conditions for crayfish, which leads to drying out of the gills and oxygen starvation;
• Stores most often receive rejected specimens that are not suitable for breeding.

Therefore, when searching for suitable suppliers, it is better to contact private breeders and specialized nurseries: here it is advisable not only to make sure that crayfish do not have diseases, but also to get advice regarding their breeding.

You can buy Australian crayfish and representatives of other heat-loving species for breeding at a price of 120 rubles per adult, while the cost of an ordinary narrow-clawed crayfish is 400–500 rubles per kilogram. In the process of forming a herd, you should adhere to a 2:1 proportion - in other words, the number of females should be twice the number of males.

Feeding

When using intensive technologies, there is usually no natural food supply in the pools, and therefore, in a business plan for crayfish breeding, it is necessary to provide for the costs associated with the purchase of feed. To formulate the diet of animals in an artificial environment, use:

• Crushed corn, wheat, barley;
• Minced fish and meat, bone meal;
• Boiled mashed potatoes or carrots;
• Steamed hay;
• Oak or beech leaves as a natural antiseptic;
• Larvae, insects, worms.

However, with a large population, it is more advisable to use ready-made mixed feed - as practice shows, crayfish willingly eat mixtures intended for salmon and carp fish. The daily feeding rate is 2% of body weight for commercial stock and 5–6% for spawning females: thus, the annual supply of food for raising crayfish is determined at the rate of 530–550 g for each individual.

Composition of feed for crayfish

Ingredient	For young animals	For adults
Wheat bran	–	25 g
Broken wheat	–	15 g
Sunflower meal	15 g	20 g
Soybean meal	15 g	20 g
Fish flour	35 g	5 g
Feed yeast	10 g	5 g
Bone flour	–	5 g
Powdered milk	20 g	5 g
Sunflower oil	5 g	2 g
Premix for fish	1 g	1 g

Reproduction and growth

In nature, crayfish mate in the fall, after which the female sticks the eggs under her tail and carries them during the winter. In heated reservoirs this pause is absent, so the breeding cycle lasts two months instead of six.

Depending on the species, the clutch volume is 100–500 eggs, most of of which dies. As a result, 40–60 larvae are born, which quickly gain weight, and within a month they acquire the ability to feed on their own. Under natural conditions, the survival rate of fry usually does not exceed 15–20%, while in RAS tanks, with abundant nutrition, up to 90% of the brood can be preserved.

During growth and development, crustaceans molt periodically - up to six times in the first year of life, and then two to three times annually. Due to the fact that this process does not occur simultaneously for the entire population, both smaller and larger individuals simultaneously find themselves in the pool at different stages of growth. To avoid cannibalism, it is recommended to place the latter in other tanks.

The molting stage itself is very dangerous for cancer: being left without a shell, covering gills and teeth, it becomes completely defenseless against aggressive relatives. Therefore, molting individuals tend to make a hole for themselves or find another shelter: the farm owner must provide them with this opportunity by placing pipe scraps, clay shards and stones on the bottom of the aquarium.

Paperwork

Unlike other types of agricultural business, the activities of a crayfish farm within the framework of private household plots can only be carried out when selling products to friends, since the sale of crayfish on the market or to other entrepreneurs requires the issuance of appropriate certificates. Therefore, the work of the enterprise should be legalized in the form of an individual entrepreneur or peasant farm; To avoid paying insurance premiums and completing unnecessary reporting, it is better to submit documents to the Federal Tax Service after receiving the catch.

From a legal point of view, crayfish farming can be presented as one of the branches of agriculture in the field of aquaculture. This means that the owner of a cancer farm is allowed to choose the Unified Agricultural Tax as a tax system at a rate of 6% of the total profit.

In addition, in accordance with legislation and sanitary requirements, retail stores and catering establishments purchasing products from a farmer may require such accompanying documentation as:

• Sanitary passport of the vehicle used for transporting crayfish (can be obtained by contacting the veterinary station);
• Declaration of conformity (issued by Rosselkhoznadzor);
• Form No. 2 (can be obtained after providing samples of water and products to the veterinary service department);
• Certificate of conformity GOST 50380-2005 (issued by both Rosselkhoznadzor and private certification bodies).

Investments

Organizing the work of a large enterprise requires knowledge, which can be acquired as a result of practical activities and studying the experience of other entrepreneurs - for example, by watching the video “Raising crayfish at home”:

Video on the topic

To organize the operation of the farm, the entrepreneur must first prepare the premises and install the required number of RAS units here. Then you should resolve the issue of food supply and buy crayfish for breeding: prices for adult representatives of productive species are in the range of 90–120 rubles per head.

The main expenses during the year will be associated with replenishing the stock of feed and paying for electricity: each installation consumes up to 700 Wh during initial heating of water and 250–300 Wh during operation.

Annual expenses

Expected earnings

Crayfish farming as a business - profitable or not? To determine the profitability of a crayfish farm, it is necessary to estimate the annual production volumes: for an enterprise using five RAS installations of the type described above, after an annual feeding, the output will be at least 830 individuals with a marketable weight within 150 g. Accordingly, the total weight of the herd will reach 124.5 kg.

Australian crayfish of the indicated sizes on the market is valued at 1,500–1,600 rubles per kilogram when sold live: the farmer’s total income in this case will be 199,200 rubles. Taking into account the amount of current expenses, we can calculate the annual profitability and payback period of the enterprise:

Economic parameters of a crayfish farm

Conclusion

Obviously, it is hardly advisable to consider raising a small population of crayfish as a source of main income: as calculations show, to make a profit of over 1 million rubles per year, an entrepreneur must have a whole complex of RAS installations with a total area of ​​200 m² or a pond farm with an area of ​​up to 1600 m² .

The second task that a beginning farmer must solve is organizing sales: despite the high level of demand, only large stores have equipment for selling crayfish, and only a few catering establishments include dishes from them on the menu. On entry level This problem is solved by selling products to familiar and referred private clients, but increasing production volumes requires a qualitatively different approach. The solution may be close cooperation with fish shops or opening your own retail outlet, complemented by a full-fledged virtual representative office.
43 voted. Grade: 4,53 out of 5)

Such an unusual business as growing and breeding crayfish at home provides a stable income due to the demand for the product. Large fishing enterprises do not specialize in such a unique business, because the investment will not pay off in the near future. Selling large quantities is not easy, and the products are perishable. The delicacy product is in demand among a very limited circle of people.

For beginning entrepreneurs, it is recommended to buy the first batch of crayfish of a certain breed, the offspring of which will serve as a start for the business. Starting a crayfish farm does not require huge investments, but you need to be patient, because they take a very long time to grow.

Peculiarities of crayfish breeding require the presence of reservoirs or containers with water. It should be taken into account that invertebrates hibernate during cold periods and their growth slows down.

Types of crayfish for breeding

When choosing arthropods, you should consider characteristics breeds and capabilities. It is recommended to purchase only fertilized females. They are sold by live weight, sometimes by the piece. They purchase from cancer farms, individuals and industrial companies.

A formed and complete broodstock can be found from professionals, farmers who have been breeding crayfish for a long time. To obtain a ton of crayfish, you should purchase about 100 kg of fertilized females. You shouldn't expect profit earlier than in a year.

The best crayfish for breeding at home:

• European broad-toed;
• long-toed European;
• Australian;
• Cuban blue;
• marble.

Australian red claw crayfish

Breeding the Australian red claw crayfish is considered to be the most cost-effective and promising today, because adult specimens have multiple advantages:

• unpretentiousness;
• fast growth rates;
• heavy weight.

In their natural environment, they reach a weight of 2 kg in 3-4 years. The investment pays off within 2 years.

The Cuban blue crayfish is not bred for its outstanding size, but rather for its exotic color and rapid maturation. The arthropod grows in six months and is unpretentious in food.

Mexican dwarf crayfish are bred, rather, for aquarists. The miniature size of arthropods does not allow calculating the profitability of a business; their weight and size are too small.

