home Audience 5 Where to start breeding crayfish. Breeding crayfish: profitable or not? How long does it take from start to finished product?

Where to start breeding crayfish. Breeding crayfish: profitable or not? How long does it take from start to finished product?

For 2018, the wholesale cost of live crayfish on the free market ranges from $ 8-10 per kilogram, especially large individuals rare species can be valued up to $20 per kilogram. The retail price (piece sale) is usually 20% higher, but this method of marketing products is only suitable for mini-farms, as well as species of arthropods with light shells. A pond with an area of 50 square meters on average allows you to get about 60 kilograms of crayfish per year, which provides a profit of $ 600.

On the practical side, you should start breeding crayfish as a business only after analyzing the demand for products, but it is important to consider that you will be able to make the first deliveries no earlier than in a year and a half. Therefore, market research should not be confused with the conclusion of preliminary contracts. Your potential buyers of live crayfish may include:

Pubs and restaurants;
Food delivery services;
Private individuals;
Seafood shops;
Supermarkets.

For each of the categories, you will need to collect information about interest in a similar product, volumes and terms of supply, on the basis of which it will be possible to draw a conclusion about the profitability and the most optimal scale of the enterprise.

Growing technology and organizational issues

As for any kind farming, it is necessary to start growing crayfish only after a deep study of the vital activity of the animals themselves. Therefore, before investing, it is advisable for an entrepreneur to start working in this area, at least on the catch.

Common ways to grow crayfish

There are several basic ways to breed crustaceans, the choice of which depends on the initial conditions (climate, availability of available territories and equipment), as well as the planned scale of production. The most popular and cost-effective are:

Open natural ponds. This method is the least expensive, but has a high risk of poaching and the difficulty of controlling brood. Also, in natural reservoirs it is impossible to influence the temperature of the environment, which is especially critical for regions with a cold climate.
Artificial open reservoirs. If you have a large enough plot of land, you can equip your own pond in a protected area. It must be at least 1.5 meters deep. The recommended area is at least 30 square meters. The bottom of such a pond should have a spherical shape. Also, so that the water does not leave, it is sealed, and then covered with a layer of sand and gravel, in which the crayfish can equip their holes.
Home aquariums. In this case, you will need at least 3 containers of 250 liters each. This is one of the least profitable ways, since it is difficult to grow a large number of arthropods in aquariums.
Recirculating water supply systems (RAS). They are polypropylene pools with built-in filtration systems. most progressive and effective method to create a full-fledged farm that allows you to grow crayfish all year round, without immersing the latter in hibernation. When using RAS general term cultivation of adults is reduced by about a third.

Selection of species for breeding

Each breed of crayfish differs in the intensity of growth and the requirements for climatic conditions of detention. Therefore, when planning crayfish breeding at home, it is very important to choose the most optimal species for your chosen breeding method. Among domestic farmers, the following breeds are most popular:

Cuban blue- a specially bred breed of crayfish, characterized by very fast growth (the minimum level of presentation is achieved within one year) and unpretentiousness. Females of this species can lay up to two hundred eggs, from which young crustaceans hatch after three weeks. During this period, the water temperature should be at least 25°C. Suitable for breeding in open reservoirs of the southern regions, aquariums and RAS.
broad-toed crayfish - unpretentious breed, capable of living and reproducing in water with a temperature of 16 ° C. It is distinguished by a large amount of meat, but today it is a rare endangered species, which complicates the purchase of young animals.
Australian- heat-loving fleshy breed (not lower than 22°C). Suitable for growing in pools, where it can grow up to 150 grams per year.
Marble- one of the most prolific breeds, which is achieved due to the lack of separation of individuals into female and male. He likes a warm climate (from 20 ° C), but it grows to a marketable appearance for at least two years.
Long-toed European crayfish- unpretentious (from 19°C) and rapidly breeding breed, suitable for open water bodies of the European continent. It has a low percentage of cannibalism in comparison with more heat-loving species, which simplifies the maintenance process.

Breeding crayfish is a painstaking task that requires a lot of patience and time. People breed crayfish for themselves or for sale. If you like seafood and want to eat plenty of crayfish, then the breeding area should not be large. If you want to breed crayfish in order to make an income, then you need to be more careful about this issue and find a suitable location. By the way, breeding crayfish is a fairly profitable business. Crayfish are valued by many gourmets who are willing to pay a lot of money for a quality product. In Russia, this industry is not developed and it will not be difficult to occupy a niche. The main thing is to create conditions under which the cancer will grow, get fat and feel great.

How long do crabs grow

I would like to note that breeding crayfish is a long-term business. Cancer from the moment of birth grows to its own maximum dimensions for 4 years. Therefore, you need to be prepared for the fact that you will receive the first profit no earlier than a couple of years after the start of growing crayfish. And all this time they will need to be fed and maintained.

Where to breed crayfish

The natural habitat for crayfish is small ponds that do not freeze through in winter. The water in them does not need to be filtered - the flowing pond provides the animals with everything they need - the optimal temperature for life and food. However, finding such a natural pond is quite difficult. Even if you live on a plot of land, digging a pond will not be enough. In winter, all crayfish will simply die from frost. Therefore, when creating conditions for breeding crayfish, it is necessary to take into account the peculiarities of their life. So, where can you keep crayfish?

In a swimming pool. This method is suitable for those who have their own pool in their backyard. You will also have to give up swimming in it for the next few years, as crayfish grow long enough. The pool should be divided into two parts. Adult crayfish will live in one part, and young ones will live in the other. This is done so that adults and strong individuals do not eat young crayfish. As soon as the cancer gets stronger and is ready to move into the "adult" pool, it is moved.
In aquarium. To breed crayfish, the aquarium must be very large. Because there is no reason to breed 10 or 20 individuals, you need to grow at least 200 crayfish to get a tangible result. If you want to breed crayfish in an aquarium, you need to buy a container of at least 500 liters. You also need to organize regular water filtration, which ensures the normal functioning of crayfish. In any living room for crayfish, it is necessary to create the optimal temperature. Whichever place you choose to breed animals, the temperature should not fall below zero degrees Celsius, otherwise the crayfish will die. If you can organize a temperature of +15 degrees for crayfish, that's great. In this case, they will not hibernate and stop growing.
In the basement. Some people successfully grow crayfish in the basement. And what? It is very comfortable. A large area allows you to place fairly large vats or aquariums with crayfish. In the summer it is always cool in the basement, but not cold in the winter. If you want to mimic the natural environment, you need to sprinkle sand on the bottom of the water tank. Also place stones in the vat that crayfish like to hide behind.
In the annex. If you do not live in an apartment, but in a country house, you can grow crayfish in any outbuilding. Even the most collapsed barn is suitable for this business. The main thing here is that it should not be cold inside, especially in winter. Insulate the extension and calmly breed crayfish there.

