Types of hydrothermal fish and sturgeon
Hydrothermal fish:
One of the prominent features of hydrothermal fish breeding is their acceptance of heat conditions. The most important species of hydrothermal fish farming in the country are:
- Chinese Carp includes: silver carp, grass carp, ordinary carp, bighead carp.
- Indian Carp includes: Catla, black ghost, kalpasi.
- Black Carp: milkfish, tench, mullet.
Physical Properties of Water:
Temperature: It is suitable for breeding hydrothermal fish above 18 ° C and they are well nourished, grow and multiply. The best growth conditions are in the range of 25-28 degrees Celsius. They will suffocate at temperatures above 33 degrees Celsius and get sick below 12 degrees Celsius and hibernate below 8 degrees Celsius.
Chemical Properties of Water:
Water soluble oxygen comes from the following three main sources: Through mechanical operations (aeration), this device injects oxygen into the water by pumping the surrounding air into the water. Oxygen penetrates the air by creating waves on the surface layers. Oxygen from photosynthetic plants in water.
The water quality section is described in detail.
Different methods of rearing Hydrothermal fish:
Fish breeding by age or size: In this method fish production is divided into three stages
Production of larval to baby fish
Production of baby fish to a baby fish weighing 10-20 grams and suitable for fish breeding.
Market fish production.
Fish breeding in terms of species composition: In this method, the breeding may be in single species, two species or several species, which if the increase in the efficiency of the fish pond, most breeders will use multi-species method.
Breeding of hydrothermal fish in terms of crop density in ponds
- Extensive and non-condensed breeding using natural water products and not using handmade food.
- Semi-dense breeding is provided by 60-90% of fish feed through fertilizer and natural feed and the rest will be manually fed.
- Dense breeding which about 50% to 60% of fish feed comes from fertilizer and natural feed, and the rest will be hand-fed.
- Super dense breeding this method is specific to high-value fish such as salmon.
Sturgeon
Sturgeon are known in the Persian language as “Taas Mahian” and in the international community by the name of Sturgeon. Also, the scientific name for this species is Acipenseridae. One common mistake among the populace is to name ‘Starry Sturgeon’ to refer to this category of fish instead of the sturgeon and ‘Taas Mahian’ names. Sturgeon is a name given to some fish in the sturgeon family, with a total of about 27 species and subspecies. Of these, 5 species live in the Caspian Sea, which alone holds about 93 percent of the world’s sturgeon stocks. The caviar is very high-calorie and energetic and its various types such as golden, red and black caviar but of course black caviar is of considerable value.
Different species of sturgeon: The sturgeons are divided into two main groups: Acipenser and Huso.
Sturgeons in the acipenser category are divided into the 6 following species:
- Acipenser Persicus
- Acipenser GueldenStaedtii
- Acipenser Nudiventris
- Acipenser Stellatus (Sevruga)
- Acipenser Baerii
- Acipenser Schrenckii
In the meantime, three varieties of ” Acipenser Persicus”, ” Acipenser GueldenStaedtii” and ” Acipenser Nudiventris” have become known as the sturgeon or Asetra.
Husos are also divided into 4 categories:
- Huso Huso (Beluga)
- Huso Dauricus (Kaluga)
Here’s a detailed description of each of the above species of sturgeon:
Acipenser Nudiventris:
The fish is named after its Latin and scientific name, and has similar characteristics to other sturgeon, including Acipenser Persicus, but because of the differences between this fish and Acipenser Persicus and Acipenser GueldenStaedtii, It can be pointed that this species is not cultivated (for economic reasons) as well as the small and small size of its caviar. Acipenser Nudiventris are usually migrants who come to the Iranian coast for spawning and lay eggs in the Caspian rivers. It has a 30-year life span, is lightweight and very small in number and is fourth in value, with a length of more than one meter and light weight, which reaches the age of 10 to 14 and spawns.
Acipenser Persicus:
The name of this fish means “Black Nose” and is known as Acipenser Persicus because of its appearance. This fish is the best species of sturgeon in the world that has recently been recognized as an independent species and is also an indigenous species of Iran. Acipenser Persicus is white in color and less fat than other varieties. Its delicious taste of caviar doubles the charm of this fish. The caviar is a golden yellow to dark brown color caviar, and it takes between eight and eleven years to produce in different environments. If this caviar is produced under ideal conditions, it will taste special like walnuts. In the first year of life, baby fishes feed on gammarus, larvae, oligochaetes and so on. The young fish feed on other fish and, when fully grown, feed on mollusks and crabs in addition to fish.
