Are Sturgeons Easy to Keep? Understanding Sturgeon Farming Difficulty in One Article

AbstractArtificial sturgeon farming requires creating a suitable living environment, with a growth water temperature of 20-24°C, a pH value between 7.2-8, a transparency of 20-40cm, and a dissolved oxygen content of 6-8mg/L. Do a good job in the breeding and rearing of fry, and carry out domestication and feed conversion in good time. Provide high-quality protein feed and feed at fixed times, fixed spots and fixed amounts.

Sturgeons have relatively strong adaptability and can be successfully farmed in cages and ponds. According to foreign farming trials and the physiological characteristics of sturgeons, farming in flowing water below dams, in large water surfaces, and in industrialized systems all hold great promise. However, artificially farmed sturgeons have relatively high requirements for the water environment, so it is necessary to regulate water quality well, do a good job in rearing fry, master the nutrients sturgeons need, carry out feed conversion domestication in good time, reasonably control the amount of bait, and feed according to the principle of “fixed time, fixed spot, fixed amount”.

I. Selection of the Farming Environment

Because the environmental conditions of artificial farming differ considerably from the natural living environment, during artificial farming the temperature, light, water flow and other environmental conditions can be regulated artificially, and then techniques such as physiological induction can be used to let the sturgeon's gonads develop and mature, while compound pellet feed is used for rearing.

The water quality environment requirements for farming sturgeons are relatively high, and the dissolved oxygen content needs to be between 6-8mg/L. Rectangular fish ponds with an area of 3-5 mu are the most suitable, and the pond must have a good water inlet and drainage system, a pond depth of about 2m, and bottom silt of less than 10cm. If the farming pond is a cement flowing-water pond, its area can be 50-300 m.

Before stocking, the pond needs to be disinfected with 10 kg/mu of quicklime, then dried and left to bake in the sun. Two weeks before stocking, fill the pond with water to a depth of about 2m. The size of the sturgeon determines the stocking density; generally, 500 fry of 300-500 grams are stocked per mu

. The water temperature for sturgeon survival is 1-30°C, but the most suitable water temperature for the growth of commercial sturgeons is 20-24°C. Summer temperatures are relatively high, and when the pond water temperature exceeds 26°C, new water should be added in good time. In autumn and winter the temperature is relatively low, and the water temperature must not be lower than 4-6°C.

II. Rearing Fry

The sturgeon migration begins each year in spring and ends in autumn. Sturgeons that migrate in spring spawn that same year, while sturgeons that migrate in autumn spawn the following year. The first sexual maturity of males is generally 9-11 years of age, and of females 11-13 years of age, with a spawning cycle of 4-6 years.

Sturgeons grow very fast. Newly hatched fry can reach a size of 7-10cm after 1 month of rearing. Under suitable conditions, fingerlings of 100-150 grams stocked in early spring of the same year can reach commercial fish of 0.75-1 kg after 9-10 months of rearing.

Square cement ponds or ponds made from round glass tanks can be used as fry rearing ponds. The fish pond has a diameter of 3-5m, a depth of 1.5m, and a bottom slope of 6-8%. The walls and bottom of the cement pond need to be tiled, and the water depth is 0.6-0.9m. Choose unpolluted river water with a water quality pH between 7.2-8 and a transparency of 20-40cm, and use it after sedimentation and filtration.

Control the water temperature between 20-29°C. When the water temperature is higher than 32°C or lower than 10°C, use deep well water or boiler water to regulate the temperature, and at the same time use an aeration pump to keep the dissolved oxygen content in the water above 6mg/L. Pond water is let in by spraying and direct injection, and drainage is by central overflow. According to the condition of the fry and the water quality, siphon and discharge waste from the bottom once every 2-3 days, drain and wash the pond once every 7-10 days, and promptly remove dead fish and other pollutants.

For the fry, sturgeons with a tail weight of 5-10 grams, a body length of 10-15cm, and that have already been domesticated and converted to feed can be chosen. Newly hatched sturgeon larvae change considerably in body shape and behavior, and are at the stage of shifting from body surface and yolk respiration to gill respiration; at this time sufficient oxygen needs to be provided.

III. Feed Nutritional Requirements

Sturgeons are carnivorous fish and mainly take in protein sources based on animal protein. The most suitable protein range for artificial feed is 35-49%. The fat content in feed for juvenile fish is most suitable at around 9%, and the oil most suitable for sturgeons to consume is fish oil, followed by soybean oil and corn oil.

Fatty fish have a very high ability to utilize fat, and the digestibility of fat and feed efficiency both reach as high as 90%, while for sturgeons it may exceed 95%. Carbohydrates: the digestion coefficient of sturgeons for carbohydrates such as maltose, glucose and galactose can reach more than 95%.