How to breed crayfish at home

So, a place for breeding animals is chosen. What's next? Let's deal with everything in order.

When breeding crayfish, you will have to spend money on the animals themselves, water vats, filtration systems, and also on food. But most of all you need to invest attention and patience. When breeding crayfish, it does not happen that you throw the crayfish into a vat and wait for the profit. To get a real result, you need to love this business and give it all your time. And then you can not only enjoy delicious and tender meat, but also get a considerable income.

Video: breeding crayfish at home

Crayfish breeding is an excellent startup that allows you to earn decent money for the whole family with minimal investment. The business has long been popularized in Turkey and the United States. In our country, crayfish breeding as a business is not very developed, but it is worth considering as one of the options for starting your own business.

So, what is needed for breeding crayfish:

pond or special containers;
productive individuals of cancer that can give offspring;
availability of special equipment for creating a microclimate;
crayfish food;
time.

As in every business, crayfish breeding is a matter that must be treated responsibly, it requires strict compliance with growing technologies, regime, discipline.

The cultivation of crayfish is a large-scale production, it can be organized both in large volumes and in small ones. Options for withdrawing even at home are being considered. The business is not too costly in terms of money, but it requires a careful attitude to resources and a scrupulous approach to cultivation, since slight inattention can turn into a loss of investment.

Ponds for breeding crayfish.

The main place for breeding crayfish are reservoirs. They can be natural or artificial. It should be noted that regardless of whether the reservoir is artificial or natural, it must be insulated, since in severe frosts all crayfish can die. Reservoirs can be built based on financial capabilities:

pool;
aquarium;
pond.

Pool

The most favorable option is a pool that can be covered during winter periods, which will increase productivity by 2 times, since the crayfish will not hibernate. If you build up to 4 such pools, then from one breeding cycle you can get up to four hundred crayfish. To make a pool for crayfish with your own hands, you need to pave the bottom of the tank with large gravel and pour clay.

Aquarium

For small volumes of production, it is possible to make a regular aquarium for breeding crayfish. But one should not expect a good return from it, and there will be more problems with the creation of natural conditions: crayfish need clean water, which will have to be cleaned regularly. When growing crayfish in an aquarium, cannibalism problems can arise: smaller individuals must be kept in a separate container, as they will be eaten by larger crayfish. You need to know that expensive fish and squid should not be added to aquariums where crayfish are kept.

Ponds

The most inexpensive way is to breed crayfish in your own ponds. It practically does not require investments, but the financial return will not be so high, since in the cold season the crayfish will hibernate, respectively, growth and reproduction will not occur as quickly as in piece reservoirs. In swampy areas, crayfish are also well grown. With a small pond and abundant food around - grass and algae, crayfish can create their own habitat and create income for you without investment at all, you just need to catch them and find a buyer for the products. Still, it makes sense to organize industrial breeding of crayfish in closed water bodies, since it will create guarantees for the stability of the microclimate and conditions for reproduction.

How to grow crayfish

When drawing up a business plan for breeding crayfish at home, you need to take into account the fact that you can grow the size you sell in a few years. After preparing the breeding tank, crayfish are launched into it. Water must be purified and of high quality, so it will need to be changed several times a month. To provide easy way replacement of water, it is necessary to foresee the system of descent and supply in all containers. Water intake can be carried out from a well or reservoirs with clean water - rivers.

The water does not change completely, it is necessary to constantly add about 30% of the capacity, which will renew the balance of oxygen in the water and provide the necessary balance. minerals. Be sure to read the special literature on how to grow crayfish. You must know all the nuances of feeding, growing, breeding.

If a business plan is drawn up for breeding crayfish in an aquarium, the real offspring must be taken into account. If a female can produce up to 200 crustaceans per year, then only 15% will remain alive and grow to the desired size. Many crustaceans will be eaten by their relatives, who will not disdain the young in the absence or insufficient quality of the feeding offered to them. In order to prevent this from happening, all females must be placed in separate tanks, and as soon as small crustaceans hatch, it will need to be removed and the offspring allowed to grow.

Young animals need to be fed the same foods as adults. As a rule, meat, dead fish, vegetables and bread are used. Of course, there are special foods for crayfish on the market, but in this case, it will be necessary to plan additional costs in the business plan for breeding crayfish.

The main thing you need to know is the mandatory composition of the feed:

fats;
vegetables with a lot of fiber;
crude and digestible protein;
minced fish and flour;
calcium supplements.

Where to get crayfish?

Growing crayfish as a business involves the constant purchase of female and male individuals. You can immediately purchase only females that will already be carrying eggs. If it is possible to take females from open water, then you won’t have to buy at all, you just need to carefully collect and transfer to the place of cultivation.

There are companies that have already established a crayfish breeding business, they offer individuals for sale.

Depending on the type of cancer, there are different ways content.

Australian cancer

It differs from the rest in its claws, which are quite fleshy. This crayfish wants to live in a warm environment, so it will be easy to grow at home. It is also necessary to provide a pool in the aquarium and the ability to go to the surface. The crustaceans need to build as many holes as possible, because they need a separate place for eating, a separate place for sleeping. After molting, the crayfish will need to hide in a hole, and the deeper it is, the better. Australian crayfish eat fish and algae. They also do not disdain bread or feed.

blue cuban crayfish

Such crayfish can be grown in open water, as it is quite unpretentious. The main condition is to provide a temperature of 26 degrees and constant bait. This cancer is fast growing, it reaches the size required for sale in just six months. Breeding such crayfish in an aquarium is possible, but the bottom should be sandy and covered with hard plants. It is also necessary to provide good filtration and create many minks.

marble crayfish

This species is as finicky as the Australian. He needs to create 20-28 degrees, he must feed constantly and plentifully. This cancer is quite large - it grows up to 15 cm in length. The elite breed is more expensive and profitable.

Far Eastern and European crayfish are bred in Russia, it is better to breed the latter type at home. They have their own 2 subspecies - broad-toed and long-toed crayfish. The first one is more valuable due to the presence of a quality belly. This species can be bred in open areas throughout Russia. This species is picky, it feels good in cold water with a temperature above 4 degrees, and in warm water - up to 28 degrees, it will be comfortable for it.

Crayfish feeding

IN natural conditions crayfish feed on everything they find at the bottom of the reservoir. It can be the remains of fish, algae, insects, worms, small crustaceans and, in general, all organic debris. Since all crayfish are cannibals, it is necessary to ensure constant and proper feeding. Food must be thrown into a container where crayfish are grown, once for several days. The presence of algae will provide the diet with the necessary minerals and elements, it is especially important that there is enough calcium in the feed, since it is the main substance for the formation of the shell of crustaceans. Feed is thrown into the feeding cages. It is desirable that the size be approximately 40 by 40 cm. If the water warms up above 7 degrees Celsius, it is necessary to add meat and earthworms to the food, in addition to vegetables. Too much food is also bad. If the water blooms after overflowing with food residues, it will be necessary to clean it. If the situation is not very critical, it is necessary to add earthworms to the water, they will be able to correct the situation.