Breeding marbled crayfish makes the task easier because they are unisexual. And fertilization does not require the presence of both a female and a male. In addition, individuals grow to quite decent sizes after a year.

Lake crayfish is considered the most profitable option for growing. Unpretentious arthropods grow to quite large sizes in a short time, so they are popular all over the world. Lake crayfish fry develop in females within 2 months.

Crayfish breeding technology

The popularity of crayfish farms is gaining momentum, thanks to minimal investment and high demand for products. As a business, it already exists all over the world and is considered quite promising. In Russian realities, it is quite possible to establish a cancer farm on your own.

To reduce investments, novice entrepreneurs catch crayfish in rivers and ponds. This is certainly simpler and cheaper, but it is worth considering that the growth of such individuals may be much less, and the profitability of the business will not be high.

At home, arthropods are bred in natural or artificial ponds, aquariums, swimming pools, and other containers. The industry offers a variety of installation options specifically designed for such businesses. Swimming pools are dug in the territories of private houses, and a shelter is built on top to create comfortable conditions.

Necessary conditions for breeding crayfish:

• heated room;
• the presence of several containers;
• aeration (circulation and water purification);
• balanced diet;
• providing the container with oxygen.

Crayfish raised for sale must have a standard weight for the breed and a healthy appearance.

Reference! The survival rate of fry, even in artificial reservoirs, is very low, no more than 20-25%.

The temperature regime is maintained so that the process of reproduction and growth is continuous.

Breeding crayfish in a pond

Breeding crayfish in a pond at the dacha is the most budget-friendly option, especially if the pond is located in close proximity and there is constant access to it. Due to the lack of a natural source of water, ponds are dug on the site. The area of ​​such a reservoir is calculated for the planned population. The arrangement provides for a plumbing system to renew water and a sandy and rocky bottom for nesting crayfish.

Nutrition is the most important and necessary point in organizing a cancer farm. Crayfish eat little and are not picky about food. The basis of the diet of arthropods is a variety of representatives of aquatic fauna. Arthropods happily eat small fish, eggs and fry. Therefore, it is recommended, if there is a natural reservoir, to breed crayfish in a pond with fish.

Breeding crayfish in an aquarium

In an aquarium at home, crayfish are bred in rooms where there is a heating system. Recommended area – at least 80-100 square meters. It is necessary to have electricity supply and working plumbing.

People living outside the city are recommended to place aquariums on their property, right on the street. The containers are dug into the ground at approximately 3/4 of the height. The initial result of the “cancer” business directly depends on the choice of materials and the quality of the aquarium.

Primary requirements:

• minimum volume – 250 l;;
• optimal water hardness – 10-12;
• height of aquariums – no more than 1 m;
• the widest possible bottom.

Advice! It is preferable to choose plastic aquariums as a material.

First you need to purchase several aquariums for trial testing and determination suitable method breeding. As the business expands and the number of livestock increases, increase the number of containers as necessary. The water in the aquarium should always be within the range - from +17 to +21, for this you purchase special devices and equipment.

Breeding crayfish in RAS

The most advantageous method is the use of closed water supply units (RAS). Main advantages:

• saving space;
• saving water;
• independence from weather conditions;
• monitoring the vital activity and functioning of the system;
• simplified waste removal system.

RAS consists of a whole complex of equipment and devices that require considerable financial investments. In the southern regions, equipment is used only for raising juveniles; in the northern regions, crayfish are bred in RAS all year round.

Video:

Breeding crayfish in the pool

• volume of the future reservoir;
• installation of water supply for aeration;
• waterproofing;
• depth of the pool for breeding crayfish (at least 80-90 cm).

To create a habitat that is familiar and convenient for crayfish, the following is placed in a chaotic manner at the bottom of the pool:

• broken dishes;
• plastic pipe cuttings;
• various containers - jugs, jars, pots;
• bricks with holes.

Such improvised “burrows” will attract arthropods.

To ensure a stable temperature, the pool should be located indoors. Hangars and sheds are being built from brick, plastic, and wood.

In order to obtain offspring, 2 females and 1 male are placed in one container. After the reproduction process is completed, the male crayfish is placed in the pool for further feeding. As soon as the fry become independent, they will be placed in a pool for further fattening.

In garages where it is planned to place a “crayfish” farm, it is necessary to equip a basement. The walls are disinfected, and in order to save space, shelving for aquariums is installed. Or they build a full-fledged swimming pool with a plumbing system and a temperature regulator. You can purchase a polypropylene pool and dig it in the garage.

There must be at least two containers: for keeping and breeding adults and for young animals. It is imperative to take care of the heating system.

What to feed crayfish

Thanks to their developed sense of smell, crayfish in natural conditions easily find rotten fish and feed on them with pleasure. At home breeding It is worth taking care of additional nutrition. If possible, add to the diet of young animals:

• cyclops;
• Daphnia;
• larvae;
• snails;
• aquatic worms;
• fish fry.

Reference! Young animals readily eat boiled vegetables and minced meat.

As they grow, their diet becomes more varied. And so that crayfish, prone to cannibalism, do not eat each other, they are given:

• vegetables;
• meat;
• fish;
• bread;
• cake;
• frogs.

You can also add fish feed, chalk and proteins, bloodworms and earthworms to the food for breeding crayfish. Be sure to make sure that there is nothing left in the feeders until the next meal.

Crayfish farm

You can create your own crayfish farm even on a small plot and at minimal cost. The main condition is compliance with care standards and recommendations. This type of business is not very popular in Russia, but is quite successful in other countries of the world. This is due to differences in consumer demands. A perishable product must be sold as quickly as possible.

Organizing a farm is possible in almost any conditions. The larger the volumes, the more profitable the production. The business idea is to make a profit with minimal costs. This is especially true for people living in rural areas near ponds or having the opportunity to rent ponds.

Crayfish for sale are raised for at least 1-1.5 years. Sales timing and volumes depend on the breed and conditions. Having received your broodstock, you can already count on a return on your investment in almost a year.

Industrial breeding of crayfish will require considerable investment: you need equipment and premises where several pools or containers can be placed at once. Climate control and water supply system are also important.

Containers for breeding crayfish should be large, and the number of arthropods in them should also be controlled. If the crayfish are crowded, they will also begin to eat each other. This also applies to young animals, which are kept in separate tanks.

With the right choice of breed, the availability of equipment, balanced feed and a stable sales market, crayfish breeding can become a successful business.

Such a business idea does not require large expenses and can bring a stable income for six months - from May to October. The seasonal nature of this income is perhaps the only drawback of such a business. Before starting this business, it is necessary to determine the demand in the market - whether it exists in principle, and if it exists, then how great it is. Of course, you can breed crayfish only for your own consumption, but it is much more pleasant to not only enjoy the final product, but also receive stable income for a long time.

What is the demand in the market?

To start with crayfish farming as a business, it is advisable to call restaurants and supermarkets with an offer to sell crayfish through constant deliveries from your farm. Large supermarkets in the country have fish departments that sell not only fish, but also crayfish. However, many wholesale hypermarkets (where, by the way, restaurants and cafes buy their products) do not have such goods. Therefore, it’s up to you - by calling all major sales points, you will probably find clients. And this is a sure signal that the crayfish farming business plan for this method of trading will pay off in the future.

Another way to create a customer base is to simply sell the product through 2-3 acquaintances or friends. They, in turn, will tell their friends. In other words, word of mouth will start working. But in order to ensure a constant influx of customers, you must adhere to several basic conditions: high quality goods, prices lower than in supermarkets and other sellers, and, as an option, improved service - home delivery of crayfish. Thus, in one season you can form a permanent customer base.

Choosing the type of crayfish farm

Everything has been decided with the client base, the most important part of the business plan remains - the direct organization of a cancer farm at home. Artificial breeding of crayfish is divided into two types, depending on the form of farming: crayfish breeding in ponds and factory type of breeding. The first type is considered the most profitable, since the process is labor-intensive and large-scale capital investments are required for running a business on an industrial scale.

