CATDOLL : CATDOLL: What does a carp look like?

Carp can spawn and reproduce naturally in flowing water or still water, but artificial breeding can achieve better spawning and hatching results.

1. Broodstock cultivation

(1) Sexual maturity and sexual cycle

Carp cultured in lakes, ponds, reservoirs, and ponds in the Yangtze River Basin begin to mature sexually at the age of two for female carp, and reach sexual maturity at the age of one or more for male carp. Generally, May is the period of their gonadal maturation and spawning. After spawning, the ovaries in stage VI absorb and degenerate to stage I in July, and then gradually develop to stage IV in November, and hibernate in this period. In March and April of the second year, when encountering suitable environmental conditions, the ovaries mature rapidly and develop from stage W to stage V. After reproduction, the testes of sexually mature male carp degenerate to stage III, enter stage IV in August and September, and enter stage V in December, and hibernate in this period.

The spawning season varies in the north and south. The peak spawning period in the Pearl River Basin in the south is February and March; in the Yangtze River Basin it is April and May; in the Yellow River Basin it is May to June; and in the Northeast it is June and July. The spawning period generally lasts about 2 months.

(2) Sex Identification

Sexing of carp.

(3) Selection and breeding of broodstock

Female carp should be over two years old and weigh more than 1 kg, while male carp should be slightly smaller, weighing about 0.75 kg. The selected broodstock should be tall, thick-backed, strong, slightly long, active and uninjured. The source should be lakes, net enclosures, outdoor ponds, and ponds, which are pollution-free and high-quality broodstock.

The area of ​​the broodstock pond is generally 3-4 mu, with a water depth of about 1.5-1.8 meters. It is necessary to clean the pond once a year. The stocking density of broodstock is generally 150 kg/mu. A small amount of silver carp and bighead carp can also be mixed to control the excessive reproduction of plankton. Male and female broodstock must be raised separately before spawning after wintering to avoid temperature rise. When there is a sudden heavy rain, carp will reproduce naturally and spawn sporadically. At other times, male and female can be raised separately or in the same pond. Carp is an omnivorous fish with a large appetite. Sufficient food should be given during the breeding period. At the same time, appropriate fertilizers can be applied to make the water fertile, natural bait can be supplemented, and attention should be paid to the use of high-quality feed for intensive cultivation 15-20 days before spawning to promote the development of gonads.

2. Natural fertilization of eggs

(1) Selection of spawning and hatching ponds

The spawning pond is preferably 2 mu, with a water depth of about 1.2 meters. It should be sheltered from the wind, facing the sun, with less silt at the bottom of the pond. It should be convenient for water inlet and outlet, and have a quiet environment. 3-5 days before releasing the broodstock, clean the pond with quicklime, etc., filter it strictly when filling it, and ensure that the water is fresh and has a high oxygen content of more than 5 mg per liter.

Generally, the pond used for raising fry also serves as a hatching pond. If it is used as a hatching pond, there must be 3-5 ponds that are rotated to make it easy to operate during hatching. The required pond area is 2-3 mu and the water depth is 0.8-1.0 meter, but the pond must be cleaned before releasing the fish.

(2) Production and setting of fish nests

Carp lays sticky eggs, which need attachments for the fertilized eggs to adhere to and develop. Artificial egg attachments are usually called fish nests. Natural materials for making fish nests can be used as long as they are soft, thin, and easy to spread in water and not easy to rot. Willow tree roots are commonly used in production. Because they grow by the river, willow tree roots are the most ideal for fish nests, and they can be used repeatedly after being made once. In recent years, fish nests made of 60-mesh silk made of artificial fibers are more durable. The fish nest materials are disinfected and tied into bundles of suitable sizes. Then they are tied to thin bamboo joints or tree chains. Common settings include suspension and parallel styles. Generally, the fish nest is arranged 1.2 meters away from the pond bank, or a well-shaped frame can be set up in the middle of the pond to suspend the fish nest, so that the fish nest sinks 15-20 cm underwater and makes the fish nest float. When managing, pay attention to the timely replacement of the fish nest according to the condition of the ovaries.