Recipes for homemade crayfish or shrimp food

Feed recipe #1. To formulate the feed, the following components will be required: frozen spinach, peas, chard, carrots, dried nettle and sea almond leaves, soy flour from a health food store, trout compound feed (or pellets for aquarium fish), dried amaranth, calcium carbonate, chlorella and spirulina powders. All this should be crushed in a mixer until a homogeneous mass is obtained. Then the gruel is laid out in ordinary ice molds and placed in the freezer compartment of the refrigerator. Before feeding, break off the required amount of food, a single dose of which depends on the number of crayfish or shrimp. But it is not worth preparing dry mixes: due to contact with atmospheric oxygen the nutritional value such a mixture will steadily decline over time.

Feed recipe number 2. Spinach leaves, carrot and cucumber rings, slightly stewed in the microwave - this is a real delicacy for all decorative decapods. It is possible to lure even the most shy crayfish or shrimps out of hiding in daylight.

Feed recipe number 3. Spinach leaves, rings of carrots, pumpkin and cucumber slightly stewed in the microwave or scalded with boiling water, crushed fresh corn and green peas, boiled rice, oak leaves, Jerusalem artichoke, almonds, banana pulp, dry vermicelli, calcified cottage cheese, bloodworm. For 0.5 liters of milk - 1 ampoule (10 ml) of calcium chloride - heat until curdling, let stand for 6-10 minutes, decant through a couple of layers of gauze. The resulting mass can be frozen - thinly spread over polyethylene or foil. Suitable for both invertebrates and many fish.

Capturing crayfish

As a rule, the colonization of crayfish in the growing tank occurs in early spring. In the middle of summer, it can be observed that females bear eggs. After the young grow up and throw off their shells for the second time, they must be caught and relocated to other tanks so that they do not freeze. A new home for small crustaceans should be warm. If you wait 2 years, then the young will gain sufficient size and income will be much higher. One-year-old crayfish should be caught and transplanted into special reservoirs in which they can build up mass. The required cancer weight, which is up to 500 g, is gained in approximately 2-3 years. By this age, cancer grows up to 10 cm in length - this is a commercial product that is subject to further sale.

How to properly extract crayfish

Catching crayfish in ponds is done with special nets, fishing rods or cradles.

Catch, as a rule, until the end of autumn. The easiest time to catch crayfish is in the summer when the nights are warmer. The fastest catching of crayfish is the descent of water, but it should be resorted to only when the young are completely removed. Otherwise, he may die.

Difficulties in breeding crayfish

The most difficult thing to face during the breeding of crayfish is monitoring the quality of the environment - water. First, it must be saturated with oxygen. As mentioned above, for a sufficient amount of oxygen, it is necessary to fill in 30% of water, this will saturate 1 liter with up to 5-6 mg of oxygen. Hydrogen needs 7-9 mg per 1 liter of water. Special devices allow you to measure the number of these elements in numbers. Equally important is the presence of minerals. There are also indicators that show how much calcium and silicon are in the water. If these substances are not enough, the cancer shell will not harden. The main source of calcium is algae, which must be constantly added, as they are food for crayfish and will decrease as they are eaten. On the surface of the pond, it is necessary to ensure the rate of water replacement, which is 50 liters per minute per 1 thousand m. sq.

If the reservoir is dirty, you risk losing all individuals, because in such conditions various bacteria develop very quickly, leading to cancer diseases. The most terrible of them are: plague, porcelain and rusty disease. Firstly, they can be easily diagnosed, since the appearance of the shell will be changed, and secondly, this will affect the fertility of individuals. Diagnosis must be made by a veterinarian. To avoid infection of new crayfish, they must be transplanted into a quarantine tank after being caught.

And now, let's calculate the profitability and payback of breeding crayfish.

Now that you have read such a volume of information about growing crayfish, let's try to approach our business “more closely” and calculate the revenue and, most importantly, the profit of this business. Let's try to approach the matter seriously, as we plan to grow our crayfish in the RAS. RAS - installations of closed water supply. Our RAS is a module in the form of 6 containers, their total volume is 1.5 m3. The dimensions of each container are 1.5 * 0.75, the height of the sides is 0.25 m, the lower one is 0.35 m. Electricity consumption is 81 W / h.

By the way, you can grow lobsters in the RAS. To contain 100 kg of lobster, a volume of water in a RAS of 250 liters is sufficient. at a temperature of 5-10 degrees with a water circulation of 1000 l / h.

The RAS is equipped with: a circulation pump, a UV lamp, a compressor with an accumulator, a water heater and instructions for assembly and operation. The cost of such an installation is 60,000 rubles. Shipping is not included. Such an installation can be done by yourself, many cancer growers do this. Below we will calculate how many such installations we need to purchase and what area of \u200b\u200bthe room will be needed.

Initial data

The Australian Red Claw Crayfish (Cherax quadricarinatus or Red Claw crayfish or Red Claw Cancer), or AKKR, is a species of freshwater crayfish found in the rivers of northwest Queensland and the Northern Territory of Australia.

We plan to produce 5000 kilograms of AKKR per year or 417 kilograms per month. Crayfish growing period for sale is 9 months, average weight- 80 grams. Then it turns out that we have the declared volume, we should be born in a month 5212 rachat. Let's put 20% on mortality and get 6255 rakats per month. The stages of caviar development are determined by its color:

1st stage - light cream 1-3 days at 28°C
2nd stage - dark brown 12-14 days
3rd stage - the appearance of eye points - 20-23 days
4th stage - orange-red - 28-35 days
5th stage - descent of crustaceans - 35-40 days

Organizational plan of the enterprise for breeding crayfish:



1. Finding a room
2. Conclusion of the lease agreement
3. Conclusion of a contract for equipment
4. Renovation of the premises
5. Equipment installation
6. Water treatment
7. Buying crayfish and launching them into the water
8. The beginning of mating crayfish
9. The appearance of the first offspring and their growth
10. Start selling crayfish

Now let's calculate how many females and males of crayfish we need in order to receive such a number of rachat per month. The female brings offspring once every ninety days, the average number of crabs is 200 pieces, or 800 racats per year. Then it turns out that in a month we have 6255 crayfish born, we need 375 crayfish females for our business. Just in case, we add another 20% - we get 450 pieces. For every three females, one male or 150 crayfish males.

Thus, the number of crayfish can be about 6255 * 9 + 450 + 150 = 56895 pieces.