Lake and river crayfish are bred at home. Breeding crayfish as a business in our climate is considered impractical, since most of the year temperatures prevail that are low for reproduction. The exception is the southern regions of the country. It is very difficult to raise crayfish to a marketable state - they quickly hibernate at low water temperatures below 17 degrees and their development stops indefinitely. Therefore, the most optimal and best technology for breeding crayfish for our latitudes involves the creation of artificial closed reservoirs. Therefore, we need to breed lake crayfish, because we need to get a finished product in an extremely short time.

Technology for constructing breeding ponds

The ideal option is a body of water (or preferably several bodies of water) within your land plot. Breeding crayfish at home is beneficial due to the close location of reservoirs, you can always control the entire breeding process. In addition, this will significantly secure your business - there will be no danger that someone will want to collect your entire source of income.

So, several reservoirs have been dug on your site. Their depth can be 1-3 meters (in some cases it can be 6 meters), the area of ​​one artificial pond is from 30 to 60 square meters. The bottom should be rocky and covered with sand, and the banks should be clay (so that crayfish can dig holes in them). Running water, as noted above, is not necessary for breeding crayfish. The main thing is to have a water source nearby so that you can fill the reservoirs with water and change it periodically.

Drainage pipes are also needed, which will perform the function of draining and pipes through which water will flow into the ponds. The drain should be covered with a wooden net. Metal mesh is harmful to crayfish, and they can easily bite through an ordinary fishing net. When all the drains are ready, you can start filling the reservoir with water and adding crayfish there. It is necessary to update the water once every 2-3 weeks, replacing no more than 30% of the water, so as not to disturb the established microclimate.

Home breeding of crayfish is also possible in aquariums, and this is one of the most profitable methods. Firstly, it is a much more convenient catch, secondly, it constantly maintains the optimal temperature, and thirdly, there is no need to constantly replace the water, it is enough to install cleaning filters. In addition, crayfish molt in an aquarium more often - up to 3 times a year, while in reservoirs they molt once. Molting is direct evidence of the growth of crayfish (the shell becomes tighter), which means the product will be ready for sale faster.

The only drawback of aquariums is the limited space available. It is not possible to install more aquariums than the room allows. In addition, costs for electricity and space heating increase. But at the same time the volume of production also increases. But if you already have customers who are willing to constantly buy crayfish, you don’t have to worry about profitability. The cost of the crayfish will be worth the money spent.

You have a customer base, you know what kind of crayfish to breed, where to grow them and in what conditions. The only thing left to do is decide where to buy crayfish for breeding and how to properly keep them? If you live near a river or any other body of water in which these invertebrates are found, you can catch them yourself using special fishing rods, nets (a cylindrical net) or nets. Trapping can take place from mid-summer to the end of November. In dark waters the best catch will be in the evening, in clear waters - at dusk. It is also advisable to catch crayfish in rainy weather and a warm night.

If this is a rather complicated and time-consuming process for you, there is another option. Selling crayfish for breeding is one of the ways to earn money for local residents who live near reservoirs and fish. Usually a kilogram of crayfish costs 100 rubles, so you can buy a large quantity. It is best to buy fingerlings - crayfish that appeared in this year, it is from them that you can make a good profit in the future.

• Regularly monitor the renewal of water so that it does not stagnate;
• Maintain the optimal temperature for adequate nutrition of adult crayfish - it is 17-21 degrees, for larvae - several degrees higher;
• Crayfish, like all other representatives of the animal world, can get sick. Industrial crayfish farming involves maintaining optimal conditions, and this is different in each country. But everywhere the requirements are the same: standard hydrochemical and temperature conditions;
• You can feed crayfish with larvae, insects, fish, crustaceans, and worms. But before directly catching them for sale, it is necessary to put them on a special “diet”: feed them only with nettles, potatoes and other vegetation. It is not recommended to give fresh fish, since crayfish will get into fights while eating, losing claws and legs, and, as a result, their presentation. These are the basic conditions for breeding crayfish.

Costs, quantity of initial goods and liquidity

Of great importance is the acquisition of females with live eggs on pleopods (legs under the tail) and their transportation to crayfish farms. In order to grow a ton of crayfish, it is necessary to purchase about 450-600 fertilized females, which are caught from their natural habitat. With an average female weight of about 160 grams, the result is about 80,000 grams of live weight, which is 80 kg. crayfish that need to be purchased for breeding.

Thus, we can calculate the profitability of crayfish breeding: 80 kilograms of crayfish at a purchase price of 100 rubles will cost 8,000 rubles. Let's add to this the single costs of organizing and creating artificial reservoirs - about 180,000 rubles. It turns out 188 thousand rubles of start-up capital for running such a business. Now you can calculate how much profit these funds will bring. At the same time, we take into account that you have drawn up a sales plan and the customer base is already ready.

Suppose that in one season, 500 female crayfish give rise to 13,000 live offspring (at optimal conditions). The market value of 1 kilogram of crayfish is about 200-250 rubles. Adult crayfish weigh up to 300 grams, which is total number will be about 3.5-3.9 tons of goods ready for sale. In total, provided that the crayfish are fully marketed and sold at wholesale cost, 500-700 thousand rubles of income are obtained, of which 312-512 thousand rubles are net profit for the season. As you can see, this way of doing business, such as breeding crayfish at home, is a cost-effective way to make a profit.

These conclusions were given after conducting experiments on breeding and growing crayfish by one of the domestic scientists. It is quite possible that they will be useful to you in the future:

After 1,400 fertilized females had given birth, the young crayfish were removed from the cages from the females. Instead, 600 males were placed there, and despite the fact that fertilization took place on time - in early November, this did not give any positive results. From this it was concluded that old females cannot be kept in the pool for more than 3-4 months.

It is also impossible to keep old females for the reason that during breeding it was noticed that they eat their own cubs. This means that after the females lay eggs, it is necessary to move them to another pool, and leave the eggs separately for a year - until the crayfish appear and acquire hard shells.

Crayfish are very sensitive to changes in external conditions, so immediately after being caught from their natural habitats and moved into a body of water, they can crawl out of the water. Therefore, it is advisable to keep the crayfish in a basket for several weeks and feed them there. After this, you can safely release the crayfish into the reservoir - they will no longer climb to the surface.

It is advisable to carry out transportation in containers covered on the inside with smooth straw or moss. Before releasing them into the pond, first water the crayfish with warm water from a watering can.

If you like this type of business, you can additionally watch a video about crayfish breeding and educational materials, where each stage is clearly described and explained. It is worth noting that the process of breeding and growing is quite interesting, and with due effort it can develop from an ordinary hobby into a source of permanent income.

Crayfish are invertebrate animals. They are in great demand throughout Russia. Natural populations of crayfish are decreasing every year due to poaching and disease. Natural reserves of crayfish reach their maximum every eight years, after which they decrease to a minimum.

Currently, much attention is paid to breeding crayfish in artificial reservoirs. In terms of per capita consumption, Greece and Italy lead. Crayfish were brought to these countries from the former Soviet Union. Every year, these countries supply up to 11 thousand tons of commercial crayfish to the foreign market. Spain, Portugal and China also supply crayfish.

In country and homestead ponds, you can successfully breed fast-growing species of crayfish, such as broad-toed and long-toed. Common crayfish live in rivers, lakes, ponds, floodplains, streams with clean soft water, on clay, sandy, peaty, but not rocky bottoms. The favorable water temperature for crayfish is not lower than 12 degrees Celsius. The depth of the reservoir is from 1.5 to 6 - 15 m. The best habitat for crayfish is coastline a reservoir with inflows where aquatic vegetation grows well.