Acipenser GueldenStaedtii:
The name of this sturgeon is also called “hollow head” according to the hole in the head. In most cases it is quite similar to Acipenser Persicus, and the only differences are its flesh is yellow and its taste less than Acipenser Persicus. Many find the taste of caviar unpleasant and eat it with another food; and a group that defines itself as a genuine caviar enthusiast in the world, They believe that someone who does not like the taste of pure and cold caviar and spicy caviar is better off not letting it be eaten by mixing it with another food.
Acipenser Schrenckii:
The main name of this fish is the Shrinki, which is the last of the acipenser. This fish is Chinese-specific and takes between five and eight years to produce caviar. Dauricus Schrenckii is a combination of this fish and Kaluga fish.
Acipenser Stellatus:
Starry sturgeon means long nose and its color range from light gray to dark gray and sometimes black. It is not cultivated fish and its caviar has fine and delicate flavors that need between 6 and 12 years to produce. Starry sturgeon is last in the quality rank, as her eggs are smaller and cheaper,This fish has a problem with artificial reproduction, and the number is declining under natural conditions. Red or black caviar can be purchased at all Russian grocery stores. At grocery stores, a few red caviar seeds are served on a slice of bread with a parsley leaf. As black caviar is best known in Iran and southern Russia, red caviar has more supporters in Siberia and the Far East. Although red caviar is cheaper than black caviar, its taste and nutritional value is no less than black caviar.
Acipenser Baerii:
Like the Acipenser Nudiventris, the name of this fish is derived from its Latin name. It takes about 5 years to produce caviar, which is one of the smallest caviar types. The caviar of this fish is seen in dark gray to black. This fish belongs to the waters of northern Russia and is ideal for breeding environments due to the low time required to produce caviar. This fish resembles Acipenser GueldenStaedtii, except it has gill blades, a short, slightly flat snout and a deeper lower lip. In nature, Siberian body length reaches up to 2 meters and weighs between 56 and 200 kg and rarely exceeds 200 kg and the maximum age is up to 60 years. It is a semi-migratory fish and lives in all Siberian rivers such as OB, Yeni Sei, Lena and Lake Baikal Basin.
Acipencer Ruthenus:
It resembles a Acipenser Nudiventris fish, but is distinguished by a cut in the middle of the lower lip. Mustaches are filaments and the number of lateral bony protrusions is greater than other species of dice. Sterlet is one of the small species of semi-migratory freshwater fish that live in freshwater. It is 34 to 50 cm long in nature and weighs 6 to 8 kg and rarely reaches 125 cm and 16 kg. This fish is found in the rivers of the Black Sea and Azov and Caspian Sea but has not been observed in Iranian waters. The crossbred fish is the product of a cross between female beluga and male sterlet.
Beluga:
This fish, known in Iran as the elephant fish, has the largest, most expensive and the rarest type of caviar. Its maximum lifespan, weight and length are: 80 years, one ton and 6 meters respectively. After each egg hatching, it begins to hatch again about two years later. Between 10 and 15 percent of the weight of this fish is its sturgeon. A sturgeon that takes about 12 years to produce in the growing environment and its color range from light gray to dark gray and even black. It spawns every 2 or 3 years and matures between 10 and 17 years and named the best caviar, the most expensive fish and caviar in the world. It has a height of 1.5 to 4 meters and to this day, its catch in Iran has been more than 650 kg. The Beluga is one of the predatory fish and has been hunting in the rivers for months. At sea it feeds on the Caspian Roach, all kinds of Clupeidae, Black Sea Sprat, Gobiidae, Caspian kutum and so on. About 90% of Caspian Beluga migrate to the Volga River for spawning. The caviar of this type of fish is named according to its size. If the size of the caviar is less than 5 mm, it is called blouge, and if its size is greater than 2.5 it is called royal or imperial.
Kaluga:
This fish, which is one of the other species of the Huso family, resembles the Beluga in all cases but looks similar to the Astra. Found in the Amur River in China and, as mentioned, hybrid varieties were also produced.