The planting density of “family crayfish” will be 20 pieces per 1 m2, the total density, taking into account the young, is 50 pieces per 1 m2. Then we need 56895/50 = 1140 m2 of bottom area in RAS. The area of one of our RAS is 1.5*0.75*6=6.75m2. It turns out that we need 169 installations. The total cost of 169 RAS will be 10,140,000 rubles, including delivery and installation of 10.5 million rubles. Other equipment - 500 thousand rubles.

The total investment is presented in the table below.



Purchase of equipment
working capital
Premises renovation
Buying crayfish
Organizational expenses
Total expenses

The area of tanks is 1141 m2, we add 25% for passages and additional areas for production, we get the required production area equal to 1426 m2.

The cost of renting a warm room in the suburbs will be 50 rubles / m2, excluding utility costs for electricity and water. The cost of repairs is laid at 2 million rubles.

Business revenue for the planning period of 2 years amounted to:



Proceeds from the sale of crayfish
Total revenue

Fixed and variable costs for the same period are:



fixed costs
Wage
Payroll taxes
Rent
Depreciation
Accountant services
Variable costs
Crayfish food
Communal expenses
Transport

Insurance IP
Other variable expenses
Total cost

According to our calculations, it turned out that 14,539 thousand rubles will be needed to open a business and keep it afloat for the first and partially second year. The simple payback period for this business is about 11.5 years.

To grow crayfish or not, it's up to you. Business is not easy, do not believe anyone who says that in two years you will be earning millions. The madness of the brave...

They construct various reservoirs and ponds, used not only for watering and irrigating the soil, but also as a breeding ground for crayfish. To understand how profitable and useful this business is, you need to look deep into the process of breeding crayfish.

Benefits of Crayfish Breeding

Empty ponds and water trenches filled with crayfish can be a great source of income for any family. It is known that arthropods are valued for their high-quality and healthy meat containing a large amount of protein. Dishes from them are served in many restaurants around the world, various salads, sauces, side dishes are prepared from crayfish meat and served as a main course. All this indicates that a homestead with crustaceans can serve well and bring considerable profit, but this is only possible after 5 years of investment and work. Despite this, after the first settlement of the pond, the fruits of the work will delight the owners for another 10 years.

About crayfish

Getting to work on self-cultivation of crayfish in your own reservoir, you need to understand the varieties, biological processes, features and methods of raising both young animals and adults. On the territory of our country there are several types of arthropods, which differ little from each other. Crayfish are animals that breathe with gills and have 10 legs. The shell is quite dense and covered with chitin. The most famous within Russia are broad-toed crayfish, whose claws, in comparison with the rest, differ in width and power. There are also long-clawed (narrow-clawed) and thick-clawed crayfish.

Creating a favorable habitat for crayfish

Under natural conditions, crayfish prefer to stay in calm running water, located mainly on the shady banks of rivers, lakes and canals. Ten-legged animals settle in burrows formed under the roots of old trees and plants that are in the reservoir. Crayfish are very demanding in relation to the purity of water, therefore, even at the stage of planning a pond, it is necessary to ensure that the water changes as often as possible and is not subjected to heavy pollution and flowering. Also, do not forget about the oxygen saturation and water temperature (should be 17-18 degrees Celsius), intended for breeding and breeding crayfish at home. When starting the construction of a reservoir, you should purchase sandy soil or rocky soil, in which they like to settle down so much. crustacean creatures. River inhabitants that fill the reservoir get along well with trout, which is not their food competitor.

Feeding crayfish

In addition to creating favorable conditions for normal life and reproduction, arthropods must be provided with a sufficient amount of food. Asking the question of what river crayfish eat, you can find a definite answer: everything.

Being omnivorous creatures, they eat any food they meet on their way. Particularly popular in their diet are plants growing along the banks of rivers and lakes and containing lime: reed, reeds, hornwort, and so on. Also, crayfish prefer the protein presented in vivo in the form of snails, small fish, worms, various insects and tadpoles. A creature's diet changes with age. It moves from smaller and plant food to the larger and animal.

Walking around the markets in search of what to feed crayfish, you can buy food. Today, there are various compound feeds created to feed river dwellers bred at home. Often these supplements contain a high percentage of germinated wheat and other cereals that replenish natural needs crustaceans and do not pollute the water space. Optimal ratio beneficial vitamins and minerals provides complete and healthy complementary foods. The herbal ingredients that make up the feed help to resist various diseases found in crayfish. In the process of organizing the diet, it must be remembered that river crayfish eat quite a bit, so it is better to underfeed them than to overfeed them. An excess of nutrients in a pond can lead to their decomposition, pollution and clouding of the water, as a result of which all the inhabitants of the pond begin to die.

Raising crayfish

The water temperature in the reservoir in the summer should fluctuate between 15-20 degrees. There should be 2-3 containers on the territory, installed for the purpose of transplanting young animals from their large relatives, capable of devouring the younger generation. You can also purchase an artificial reservoir, which is presented on the market in a large assortment: pools, ponds, and the like. The main task of the purchased structure is to ensure rapid water circulation, therefore its shape should be oblong, and the depth should not exceed 7 meters. Small pools and aquariums are mainly used for breeding and hatching larvae from eggs, after transplanting the females into prepared containers. The material in which the crayfish will be located must be harmless, so metal dishes should be replaced with plastic or organic glass.

Building a reservoir for crayfish with your own hands

If it is not possible to purchase a ready-made reservoir, you can build an artificial one yourself. Building a pond for such a creature as crayfish at home is a rather laborious task. First you need to choose a place for construction, next to which there is a lake, river or pond. Otherwise, the cost of an artificial reservoir will increase significantly. An important role in construction is played by a waterproof bottom, on which the entire future structure will depend. At the bottom, special waterproof and waterproofing layers are usually placed to protect the pond from leakage. In the first years of breeding crayfish, it is recommended to use a purchased tank, which is distinguished by reliability and a longer service life.

The benefits and harms of crayfish

Very few fans of eating a sea dinner know how many useful vitamins and elements river crayfish have. The benefits of breeding crab relatives in the backyard are obvious, and since they live only in a clean environment, they can be consumed without any fear. In addition to rapidly digestible protein, cancer meat contains a large amount of calcium, iron, phosphorus and cobalt. Wide spectrum vitamins such as E, D, B, C, sulfur and folic acid are found in their meat. Nutritionists recommend eating crayfish while on a diet, since their meat is a fairly low-calorie product - only about 80 kcal is contained in 100 grams of the product. Doctors also advise including cancerous meat in the diet if there are disorders in the functioning of the kidneys, heart and gastrointestinal tract. By eating crayfish for some time, you can cleanse the liver and remove bile from the body. Iodine, which is in large quantities in them, serves as a prophylaxis of the thyroid gland.