When eating vegetation, calcium metabolism in the body of crayfish accelerates, which contributes to the hardening of the shell after molting. On a small dam near a river, the soil near the shore should be such that it is convenient for crayfish to build holes. In addition to burrows, crayfish can be found under stones, stumps and roots.

Typically, crayfish make burrows on steep, shady banks where there is little sun. Reeds, willows, acacias, and willows can grow on the banks. Burrows can be of the following sizes: length 10–40 cm, width 5–20 cm, height 3–18 cm. In winter, crayfish burrows are located at the very bottom of the reservoir, in summer - closer to the shore, depending on the temperature.

Crayfish dig burrows using their legs and tail, supported by their front claws. Crayfish need tails not only for digging holes, but also for swimming. They swim backwards and at the same time hit the water with their tail. Crayfish, as a rule, do not live in acidic water. The optimal amount of oxygen dissolved in water for crayfish is 7–8 mg/l. A short-term reduction to a level of 2–4 mg/l is possible.

Typically, crayfish are nocturnal, but if they smell prey, they will strive for it during the day. They feed on shells, slugs, insect larvae, worms, carrion that is not very rotten, young stems of reeds, water lilies and other plants. Crayfish especially readily eat algae rich in lime, which, like the peel of shells and slugs, is used to form a shell. The shell consists of chitin - 46.73%, calcium carbonate - 46.25%, calcium phosphate 7.02%.

Female crayfish always sit alone in burrows, while males often gather in groups during wintering. Crayfish are dioecious animals. Males of long-clawed crayfish reach sexual maturity in the third year with a body length of at least 7–9 cm, and females in the fourth year with a body length of 6–7 cm. Some males are 2–3 times larger than females. The surest signs of difference are the genitals lying on the thoracic side, at the border of the chest and tail. In the male, the paired openings of the gonads are located at the base of the last pair of legs, in the female they are located at the third pair from the end. Already in September, in the female’s ovary, from 100 to 300 yellowish testicles are formed; at the same time, the male’s sperm ducts begin to greatly increase, looking like two thick white intertwined threads.

Mating occurs in October–November or February–March. In terms of timing, a lot depends on the region. Mating duration is from 15 to 20 days. Fertilization occurs inside the body. A male can fertilize up to four females in a row. After mating, the female retires to her burrow and 20–25 days after mating begins spawning, releasing eggs through the genital openings. The number of eggs in the broad-fingered species of female crayfish, from 7 to 8 cm long, reaches 68 pieces, and in the long-fingered crayfish - 60 pieces. In the broad-fingered species of female crayfish, from 8 to 9 cm long, the number of eggs reaches 93 pieces, in the long-fingered crayfish - 102; in the broad-fingered species of female crayfish from 9 to 10 cm long - 163 pieces, in the long-fingered species - 174. In the broad-fingered species of female crayfish from 11 to 12 cm in length - 302 pieces, in the long-fingered species - 350 pieces. In the broad-fingered species, female crayfish from 13 to 14 cm long have 425 pieces, in the long-fingered species there are 500 pieces.

The eggs quickly stick under the abdomen to the spoonpods and remain there until the larvae hatch. Since the eggs must be continuously washed with water enriched with oxygen, the female drives the water with a splash, bending and unbending the end of her tail. Calm water, if the female sits in a hole, stagnates, becomes depleted of oxygen and the eggs die.

Crayfish eggs can be easily damaged by water scorpions, swimming beetles, and smooth beetles. The female constantly washes the eggs from dirt, mold and algae. A female crayfish can have from 120 to 500 eggs. The hatching time of crayfish offspring depends on the weather and region. As a rule, hatching occurs at the beginning or in the second half of summer.

Externally, crayfish larvae differ little from adults, except for size. The length of one-day larvae reaches 9–16 mm. At first, they remain attached under the female’s abdomen and hold onto the mother’s leg-shaped appendages with their claws. After 10–12 days they begin to swim near the female, but in case of any danger they hide under the abdomen. After 45 days, the larvae leave the female forever. In the first summer they change their shell 7–8 times, in the second summer - 5 times, in the third and subsequent years the male 2 times, the female 1 time. This exchange occurs in a period of time from 10 minutes to several hours.

They grow slowly. By autumn they reach 3–3.5 cm in length. By the end of the second year of life, young crayfish grow to 7–9 cm, at the age of three years – 10–12 cm; By the age of five, the cancer can reach 12–15 cm in length; by the age of 20, large specimens reach 20–25 cm in length. At the age of 8–10 years, crayfish reach a length of 10–11 cm or more.

Juveniles raised in rivers and lakes reach commercial size in the third or fourth summer. In ponds, two-year-old crayfish during the warm season reach a fishing length of 10 cm and a weight of 32 g. Some crayfish with a size of 12.3 cm reach 70.5 g of weight or more. The survival rate of fingerlings in ponds with a good food supply during the growing season is much higher (85–90%) than in natural reservoirs (10–15%). The high growth rate and survival rate of juveniles is explained by the good food and temperature conditions that they find in artificial reservoirs. In rivers, juveniles do not receive even the minimum diet that covers energy expenditures for searching for food and metabolism in the body.

Under natural conditions, the sexual maturity of crayfish occurs in the third year of life with a minimum size of females of 6–7 cm. A 10-centimeter crayfish of four years old can be considered already a breeder. The timing of mating depends on the conditions in the reservoir and water temperature. In some regions this occurs in March - April at a water temperature of 8 - 12 degrees Celsius. Larvae hatch from eggs in the second half of May - the first half of June at a water temperature of 21–24 degrees. The larvae begin to live independently in such conditions 10–14 days after hatching.

Under natural conditions, crayfish pass next stages development. First stage: development duration is from 1 to 7 days, larval size is 1.5–2 mm; second stage: duration of development from 5 to 8 days, larval size 8.7 mm, weight 14.7 mg; third stage: development duration from 9 to 14 days, larval size 1.2 cm, weight 34.7 mg; fingerlings: development duration up to 90 days, larval size 3 cm, weight from 8 to 19 g; two-year-olds: larval size 6 cm, weight 32 g; sexually mature: development duration is three years, larval size is 6.7 cm; sexually mature: development duration 10 years, larval size 9 – 10 cm, weight – 50 g.

Depending on the age, crayfish have the following dependence in size: at the age of 20 days, the length of the male reaches 21.9 mm, the length of the female – 21.6 mm; at the age of 30 days, the length of the male is 28.5 mm, the female is 28.0 mm; at the age of 40 days, the length of the male is 34.7 mm, the female is 33.87 mm; at the age of 50 days, the length of the male is 40.2 mm, the female is 39.3 mm; at the age of 60 days, the length of the male reaches 45.3 mm, the female – 44.2 mm; at the age of 70 days, the length of the male is 49.9 mm, the female is 48.6 mm; at the age of 80 days, the length of the male is 54.0 mm, the female is 52.5 mm; at the age of 90 days, the length of the male is 57.7 mm, the female is 56.0 mm; at the age of 100 days, the length of the male is 60.7 mm, female – 59.0 mm; at the age of 110 days, the length of the male is 63.3 mm, the female is 61.5 mm; at the age of 120 days, the length of the male reaches 65.4 mm, females 63.4 mm.

Some methods of breeding crayfish

Since the testicles come out already fertilized, the main care must be focused on the female carrying the testicles, placing her in a safe room where she can be fed until the young crayfish fall away from her. Small crayfish should be fed until autumn in pools or small flowing ponds with steep banks and a dense bottom, into which water is carried through pipes with a diameter of 20–25 cm.

There are various practices for raising crayfish. In some farms, crayfish are grown in wooden waterproof boxes made from 5-centimeter boards. The length of the box is 12–15 m, width 6 m, depth 1.2 m. The manufactured boxes are placed on the bottom of a dry pond. Water is carried into the pond through pipes with taps and outlet pipes. Small cells with a volume of 5 cubic meters and several floors are arranged along the walls of this pool. The cells are placed one above the other so that the walls of the pool form them back wall, and the cell should be open in front so that the crayfish can freely enter and exit it. Each cancer has its own cell.