Minerals and Vitamins The content of compound vitamins added to sturgeon feed is about 1-2%, the content of compound inorganic salts is 1-3%, and choline is about 0.5%.

IV. Feeding Management Methods

Sturgeons have a very strong food habit, and they will refuse to eat unfamiliar food. If they initially eat water fleas and water earthworms, it takes a certain period of domestication before they will eat converted compound feed. Sturgeons react relatively slowly and are rarely affected by the outside world. During the farming process they rarely engage in strenuous activity; apart from swimming along the pond walls and bottom they have no other movement, so they consume very little energy in movement.

In order to increase the survival rate of fry, during the mixed nutrition stage before the yolk sac is fully absorbed, suitable opening bait can be fed in good time. Fry at this stage are in a passive feeding phase, so it is necessary to ensure a certain density of bait in the water, which can increase the survival rate.

Adopt the feeding principle of “fixed time, fixed spot, fixed amount”, with a daily feeding rate of 3%. As the fish grows, slowly reduce the feeding rate; when the fish reaches more than 1 kg, the daily feeding rate must not exceed 1%. Sturgeons are afraid of light, so they can be fed once each at dawn and dusk every day. In order to speed up the growth rate of sturgeons and improve their anti-stress ability and immunity, every half month the fish need to be given extra freshwater fish multivitamins, enzyme preparations, Fish Health No. 2, etc.

At the beginning of feeding, live bait such as live water earthworms or zooplankton sold on the market can be chosen; first disinfect with potassium permanganate or table salt, then feed, with a feeding frequency of 3 times/day. When the sturgeon's body length is 4-9cm and its weight is 1-4 grams, the feeding habit domestication from live bait to compound feed needs to be completed. During the domestication process, soft pellet compound feed is used in the early stage, and hard pellet compound feed is used in the later stage.

V. Common Types of Fish Diseases

1. Bacterial enteritis. This disease usually occurs at the adult fish stage, mainly manifesting as bleeding in the abdomen and mouth, red and swollen anus, and emaciation. Feed medicated bait containing 0.2% furazolidone continuously for 5-6 days, and it can be cured.

2. Fatty liver. Fish suffering from fatty liver have no very obvious external symptoms, but show phenomena that are not easy to notice, such as slow growth, poor appetite and low feed conversion, and it rarely causes death.

There are many factors that cause fatty liver in fish, mainly an inappropriate match between the main ingredient formula of the feed and the nutritional standards of the farmed species, deficiency or excess of the main feed components such as protein, carbohydrates and fat, too much oil added to the feed, deficiency or excess of certain vitamins, long-term or excessive use of antibiotics, insecticides and chemically synthesized drugs, and toxic substances in the water body.

When this situation occurs, do not feed spoiled and deteriorated feed, use drugs scientifically, do not use drugs indiscriminately or abuse drugs, and do not add drugs to feed for long-term use. Some substances beneficial to lipid metabolism, such as VB, VE and choline chloride, can be appropriately added.

3. Liver congestion and liver hematoma. Diseased fish have no abnormalities on the body surface. If dissected, the liver can be seen to be enlarged, and there are red spots and red patches on the liver; in severe cases they are red, purplish red or brown. The abnormal manifestations of sick fish are insufficient vitality, a body color that becomes dull gray, a clear decrease in food intake or cessation of feeding, and emaciation, and they are very prone to infection with infectious diseases. Under the action of pathogenic substances, the liver tissue is very seriously affected, leading to liver insufficiency.

The occurrence of liver hematoma and liver congestion is generally caused by certain drugs and toxins, or liver hematoma and liver congestion are caused by fatty degeneration; the disease-causing factors are the same as those for fatty liver. If it can be diagnosed and relevant treatment measures are taken, liver tissue lesions can be effectively controlled.

VI. Disease Prevention and Control

Sturgeons have relatively strong disease resistance and a low incidence rate. During the farming process, prevention should be the main focus, with treatment as a supplement. Only by doing a good job in disease prevention and control work can fish diseases basically be eliminated. Prevention can be carried out by combining medicated bait feeding with water body disinfection. Regularly use 20 kg/mu of quicklime to splash the whole pond, which can kill pathogens and improve water quality.

Splashing the whole pond with 0.4mg/L of trichlorfon can kill Dactylogyrus, Gyrodactylus and larval Ergasilus. In each month, feed medicated bait for the first 2 times, and feed non-medicated bait for the last time; the amount of medicine accounts for 0.5% of the bait weight. The medicines are furacilin and oxytetracycline, and if the two are used alternately, the effect will be more remarkable.