River crayfish: contraindications

Speaking of contraindications, it should be mentioned that arthropods are prohibited for people who have individual intolerance. Also, allergies can cause seafood, and in particular crayfish. The benefits and harms of cancers are incomparable concepts, since the number useful substances, vitamins and macronutrients in the meat of the creature far exceeds the harm and any of its shortcomings.

Crayfish are invertebrate animals. enjoy in great demand all around Russia. Natural populations of crayfish are decreasing every year due to poaching and disease. Natural stocks of crayfish reach a 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 the way. Crayfish were brought to these countries from the former Soviet Union. Each year, these countries supply up to 11 thousand tons of commercial crayfish to the foreign market. Spain, Portugal and China are also involved in the supply of crayfish.

In country and backyard ponds, you can successfully breed fast-growing species of crayfish, such as broad-toed and long-toed. Ordinary crayfish live in rivers, lakes, ponds, floodplains, streams with clean soft water, on clay, sandy, peaty, but not rocky bottoms. Favorable water temperature for cancer 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 the coastline of the reservoir with inlets, where aquatic vegetation grows well.

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

Usually crayfish make holes on steep shady shores, where there is little sun. Reeds, willows, acacias, 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 coast, depending on temperature.

Crayfish dig holes with the help of legs and tail, relying on the front claws. Crayfish tails are needed not only for digging holes, but also for swimming. They swim backwards and at the same time beat the water with their tail. In acidic water, crayfish, as a rule, do not live. The optimal amount of oxygen dissolved in water for crayfish is 7–8 mg/l. Perhaps a short-term decrease to the level of 2-4 mg / l.

Usually 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, not very rotten, young stems of reeds, water lilies and other plants. Crayfish are especially willing to eat algae rich in lime, which, like the peel of shells and slugs, goes to form a shell. The shell consists of chitin - 46.73%, calcium carbonate - 46.25%, calcium phosphate 7.02%.

Crayfish females always sit in burrows alone, and males often gather in groups during wintering. Crayfish are dioecious animals. Long-toed crayfish males 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 genital organs lying on the chest side, on 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. In the ovary of the female already in September, from 100 to 300 yellowish testicles are formed, in the male at the same time the vas deferens begin to increase greatly, 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. The duration of mating is from 15 to 20 days. Fertilization takes place 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-toed species of females crayfish length from 7 to 8 cm reaches 68 pieces, long-toed - 60 pieces. In the broad-toed species of female crayfish, 8 to 9 cm long, the number of eggs reaches 93 pieces, in the long-toed species - 102; in the broad-toed species of female crayfish from 9 to 10 cm long - 163 pieces, in the long-toed species - 174. In the broad-toed species of female crayfish from 11 to 12 cm long - 302 pieces, in the long-toed species - 350 pieces. In the broad-toed species of female crayfish, 13 to 14 cm long, there are 425 pieces, in the long-toed species, 500 pieces.

Caviar quickly sticks under the abdomen to the spoon legs and remains there until the larvae hatch. Since the eggs must be continuously washed with oxygen-enriched water, the female drives the water with a splash, bending and unbending the end of the tail. Calm water, if the female sits in a hole, stagnates, depleted of oxygen and the eggs die.

Crayfish caviar can be easily damaged by water scorpions, swimmers, smooth beetles. The female constantly cleans 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 the region. As a rule, hatching occurs at the beginning or in the second half of summer.

Externally, crayfish larvae differ little from adults, with the exception of size. The length of one-day larvae reaches 9-16 mm. At first, they remain attached under the abdomen of the female and hold on to the leg-like appendages of the mother with claws. After 10–12 days, they begin to swim near the female, but in case of any danger they hide under the belly. 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 up to 7-9 cm, at the age of three years - 10-12 cm; by the age of five, 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 up to 10–11 cm or more.

Juveniles reared 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 commercial length of 10 cm, 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 underyearlings in ponds with a good food supply during the vegetative period is much higher (85–90%) than in natural water bodies (10–15%). The high growth rate and survival of juveniles are explained by the good food and temperature conditions that they find in artificial reservoirs. In the rivers, juveniles do not receive even the minimum diet that covers the energy spent on searching for food and metabolism in the body.

Under natural conditions, the maturity of crayfish occurs in the third year of life with a minimum size of females of 6–7 cm. A 10-cm crayfish of a four-year-old crayfish can already be considered a producer. The timing of mating depends on the conditions in the reservoir and water temperature. In some regions, this happens 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 under such conditions 10–14 days after hatching.

Under natural conditions, crayfish go through the following stages of development. The first stage: the duration of development is from 1 to 7 days, the size of the larva is 1.5–2 mm; second stage: duration of development from 5 to 8 days, larva size 8.7 mm, weight 14.7 mg; third stage: duration of development from 9 to 14 days, larva size 1.2 cm, weight 34.7 mg; underyearlings: duration of development up to 90 days, larva size 3 cm, weight from 8 to 19 g; two-year-olds: larva size 6 cm, weight 32 g; sexually mature: the duration of development is three years, the size of the larva is 6.7 cm; sexually mature: the duration of development is 10 years, the size of the larva is 9–10 cm, and the weight is 50 g.

Depending on 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, the female is 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, the female 63.4 mm.

Some methods of breeding crayfish

Since the testicles come out already fertilized, the main concern should be concentrated on the female carrying the testicles, placing her in a safe room where she can be fed until the young crayfish fall off 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 different practices for breeding crayfish. In some farms, crayfish are grown in waterproof wooden boxes made from 5-centimeter boards. The length of the box is 12–15 m, the width is 6 m, the depth is 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. Along the walls of this pool, small cells with a volume of 5 cubic meters are arranged on several floors. The cells are placed one above the other in such a way that the walls of the pool make up their back wall, and the front of the cell must be open 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 greasy, marl clay are poured with a layer of 90 cm in height and planted with reeds, watercress and other plants. After the device, the pool is filled with water and more than a thousand females with fertilized eggs are placed in it. Crayfish are fed with waste of finely chopped meat, young frogs, fish meat, etc. Water flows in a direct current stream 25 cm thick and leaves through a drain 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 develop a strong shell.

Under natural conditions, a female is rarely found with more than 20 crustaceans on the tail, and some of these twenty themselves fall off prematurely, others die, so that on average each female grows 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, the following method can be used. Shortly before the crayfish hatch from eggs, the females are placed in a vast pond, divided by two grids into floors. The cells of the upper mesh are quite large; after falling away from the mother, the crustaceans 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 selective about water, and it often happens that they begin to crawl out of the water immediately after placing them 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 the water, and feed them there. If after that they are released into the wild, then 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 influx, rapid growth of crayfish can be achieved by artificial feeding.