Then stones and stumps are piled on the bottom of the pond so that the crayfish can hide under them. In two corners of the pond, small mounds of rich, marl clay are poured with a layer of 90 cm in height and planted with reeds, watercress and other plants. After installation, the pool is filled with water and more than a thousand females with fertilized eggs are placed in it. The crayfish are fed with waste of finely chopped meat, young frogs, fish meat, etc. The water flows with a constant current in a stream 25 cm thick and leaves through an outlet pipe protected by a mesh with small cells. In mid-October there may already be more than 20 thousand crayfish. Young crayfish are left until they grow a strong shell.

Under natural conditions, it is rare to find a female with more than 20 crustaceans on her tail, and some of these twenty themselves fall off prematurely, others die, so on average each female raises no more than 12 crustaceans per year. When breeding in reservoirs - pools, you can get from 35 to 65 crayfish from each female.

To remove juveniles from females, you can use the following method. Shortly before the crayfish hatch from the eggs, the females are placed in a large pond, divided into two floors by nets. The upper mesh has quite large cells; after falling away from the mother, the crustaceans will fall through them to the lower floor, where there is a second mesh with very small cells. On it, crustaceans receive the necessary food and protection from enemies.

Crayfish are very picky about water, and it often happens that they begin to crawl out of the water immediately after they are placed in a pond, lake or other body of water that looks quite suitable for their breeding. In such cases, you should keep them for several days or weeks in a basket, circle, top, lowered into water, and feed them there. If after this they are released into the wild, they immediately begin to look for places in the water where they can hide and no longer try not to get out of the water. In ponds with clean water, abundant vegetation and low water flow artificial feeding rapid cultivation of crayfish can be achieved.

In order to increase crayfish stocks and the cancer productivity of reservoirs in ponds and other natural reservoirs, it is necessary to conduct proper management, which involves carrying out biotechnical measures in rivers and reservoirs and artificial breeding of crayfish in ponds. In pond crayfish farming, crayfish productivity is understood as the increase in crayfish per unit area during the growing season.

To determine the value of the crayfish productivity of ponds, it is necessary to subtract their planting weight from the weight of the grown and caught number of crayfish (per unit area). The annual increase obtained in a pond per unit area due to natural food is called natural cancer productivity, and the increase due to natural food and feed introduced into the pond for feeding crayfish is called total cancer productivity. In natural reservoirs, crayfish productivity refers to production, that is, the catch of crayfish per year per unit area.

The catch of crayfish obtained from natural food found in water bodies depends on the availability of food and the degree of its use. The formation and development of food in water bodies depends on environmental conditions that contribute to the intensity life processes. As a result of complex biological processes At the bottom of the reservoir, the organic matter of sludge is destroyed by microorganisms, the oxidized elements of the ash part of the sludge are released, the water is enriched with mineral salts and the creation of primary products - phytoplankton and bacteria that absorb a solution of mineral salts and organic compounds from the water. Subsequently, the development of zooplankton and benthos occurs, feeding on primary products (phytoplankton and bacteria), necessary for the development and growth of crayfish.

Thus, cancer production is created as a result of the biological cycle of substances, and the amount of natural cancer production depends on the intensity of life processes that determine this cycle.

Food supply of reservoirs

Lower unicellular algae and bacteria that develop in the water column are united under the general name - plant plankton (phytoplankton). Algae reproduce by division very quickly. After three days, their number increases fivefold. Algae are used as food by lower aquatic animals - zooplankton, which inhabit the water column, most of which die and fall to the bottom.

Dead algae are partially used by organisms inhabiting the bottom of the reservoir (benthos), and most of it accumulates in the form of organic residues. Bacteria that develop in water reproduce even faster than algae. In 15 hours, one bacterium can produce 1 billion offspring. Some of the living bacteria, together with living algae, are consumed by zooplankton. A significant number of them die, decompose, mineralize and re-enter the biological cycle.

If there is enough oxygen in the water, organic matter decomposes quite quickly as a result of bacterial activity. In this case, carbon and hydrogen turn into carbon dioxide and water, nitrogen from protein compounds turns into urea and ammonia. Then, under the influence of nitrifying bacteria, nitrate nitrogen is created, which is well absorbed by green algae. The development of life processes in ponds creates good conditions for protein synthesis in the body of crayfish.

In addition to carbon, hydrogen, oxygen and nitrogen, the protein substances of crayfish include phosphorus, sulfur and iron (blood hemoglobin). The bones of crayfish are rich in calcium. Calculations and chemical analyzes of water show that the annual growth of crayfish contains significantly more nitrogen and phosphorus than the water of ponds, which is explained by the biological cycle of substances occurring as a result of the development of life processes in ponds. Biological cycle arises as a result of various durations the life of organisms and the ability to reproduce.

The fast and intense life process in ponds contributes to the intensive development of organisms used by crayfish as food. However, the amount of certain salts in water does not yet determine the intensity of life processes and the amount of cancer productivity. The amount of certain mineral salts present in the soil is no less important. Water leaches mineral salts from the soil, dissolving them, thereby preparing food for lower algae. Organic matter in the soil is used by bacteria and ciliates for nutrition.

Ponds built on chernozem soils have the highest cancer productivity. Ponds with loamy, clayey and sandy soils are less productive. Mineral salts and organic matter in the soil are of great importance only in the first years after the formation of a reservoir. Then, as it ages, this value is lost. In old ponds, the role of the soil in replenishing nutrients is played by pond silt, which accumulates at the bottom. Organic substances of pond sludge containing protein, under the influence of microorganisms, enter into the cycle and provide food for phytoplankton. The cancer productivity of the pond depends on the intensity of the work of bacteria supplying nitrogen and phosphorus to the water. Nitrogen promotes the growth of plants and animals, and phosphorus promotes the growth and acceleration of decomposition processes in plant organisms, as well as the development of reproductive products in animal organisms.

Nitrogen compounds are deposited in pond mud and serve as fertilizer for underwater and above-water plants. Some of the nitrogen contained in living organisms consumed by crayfish also falls out of the cycle. The amount of nitrogen in the ponds is replenished annually. It comes with water runoff from drainage areas in the form of mineral salts and undecomposed organic residues. An indirect indicator of quantity organic matter in water is its oxidability. The degree of oxidation is determined by the amount of oxygen absorbed by one liter of water to oxidize the organic substances contained in it. If oxidation is low, this indicates that the water is poor in nutrients for the development of phytoplankton.

For pond farms, water is considered good if its oxidability does not exceed 20 mg 02/l. If the oxidation of water is more than 20 mg 02/l, this indicates contamination of the water supply source. Such water is unsuitable for breeding crayfish.

Phosphorus, determined in combination with oxygen, is the most important biogenic substance. It is consumed by plant organisms along with nitrogen and is part of plant protein, digestible by animal organisms. Phosphorus is contained in water in the form of phosphoric acid salts and organic compounds. The main source of phosphorus replenishment in ponds is water runoff from fertilized fields in the catchment area. Phosphorus absorbed by crayfish is carried away from the reservoir and excluded from the cycle. Ordinary, unpolluted sources contain up to 0.5 mg/l of phosphorus. For intensive development of green algae, 0.2 mg of phosphorus/l is sufficient.

High productivity of crayfish breeding can be achieved provided that the nutrients in the pond are used by beneficial consumers. Of the lower algae that are part of the phytoplanton, beneficial consumers include microscopic protococcal green algae, mainly chlorella and scenedesmus. Blue-green algae consume nutrient salts and play a negative role. They are not used as food by zooplankton and are almost never eaten by crayfish.

Secondary production in the reservoir consists of zooplankton and benthos. Zooplankton includes ciliates, rotifers, copepods and cladocerans. Ciliates develop mainly in the coastal zone of ponds and serve as food for crayfish only in the first days after the larvae hatch from the eggs.