In order to increase the reserves of crayfish and the cancer productivity of water bodies in ponds and other natural water bodies, it is necessary to conduct a proper economy, which involves biotechnical measures in rivers and reservoirs and artificial breeding of crayfish in ponds. In pond crayfish breeding, cancer productivity is understood as the growth of crayfish during the growing season per unit area.

To determine the value of the cancer 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 production, and the increase due to natural food and feed brought into the pond for feeding crayfish is called total cancer production. In natural reservoirs, cancer productivity is understood as production, that is, the catch of crayfish per year per unit area.

The catch of crayfish obtained from natural food in water bodies depends on the availability of food and the extent to which it is used. The formation and development of food in water bodies depends on environmental conditions that contribute to the intensity of life processes. As a result of complex biological processes at the bottom of the reservoir, microorganisms destroy the organic matter of the sludge, release the oxidized elements of the ash part of the sludge, enrich the water with mineral salts and create 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 takes place, 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 value of natural cancer production depends on the intensity of the life processes that determine this cycle.

Food base of reservoirs

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

Dead algae are partially used by organisms that inhabit the bottom of the reservoir (benthos), and most of them accumulate in the form of organic residues. Bacteria that develop in water have an even faster reproduction rate than algae. In 15 hours, one bacterium is capable of producing 1 billion offspring. Part of the living bacteria together with living algae is 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, as a result of the activity of bacteria, organic matter decomposes rather quickly. In this case, carbon and hydrogen are converted into carbon dioxide and water, nitrogen of protein compounds is converted 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 cancers include phosphorus, sulfur and iron (blood hemoglobin). The backbone of crayfish is rich in calcium. Calculations and chemical analyzes of water show that the annual growth of cancer contains significantly more nitrogen and phosphorus than pond water, which is explained by the biological cycle of substances occurring as a result of the development of life processes in ponds. The biological cycle arises as a result of different life spans of organisms and the ability to reproduce.

The fast and intensive life process in the ponds contributes to the intensive development of organisms used by crayfish for food. However, the amount of certain salts in water does not yet determine the intensity of life processes and the magnitude of cancer productivity. No less important is the amount of certain mineral salts in the soil. Water leaches mineral salts from the soil, dissolves them, thereby preparing food for lower algae. Soil organic matter 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 soil organic matter have great importance only in the first years after the formation of the reservoir. Then, as it ages, that value is lost. In old ponds, pond silt, which accumulates at the bottom, plays the role of soil in replenishing nutrients. Protein-containing organic substances of pond sludge enter the cycle under the action of microorganisms and provide food for phytoplankton. The cancer productivity of the pond depends on the intensity of the work of bacteria that supply nitrogen and phosphorus to the water. Nitrogen promotes the growth of plants and animals, and phosphorus promotes both the growth and acceleration of the processes of decomposition of plant organisms, as well as the development of reproductive products in animal organisms.

Nitrogen compounds are deposited in pond silt and serve as fertilizer for underwater and surface plants. Part 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 catchment areas in the form of mineral salts and undecomposed organic residues. An indirect indicator of the amount of organic substances in water is its oxidizability. The degree of oxidizability is determined by the amount of oxygen absorbed by one liter of water for the oxidation of organic substances contained in it. If the oxidizability is low, this indicates that the water is poor in nutrients for the development of phytoplankton.

For pond farms, water is considered good if the oxidizability is not more than 20 mg O2/l. If the oxidizability of water is more than 20 mg O2/l, this indicates contamination of the water supply source. Such water is of little use 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 vegetable protein digestible by animal organisms. Phosphorus is found in water in the form of salts of phosphoric acid and organic compounds. The main source of replenishment of phosphorus in ponds is water runoff from fertilized fields in the catchment area. Phosphorus, assimilated by crayfish, is carried away from the reservoir and excluded from the cycle. Normal, uncontaminated sources contain up to 0.5 mg/l of phosphorus. For the intensive development of green algae, 0.2 mg of phosphorus / l is sufficient.

High productivity of crayfish breeding can be achieved if nutrients in the pond will be used by useful consumers. Of the lower algae that are part of the phytoplanton, microscopic protococcal green algae, mainly chlorella and stagedesmus, are considered useful consumers. 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. The composition of 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 eggs.

Copepods found in ponds are very valuable for breeding crayfish. They breed in large numbers in all seasons, especially in early spring, when crayfish exhausted after winter begin to feed. Branched crustaceans are also fertile. This group includes daphnia, bosmins, polyphemus, etc. The most valuable among the cladocerans are daphnia and moina, 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 the nutrition of crayfish. Mollusks and their various forms contained in benthos are of some importance in the diet of crayfish.

Harmful insects for crayfish in the pond are water beetles, bed bugs and dragonflies. Beetles attack even crayfish fry. Such beetles as a rein, pond snail, water-lover, swimmer, ilk and their larvae bring particular harm to juvenile crayfish. Adult dragonflies and their larvae feed on crayfish. Frogs and tadpoles also eat crayfish. Tadpoles also eat cake - food that is given to crayfish.

How to breed crayfish in ponds

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

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

Key ponds are supplied with water from permanent springs. Usually they are arranged by bunding a part of the valley or beams adjacent to the terrace above the floodplain, from which the springs flow. Most ponds have a uniform depth over the entire area. At the dam, they are made a little deeper - 1–1.5 m. As a rule, the water in spring ponds is cold, with the exception of large ones with a slight debit of spring water. The size of the ponds usually does not exceed 5 hectares, but larger ones are also found. The chemical composition of pond water varies greatly and mainly depends on the quantity and quality of water in the spring and on the soil on which the reservoir 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 arranged by blocking the valley with a transverse dam. These ponds have a deep part at the dam with a gradual decrease in depth towards the tops of the ponds. Such ponds usually have a well-developed coastal zone. The temperature of the water depends on the distance of the water run to the confluence with the pond, the size of the pond and the flow rate of the stream. In the sources, the water is cold, farther from the source, and in the absence of coastal springs, it is warmer than in the source, no colder than in ordinary lowland rivers. The area of these ponds is small - from 5 to 10 hectares, but may be 25-30 hectares.

River ponds are supplied with water from rivers. According to the nature of the device, they are divided into channel and floodplain. Run-of-river suit by blocking the river valley with a transverse dam. The main purpose of the dam is to use the energy of water for small hydroelectric power plants, to drive mills, hullers, oil churns, to supply water to crayfish nurseries located in the floodplains 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. To the top and along the banks, the depths go to zero.

Basically, ponds are warm and durable. The salt composition of the water in them depends on its quality in the river, the catchment area and its runoff, on the nature of the bottom bed and on groundwater inflows. Floodplain ponds are formed during the dike of the lower part of the floodplain. Water is supplied to the ponds to the level of the water horizon of the pond with the help of a bridge that raises water in the river and the channel, which is located in the elevated part of the floodplain. Such ponds are located in the floodplain of the main river, they are supplied with water from the 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 the 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). Arrange ponds by blocking wet hollows and beams with 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 the water is determined by the quality of spring water flowing from the catchment area, bed soil and groundwater. In winter, such ponds are observed to die.

Ponds with atmospheric water supply are built in the same way as ground-atmospheric ones, only they are laid in upland gullies and ravines that do not have an inflow of surface groundwater. They are supplied with water from spring and summer runoff. The area of ponds is 10–50 and 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 with flood water. From the beginning of the recession of the hollow water in the dams, shields are inserted to block the water.

Dams are located in logs above the water level in the river. They are flooded every year by flood waters. They are replenished with water due to summer runoff from the local catchment area and partly from groundwater. Basically, dams are used for breeding crayfish and for irrigation. The area of such ponds is from 5 to 100 hectares. Their shores are gently sloping, overgrown with vegetation. Steep and steep banks are rare.

When building new ponds and devices for breeding crayfish, it should be provided: a spillway that allows you to drain water and drain the pond bed for the winter or only in autumn for the time of catching crayfish, as well as a cancer-protecting top that prevents crayfish from leaving 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, first the water is 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 one are used for various needs.

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

According to their design, ponds must comply with sanitary and hygienic requirements aimed at creating unfavorable conditions for the development of larvae of the malarial mosquito. To avoid swamping of areas adjacent to pond dams, quarries are made drainable or provide a ditch for discharging seepage water and draining the adjacent area. The riverbed 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 ponds for complex purposes Special attention should be given to their depth. For breeding crayfish in the northern regions and the middle lane, the average depth of the ponds should be within 0.8 m, in the south - 1 m. For feeding ponds, such ponds are optimal. With greater depth, the production of crayfish decreases. When constructing floodplain ponds in specialized farms, smaller average depths are also allowed. In some cases, at such depths, the productivity of crayfish becomes greater.

Of great importance for the production of crayfish is the choice of sites for the construction of ponds. Ponds can be built on a variety of plots of land with various soils, provided that they can be built dams and fill the plots with water. The more fertile the soil of the pond, the higher the productivity of crayfish will be in it.

Quite often, infertile soils are used for ponds, which are unsuitable for arable land - solonchak, upland areas in beams, giving low yields of grasses, etc.

How to breed crayfish in the bays of reservoirs

From ordinary reservoirs, navigable and energy reservoirs are distinguished by strong fluctuations in the water level, especially in 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 lowering the water level in the reservoir, a zone of temporary drainage is formed. This feature is pronounced in the reservoirs of the plains with their vast areas of shallow water, which make up from 40 to 80% of the reservoir area.

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

Unlike the zone of temporary drainage, the non-draining part of the reservoirs is called the zone of permanent flooding. For the life of crayfish in reservoirs, the zones have different meaning. The zone of constant flooding is the place of wintering, and the zone of drainage, as a rule, is the place of breeding. Both zones can be successfully used for breeding crayfish.

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

Suitable for the construction of ponds, drained sections of reservoirs are floodplains of small rivers, streams, beams, hollows and other depressions, along which water flowed from the catchment area into the rivers. In autumn, these areas are drained, in winter they are frozen. During the spring flood, dried and frozen areas are again covered with water.

Bays that cut deep into the mainland and have a narrow outlet to the reservoir can be used with the least expenditure of funds. The hydrological regime of enclosed bays differs from ponds in that the bays are filled with water not directly from the catchment area, but from the reservoir, with the beginning of the water rise.

The water temperature in the ponds at this time is much higher than in the enclosed bays, since colder water from ice-covered reservoirs enters the bays. In the future, the water temperature in the bays is almost the same as the temperature of the ponds.

Fenced bays according to the conditions of water supply are divided into two groups. One group includes bays with a dependent water supply, the other - with an independent one. Bays with dependent water supply receive water from reservoirs and are not replenished with water when the water horizon in the reservoir decreases. Bays with independent water supply in spring can receive water from the reservoir, and after the lowering of the water horizon in the reservoir, they are supplied with water due to the constant inflow 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 of water release, bays are also divided into two groups - early and late release from water. Bays of early release can be lowered in autumn before freeze-up, bays of late release - only as a result of the winter lowering of the water horizon during the period of freeze-up.

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

For complete drainage of 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. In the presence of streams flowing into bays, the depths of the ponds during the period of decline in the channel part should not exceed the height of the level of the reservoirs.

How to breed crayfish in peat workings

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

In lowlands, hollows, floodplains and on lakes, 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, low-lying swamps are formed. In such swamps, the process of decomposition of vegetation residues is not inhibited. hyperacidity but a lack of oxygen. The water of lowland swamps contains little dissolved oxygen. Atmospheric oxygen is not supplied to decaying vegetation due to the layer of water covering the swamps. Transitional bogs occupy a middle position between upland and lowland bogs.

There are different ways of extracting peat, after which there are different quality outputs. With the hydraulic method, quarries look like long and wide reservoirs. If the machine-forming method is used with baggers or excavators, narrow and long pits with a depth of 3 m or more are obtained. With the milling method, when peat is worked out in thin layers, there are milling fields of a relatively large area, with a flat bottom. Such fields are most suitable for the construction of ponds. The natural productivity of ponds on them is almost twice that of ponds built on quarries, which are worked out in a hydraulic way.

Peat workings tend to have an acidic soil, with a pH of 4.1–4.4, which makes the natural productivity of pond crayfish very low unless liming is applied.

The soil of peat workings contains many organic compounds that are strongly associated with colloids of humic substances, which quickly adsorb phosphorus compounds that are 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 substances and enrich the water with nitrogen and phosphorus.

Ponds in peat workings do not differ much from ordinary ponds on peaty or loamy soils, except for the pH of the water, which ranges from 6.6–6.8. If lime is added to the soil every year, the pH of the water will approach neutral. In ponds on peat workings, the food base develops well, especially zooplankton, the intensive use of which ensures high productivity of crayfish.

How to breed crayfish in reservoirs

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

Irrigation reservoirs are arranged to retain atmospheric waters. In the spring they are filled with water up 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 decreases by almost 70% compared to the area of spring flooding.

In such reservoirs, the density of crayfish planting is calculated by 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 mirror of spring flooding. When calculating according to the maximum mirror of spring flooding with a decrease in the area of \u200b\u200bthe reservoir in summer, crayfish need top dressing.