Copepods found in ponds are very valuable for crayfish breeding. They reproduce in large numbers at all times of the year, especially in early spring, when crayfish, exhausted after winter, begin to feed. Cladocerans are also fertile. This group includes daphnia, bosmina, polyuphemus, etc. The most valuable among the cladocerans are daphnia and moinae, which are specially bred as food for crayfish and fish.

In feeding ponds, the crayfish feeds only on part of the zooplankton - the larvae of the pusher mosquito and other mosquitoes. Mosquito larvae, chironomids or tendipedids, known as bloodworms, are of primary importance for feeding crayfish. Mollusks and their various forms contained in benthos are of some importance in the nutrition of crayfish.

Harmful insects to crayfish in a pond include water beetles, bedbugs and dragonflies. The beetles even attack crayfish fry. Particular harm to juvenile crayfish is caused by such beetles as reindeer, pond snail, water lover, diving beetle, silt beetle and their larvae. Adult dragonflies and their larvae consume crayfish food. Frogs and tadpoles also consume crayfish food. Tadpoles also eat cake, the food given to crayfish.

How to breed crayfish in ponds

Crayfish are bred in ponds of complex importance; drained bays of reservoirs specially built for crayfish breeding; massifs of peat workings; quarries; small reservoirs; sections of small rivers; estuaries; ilmenyah; lakes; rice fields, etc.

Based on the nature of water supply, ponds are divided into key, stream, river, channel, floodplain, etc.

Key ponds are supplied with water from permanent springs. They are usually constructed by embanking part of the valley or beams adjacent to the terrace above the floodplain, from which springs flow. Most ponds have a uniform depth throughout the area. At the dam they are made a little deeper - 1–1.5 m. As a rule, the water in the spring ponds is cold, with the exception of large ones with an insignificant flow of spring water. The size of ponds usually does not exceed 5 hectares, but larger ones are also found. Chemical composition pond water fluctuates greatly and mainly depends on the quantity and quality of water in the spring and on the soil on which the pond is located. In most cases, key ponds are flowing.

Stream ponds are replenished with water from streams that have a constant flow of water from springs. Ponds are created by blocking the valley with a transverse dam. These ponds have a deep part near the dam with a gradual decrease in depth towards the tops of the ponds. Such ponds usually have a well-developed coastal zone. The water temperature depends on the distance the water travels before it enters the pond, the size of the pond and the flow rate of the stream. At the sources the water is cold, further from the source and in the absence of coastal springs it is warmer than at the source, no colder than in ordinary lowland rivers. The area of ​​these ponds is small - from 5 to 10 hectares, but can be 25–30 hectares.

River ponds are supplied with water from rivers. According to the nature of their structure, they are divided into channel and floodplain. Channel dams are created by blocking the river valley with a transverse dam. The main purpose of the dam is to use water energy for small hydroelectric power stations, driving mills, grist mills, butter churns, to supply water to crab nurseries located in the floodplains of the river below the dam, etc. The area of ​​such ponds can be from 5 to 350 hectares. The depth of the reservoir is usually at least 3–4 m. Towards the top and along the banks, the depths go to zero.

Ponds are generally warm-water and durable. The salt composition of the water in them depends on its quality in the river, the drainage area and its drainage, on the nature of the bottom bed and on ground inflows. Floodplain ponds are formed when the lower part of the floodplain is embanked. Water is supplied to the ponds to the level of the pond's water horizon using a dam that raises water in the river and canal, which is located in the elevated part of the floodplain. Such ponds are located in the floodplain of the main river and are supplied with water from a channel.

Floodplain ponds are arranged for breeding crayfish, as well as for gravity irrigation of land plots located on the floodplain below the pond. Ponds vary in size; in crayfish farms they are made with an area of ​​30–100 hectares. At the dam, the depth of the ponds does not exceed 1.5–2.0 m and gradually decreases towards the terrace above the floodplain. The chemical composition of pond water is determined by the quality of the river water and the soil of the pond bed. Summer rainwater and ground currents have almost no effect on water quality.

Atmospheric ponds are fed by surface runoff. As a rule, they are filled with groundwater and rainwater (ground-atmospheric nutrition). Ponds are constructed by blocking wet hollows and gullies that have inflows of surface groundwater. At the dam the depth of the ponds is 1.5–2 m, then it gradually decreases towards the top. The area of ​​soil-atmospheric ponds can be from 10 to 50 hectares. The composition of water is determined by the quality of spring water flowing from the catchment area, the soil of the bed and groundwater. IN winter time Deaths are observed in such ponds.

Ponds with atmospheric water supply are built in the same way as soil-atmospheric ones, only they are laid in dry valleys and ravines that do not have an inflow of surface groundwater. They are supplied with water from spring and summer runoff. The area of ​​the ponds is 10–50 or more. Such ponds are inhabited by crushed crucian carp.

Floodplain dams are among the reservoirs with ground-atmospheric water supply. They are erected by embanking a section of the floodplain or by means of a transverse dam in the lower part of the floodplain, flooded by flood water. From the beginning of the decline in low water, shields are installed in the dams to block the water.

Dams are located in logs above the water horizon in the river. Every year they are filled with flood waters. They are replenished with water from summer runoff from the local catchment area and partly from groundwater. Dams are mainly used for breeding crayfish and for irrigation. The area of ​​such ponds is from 5 to 100 hectares. Their banks are flat and overgrown with vegetation. Steep and steep banks are rare.

When constructing new ponds and devices for breeding crayfish, the following should be provided: a drainage system that allows water to be drained and drained the pond bed for the winter or only in the fall for the time of catching crayfish, as well as a crayfish-barrier top that prevents crayfish from leaving the ponds if they are built on small rivers and streams.

If for some reason the water from the pond cannot be drained, two or three ponds should be built, placing them one after the other. With this arrangement of ponds, water is first drained to catch crayfish from the lower pond, then it is filled with water from the pond located above. The upper pond is left drained for the winter, and the remaining water reserves in the lower pond are used for various needs.

How to make drainage ditches. A proper pond ditch network includes a main ditch, side branches to low-lying areas, and upland ditches that intercept groundwater and prevent waterlogging of individual areas of the pond. It is necessary to arrange drainage ditches in such a way as to ensure complete drainage of water from low areas, as well as to drain the pond bed.

In terms of their design, ponds must comply with sanitary and hygienic requirements aimed at creating unfavorable conditions for the development of malaria mosquito larvae. To avoid swamping of areas adjacent to pond dams, quarries are made drainage or a ditch is provided for discharging seepage water and draining the adjacent area. The river bed located below the dam is straightened to lower the water level in the river and drain the floodplain. Small ponds and large ponds with shallow floodplains should be avoided.

When constructing complex ponds, special attention should be paid to their depth. For breeding crayfish in the northern regions and middle lane average depth ponds should be within 0.8 m, in southern ones - 1 m. For feeding ponds, such ponds are optimal. At greater depths, crayfish production decreases. When constructing floodplain ponds in specialized farms, smaller average depths are allowed. In some cases, at such depths, the productivity of crayfish becomes greater.

The choice of sites for constructing ponds is of great importance for crayfish production. Ponds can be built on a variety of plots of land with different soils, provided that dams can be built on them and the areas filled with water. The more fertile the soil of the pond, the higher the productivity of crayfish in it.

Quite often, low-fertility soils that are unsuitable for arable land are allocated for ponds - saline, dry areas in ravines that produce low yields of grass, etc.

How to breed crayfish in the bays of reservoirs

Navigable and energy reservoirs differ from ordinary reservoirs by strong fluctuations in water levels, especially in the summer, when the flow of water into the reservoir is reduced to a minimum. In various reservoirs, such fluctuations reach 2 -17 m. As a result of a decrease in the water level in the reservoir, a temporary drying zone is formed. This feature is sharply expressed in reservoirs of the plains with their vast areas of shallow water, constituting from 40 to 80% of the reservoir area.