For some industries, for example, starch and sugar factories, some metallurgical and others, industrial reservoirs are arranged. 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 filled with water during the flood. For breeding crayfish, such reservoirs are best used by methods of pond crayfish breeding by annually settling and catching everything that is grown, for example, reservoirs that can be lowered or caught by longitudinal tonya, as well as by methods of reproduction of herds that do not have conditions for reproduction that do not leave with water in spring flood time.

To catch crayfish during the construction of new reservoirs, it is necessary to provide for the installation of bottom outlets in order to completely drain the water. Large reservoirs, from which the water never drains, must be adapted for seine fishing by smoothing out bottom irregularities. To do this, remove shrubs, trees and thickets of hard vegetation and uproot stumps. After removing the stumps and stones, the pits are covered with earth; steep banks of ravines and rivers are cut at an angle of 45 degrees. If the reservoirs are populated with crayfish, it is necessary to provide for the installation of collapsible cancer barrier dams during the flood.

How to breed crayfish in shallow lakes

On the territory of the country there are a huge number of small lakes that are quite suitable for successful breeding of 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, riverbed, central floodplain (valley), terraced floodplain and dam lakes.

Usually, 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 during the day. During the day, there is a supersaturation of water 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, oxygen in the water is gradually depleted for the decomposition of algae, which die off in autumn. Oxygen deficiency is accompanied by complete death. Therefore, breeding of crayfish in floodplain lakes is carried out by spring planting and mandatory autumn catch of grown crayfish.

Floodplain lakes have an excellent forage base. Despite the long-term coverage by a significant layer of water during the flood, zooplankton retains a constant species composition. A particularly strong development of phytoplankton and zooplankton is observed after the recession of hollow waters. Benthos is distinguished by a variety of species composition and abundant development, especially of larvae, chironomids. In large quantities in the lakes there are larvae of various insects, oligochaete worms and various mollusks. The residual mass of bottom natural food of crayfish reaches 100 g per 1 sq. m. In terms of natural productivity of crayfish, floodplain lakes often surpass ponds.

Floodplain lakes are divided into several groups as crustacean grounds: discharged, non-descent oblong oxbow lakes and wide lakes of the central floodplain. The bottom of drainage lakes is located above the water level in the river, so it is easy to make them drainable. Such lakes do not differ from drain ponds; the productivity of crayfish in them can be very high.

The non-drainage lakes-oxbow lakes are oblong, of small area, they can be well processed with seines of longitudinal thinning. Among the oxbow lakes there are also very large ones, from which crayfish are caught by pumping out water with powerful pumps. Non-drainage lakes of the central floodplain usually have a large area and width and cannot be fished by longitudinal sinks either before settlement or in autumn. To catch crayfish from them is possible only by pumping out water annually with pumps. The cost of pumping water does not exceed the cost of catching crayfish with nets. Leaving the bottom of the lakes for the winter without water helps to increase their productivity of crayfish.

Floodplain lakes, which are flooded only during the years of maximum floods, often become shallow and are not used for breeding crayfish. To drain such lakes, a ditch is dug or the source is deepened enough to drain the rest of the water and leave it to fly in years of minimal floods. Some lakes are shallow due to the great depth of the channels through which the water that has entered during the flood descends. In them, the water level is raised in various ways. For example, a simple lock is being built on a spill ditch. The lock consists of sheet piles at the level of the lowest water horizon and piles, which have a lateral connection with the banks by fencing the sides with slabs, boards or planks. The space between the side walls of the lock is covered 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 open for the winter. When the spring water level rises, it freely passes through the lock and fills the reservoir.

In order to prevent wild animals from entering the reservoir, gratings with vertical rods are inserted into the grooves. When the water level begins to fall, the bars are taken out and the lock is closed with two rows of shields. To reduce water loss, soil or peat is poured between the shields, leaving them until autumn. During the autumn descent, shallow waters overgrown with hard vegetation are freed from water, which improves the conditions for catching crayfish.

How to breed crayfish in ilmens and estuaries

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

In the area where the ilmens are located, adjacent to the western part of the Volga delta, summers are usually hot, long, with an abundance of sunny days. There is little rainfall. The amount of oxygen dissolved in water in summer ranges from 6.2 to 16 ml per 1 liter. In deep-water ilmens, the oxygen content in winter ranges from 50 to 92% saturation. The growing season lasts almost eight months, the bottom of the 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, one can completely do without the construction of wintering ponds, which are the most expensive part of the crayfish nursery.

According to the calculations of specialists, when pumping out the remaining water in autumn 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 centners of crayfish. Ilmeni, which are not subject to winter freeze, are also suitable for growing crayfish. It is recommended to populate them with yearlings and catch commercial cancer not in the same year in the fall, but a year later, when a three-year-old carp reaches a weight of 2 kg. With a three-year cultivation, it is possible to pump out water and catch crayfish not from all ilmens, but from half, which will reduce labor costs by half and ensure the production of large, highly valuable crayfish.

With a three-year period of cultivation, the need for seedling material is two times less than with a two-year one. With the correct operation of the crayfish ilmens, their drainage with the help of pumping units, you can get more than 3 q, and in 2 years - 6 q per 1 ha. It is this productivity of crayfish in the Volga delta that was obtained in an ilmen with an area of 75 hectares in the Astrakhan region.

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

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

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

The area of estuaries is constantly changing. The reasons for the changes are gentle shores, shallow depths, fluctuations in the water horizon depending on its inflow, etc. The shallowness of the estuaries determines their peculiar thermal regime, characterized by rapid heating of water in spring and rapid cooling in autumn. 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 thickets during the day, the water temperature at the bottom is 7–9 degrees lower than at the surface.

In winter, the estuaries are covered with ice 15–30 cm thick on average for 75–80 days.

Many estuaries are silted, the silt layer usually reaches 0.5 m, in some 2–3 m. The salinity of the water is not constant and depends on the connection with the river and the sea. Most of the Kuban limans are desalinated, their salinity is no more than 2%, while the salinity of the Sea of Azov reaches almost 12%.

Most of the estuaries are heavily overgrown with coastal reeds, cattails, sedges, etc. Hara, hornwort, pondweeds, and urut are common underwater vegetation. 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.

At present, according to the scheme of crayfish breeding and reclamation measures for the reproduction of commercial crayfish in water bodies Krasnodar Territory the main area of the estuaries is allocated for the construction of nurseries. For the construction of commercial farms, 16 thousand hectares of estuaries and all dead-end estuaries that are not important for the reproduction of the commercial crayfish of the Sea of \u200b\u200bAzov are allotted.

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 with dense plantings and thereby increase the productivity of crayfish up to 18 centners per 1 ha.

The area of rivers can be significantly increased by arranging simple bridges on them, which make it possible to raise the water horizon and at the same time use them as headwaters to trap crayfish in a fenced-off section of the river. The areas fenced off by jumpers before planting the cancer must be carefully caught with a bullshit.

How to transport crayfish

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