Typically, shallow waters are drained in the autumn-winter period. During the spring flood, the drained areas are again covered with water. In seasonal reservoirs they are completely covered, in reservoirs of long-term regulation - completely in high-water years.

In contrast to the temporary drainage zone, the non-dischargeable part of reservoirs is called a permanent flood zone. For the life of crayfish in reservoirs, the zones have different meaning. The zone of constant flooding is the wintering site, and the drying zone is usually the breeding site. Both zones can be successfully used for breeding crayfish.

Draining large areas of shallow water and at the same time complete liberation removing them from wild crayfish during this period opens up great prospects for organizing pond crayfish farming. Water level fluctuations occur here in the same way as in conventional reservoirs. The decrease in the water horizon begins in the summer and continues until the spring flood.

The drained areas of reservoirs suitable for constructing ponds are the floodplains of small rivers, streams, gullies, hollows and other depressions along which water flows from the drainage area into the rivers. In autumn these areas are drained and frozen in winter. During the spring flood, dried and frozen areas are again covered with water.

With the least amount of money, bays that cut deeply into the mainland and have a narrow exit into the reservoir can be used. The hydrological regime of fenced-off bays differs from ponds in that the bays are filled with water not directly from the drainage area, but from the reservoir, with the beginning of the water rise.

The water temperature in the ponds at this time is significantly higher than in fenced off bays, since colder water from ice-covered reservoirs enters the bays. Subsequently, the water temperature in the bays is almost the same as the temperature of the ponds.

Fenced-off bays are divided into two groups according to water supply conditions. One group includes bays with dependent water supply, the other - with independent ones. Bays with dependent water supply receive water from reservoirs and when the water horizon drops, the reservoir is not replenished with water. Bays with an independent water supply can receive water from the reservoir in the spring, and after the water horizon drops, the water in the reservoir is supplied with water due to the constant influx of water in streams and rivers flowing into the bay. The salt composition can be different, since, in addition to soils, wastewater also affects the quality of water in bays.

According to the conditions for releasing water, bays are also divided into two groups - early and late release from water. The early release bays can be drained in the fall before freeze-up, the late release bays - only as a result of the winter lowering of the water horizon during the freeze-up period.

Bays, deeply cut into the mainland and freed from water at the end of September, are usually used for feeding ponds. This makes it possible to fence off large areas from the reservoir with dams in the autumn. To reduce the cost of crayfish production and maintenance, individual bays are made at least 15 hectares in size. The greatest depth of the bays should be close to the depths of the crayfish ponds - 1.5–2 m.

To completely drain the bays, it is necessary that the greatest depths be in the lower part of the bays, and gradually decrease towards the middle and upper parts of the bay. If there are streams flowing into bays, the depths of the ponds during the period of depression in the channel part should not exceed the height of the reservoir level.

How to breed crayfish in peat excavations

Peat massifs are divided into high, transitional and lowland. In the northern regions, highland peat bogs predominate; to the south, lowland peat bogs are more common. Raised peat bogs are formed as a result of the deposition of dying sphagnum mosses, wild rosemary, cotton grass, pommel, cassandra and other plants that tolerate high acidity, under which decomposition occurs slowly.

In lowlands, hollows, floodplains of rivers and on lakes, lowland swamps are formed as a result of the deposition of dying remains of reeds, sedges, cattails, reeds and other plants growing in an alkaline, slightly alkaline or neutral environment. In such swamps, the process of decomposition of vegetation remains is inhibited not by increased acidity, but by a lack of oxygen. The water of lowland swamps contains little dissolved oxygen. Atmospheric oxygen is prevented from reaching decaying vegetation due to the layer of water covering the swamps. Transitional swamps occupy a middle position between highland and lowland swamps.

Exist different ways peat extraction, after which excavations of varying quality remain. With the hydraulic method, quarries look like long and wide reservoirs. If the machine-molding method is used with baggers or excavators, narrow and long quarries with a depth of 3 m or more are obtained. With the milling method, when peat is produced in thin layers, milling fields remain of a relatively large area, with a flat bottom. Such fields are most suitable for constructing ponds. The natural productivity of ponds on them is almost twice as high as ponds built on quarries that are mined hydraulically.

In peat workings, the soil is generally acidic, with a pH of 4.1–4.4, which means that the natural productivity of crayfish ponds there is very low unless liming is carried out.

The soil of peat excavations contains many organic compounds tightly bound to colloids of humic substances, which quickly adsorb phosphorus compounds found in the form of insoluble compounds. To use these organic compounds, it is necessary to eliminate the acidity of the water and provide a sufficient amount of oxygen in the bottom layers for the development of microorganisms that mineralize organic matter and enrich the water with nitrogen and phosphorus.

Ponds on peat workings are almost no different from ordinary ponds on peaty or loamy soils, except for the pH of the water, which ranges from 6.6–6.8. If you add lime to the soil every year, the pH of the water will approach neutral. In ponds in peat workings, the food supply develops well, especially zooplankton, the intensive use of which ensures high productivity of crayfish.

How to breed crayfish in reservoirs

Based on the nature of water supply, reservoirs are divided into several groups: with water supply from precipitation, from permanent sources and with mixed water supply.

Irrigation reservoirs are constructed to retain atmospheric water. In spring they are filled with water to the design level. In June, water is taken from the reservoir for irrigation, as a result of which its horizon decreases and the area is reduced by almost 70% of the area flooded in spring.

In such reservoirs, the density of crayfish planting is calculated based on the average density, which is half the sum of the area of ​​the reservoir when crayfish are planted and its area in August, after water flow, or according to the maximum surface of the spring flood. When calculating based on the maximum surface of spring flooding with a decrease in the area of ​​the reservoir in summer, crayfish need additional feeding.

For some industries, for example, starch, sugar factories, some metallurgical and others, industrial reservoirs are installed. These reservoirs can be quite successfully used for growing crayfish, provided that the water is released and the crayfish are caught in winter or early spring and then refilled with water during high water. For breeding crayfish, such reservoirs are best used using pond crayfish farming methods by annually populating and catching everything that is grown, for example, reservoirs that can be lowered or fished longitudinally, as well as by methods of reproducing herds that do not have conditions for reproduction and do not go with the water into time of spring flood.

To catch crayfish, when constructing new reservoirs, provision should be made for bottom drains to completely drain the water. Large reservoirs, the water from which is never drained, must be adapted for seine fishing by smoothing out the unevenness of the bottom. To do this, remove bushes, trees and thickets of tough vegetation and uproot stumps. After removing stumps and stones, the holes are covered with earth; The steep banks of ravines and rivers are cut at an angle of 45 degrees. If reservoirs are populated with crayfish, provision should be made for the construction of dismountable crayfish-barrier dams during floods.

How to breed crayfish in shallow lakes

The country has great amount Small lakes are quite suitable for successfully breeding crayfish, but they are almost never used for these purposes.

Floodplain lakes of various sizes are part of the hydrological complex of rivers, in the floodplains of which they are located and are divided into several types: oxbow lakes, riverbed lakes, central floodplain (valley), near-terrace floodplain and dam lakes.

Typically, floodplain lakes are shallow, with an average depth of 1–1.5 m; in summer, the water in them warms up well. The content of dissolved oxygen in water fluctuates sharply throughout the day. During the day, the water is oversaturated with oxygen; at night, the amount of oxygen decreases due to the intensive consumption of oxygen by algae and the decomposition of organic matter at the bottom.

In winter, when the lakes are covered with ice and snow, the oxygen in the water is gradually depleted by the decomposition of algae, which die off in the fall. Oxygen deficiency is accompanied by complete death. Therefore, crayfish breeding in floodplain lakes is carried out by spring planting and mandatory autumn catching of grown crayfish.

Floodplain lakes have an excellent food supply. Despite prolonged coverage by a significant layer of water during floods, zooplankton maintains a constant species composition. Particularly strong development of phytoplankton and zooplankton is observed after the decline of high waters. The benthos is distinguished by its diverse species composition and abundant development, especially of larvae and chironomids. In large quantities in the lakes there are larvae of various insects, oligochaete worms and various mollusks. The residual mass of the bottom natural food of crayfish reaches 100 g per 1 square meter. m. In terms of natural productivity of crayfish, floodplain lakes are often superior to ponds.

As crayfish grounds, floodplain lakes are divided into several groups - drainage, non-discharge oblong oxbow lakes and wide lakes of the central floodplain. The bottom of the drainage lakes is located above the water horizon in the river, so they are easy to make drainage. Such lakes are no different from drainage ponds; the productivity of crayfish in them can be very high.

Non-draining oxbow lakes are oblong and have a small area; they can be easily processed with longitudinal nets. Among the oxbow lakes there are also very large ones, from which crayfish are caught by pumping out water with powerful pumps. Non-draining lakes of the central floodplain usually have a large area and width and cannot be fished with longitudinal shallows either before settlement or in the fall. Crayfish can only be caught from them by pumping out water annually. The costs of pumping water do not exceed the costs of catching crayfish with seines. Leaving the bottom of lakes without water during the winter helps to increase their crayfish productivity.

Floodplain lakes, which are filled only in years of maximum floods, often become shallow and are not used for crayfish breeding. To drain such lakes, they dig a ditch or deepen the source enough to drain the remaining water and leave it for summer in years of minimal floods. Some lakes are shallow due to the great depth of the channels through which water flows during floods. The water level in them increases different ways. For example, a simple sluice is built on a discharge ditch. The lock consists of sheet piling rows at the level of the lowest water horizon and piles, which have a lateral connection with the banks by enclosing the sides with slabs, planks or blocks. The space between the side walls of the gateway is filled with soil or peat and compacted. The gateway is covered with shields inserted into the grooves of the piles in two rows. The lock is opened for the winter. When the level of spring water rises, it freely passes through the sluice and fills the reservoir.

To prevent wild animals from entering the reservoir, gratings with vertical rods are inserted into the grooves. When the water level begins to drop, the grates are removed and the sluice is closed with two rows of panels. To reduce water loss, soil or peat is poured between the panels, leaving them until autumn. During the autumn descent, shallow waters overgrown with hard vegetation are cleared of water, which improves conditions for catching crayfish.

How to breed crayfish in ilmen and estuaries

Ilmeni (depressions) are located in the southwestern part of the Caspian basin, between sandy and silty ridges. Ilmeni have an elongated shape, their bottom is muddy, the banks are sandy and flat, the depth is 1–2 m, the area is from 30 to 100 hectares. Almost all ilmens are connected by channels through which flood water flows. The total area of ​​the Ilmen fund is about 173 thousand hectares. Ilmen, which in ancient times had some importance for the reproduction of cancer stocks, has now lost its former importance.

In the area where the ilmens are located, adjacent to the western part of the Volga delta, summer is usually hot, long, with an abundance of sunny days. There is little precipitation. The amount of oxygen dissolved in water in summer ranges from 6.2 to 16 ml per 1 liter. In deep-sea ilmen, the oxygen content in winter ranges from 50 to 92% saturation. The growing season lasts almost eight months; the bottom of reservoirs is rich in food for crayfish.

In the Volga delta, winter lasts only three months with short frosts. In such conditions, for breeding crayfish, it is possible to completely dispense with the construction of wintering ponds, which are the most expensive part of a crayfish nursery.

According to specialists’ calculations, when pumping out the remaining water in the fall to catch crayfish, it is possible to create a pond farm on an area of ​​60 thousand hectares with an annual capacity of up to 300 thousand crayfish. Ilmeni, which are not subject to winter death, are also suitable for growing crayfish. It is recommended to populate them with yearlings and catch marketable crayfish not in the same year in the fall, but a year later, when the three-year-old carp reaches a weight of 2 kg. When growing for three years, you can pump out water and catch crayfish not from all the ilmen, but from half of them, which will reduce labor costs by half and ensure the production of large, highly valuable crayfish.

With a three-year cultivation period, the need for cancer-planting material is half as much as with a two-year period. With proper drainage of ilmen and draining them using pumping units, you can get more than 3 quintals, and in 2 years - 6 quintals from 1 hectare. This is exactly the productivity of crayfish in the Volga delta that was obtained in the ilmen with an area of ​​75 hectares in the Astrakhan region.

As a rule, ilmens are distinguished by a rich food supply. The benthos biomass here on average per year is 477 kg per 1 ha, compared to 103 kg in the ilmen of the central delta. The biomass of plankton is correspondingly 8 g instead of 5.2–6.5 per 1 cubic m of water. In summer, the biomass of ilmen is on average about three thousand organisms weighing 48 g per 1 square meter. m.

The drainage ilmens available in the Volga delta can be used for the joint cultivation of fingerlings and table crayfish with the release of fingerlings into the river for the reproduction of crayfish stocks. When two-year-olds and underyearlings are raised together, the cancer productivity of ilmen can be increased by 45–55%.

The estuaries that exist at the mouths of rivers flowing into the Azov and Black Seas arose in connection with the formation of deltas as a result of centuries-old river sediments and the action of sea waves, forming spits and bays. Numerous Kuban estuaries arose on the site of a sea bay, separated from the sea by a spit, which was gradually filled with sediment from the Kuban River.

The area of ​​the estuaries is constantly changing. The reasons for the changes are flat banks, shallow depths, fluctuations in the water horizon depending on its influx, etc. The shallowness of the estuaries determines their unique thermal regime, characterized by rapid heating of water in the spring and rapid cooling in the fall. In spring, the water temperature in the estuary is warmer than in the sea, and in autumn it is colder. In calm, hot weather, the water temperature reaches more than 35 degrees Celsius. In the thickets during the day, the water temperature at the bottom is 7–9 degrees lower than at the surface.

In winter, for an average of 75–80 days, the estuaries are covered with ice 15–30 cm thick. In severe winters with prolonged ice cover and large ice thickness, death occurs.

Many estuaries are silted, the silt layer usually reaches 0.5 m, in some 2–3 m. The salinity of the water is variable and depends on the connection with the river and the sea. Most of the Kuban estuaries are desalinated, their salinity is no more than 2%, while the salinity Sea of ​​Azov reaches almost 12%.

Most estuaries are heavily overgrown with coastal reeds, cattails, sedges, etc. The common underwater vegetation is chara, hornwort, pondweed, and urut. The spring cycle of zooplankton development begins in April. The biomass of zooplankton reaches 18 g per 1 cubic meter. m of water. In estuaries where salinity reaches less than 5%, crustaceans, chironomid larvae, and various mollusks develop well. Zooplankton and zoobenthos are richer in saline estuaries.

Currently, according to the scheme of crayfish reclamation measures for the reproduction of commercial crayfish in the reservoirs of the Krasnodar Territory, the main area of ​​estuaries is allocated for the construction of nurseries. 16 thousand hectares of estuaries and all dead-end estuaries that are not important for the reproduction of commercial crayfish in the Sea of ​​Azov are allocated for the construction of commercial farms.

How to breed crayfish in small rivers

A good base for growing crayfish are sections of small rivers, the length of which is more than 1 km. Small rivers are divided into mountain and lowland. The flow of rivers makes it possible to feed crayfish in them during compacted plantings and thereby increase the productivity of crayfish to 18 c per 1 ha.

The area of ​​rivers can be significantly increased by installing simple bridges on them, allowing them to raise the water horizon and at the same time use them as headwaters to retain crayfish in a fenced off section of the river. Before planting the crayfish, areas fenced off with jumpers must be carefully fished with nonsense.

How to transport crayfish

It is best to transport crayfish in baskets filled with dry, smooth straw or dry moss. When receiving crayfish at their destination, you should not immediately transfer them to water; you must first water them from a watering can while they are still in the basket.