At first glance, it is best to choose ancestral fish before the Spring Festival (ie when lots of adult fish are harvested). At this time, the choice of broodstock due to reduced food intake of fish, activities are slow, tight scales, not easy to hurt.
Secondly, the age of sexual maturity of farmed fish is generally: squid 3-4 years old, squid, grass carp 4 to 5 years old, oysters, oysters, oysters more than 2 years of age, herring are more than 6 years of age.
Thirdly, we must choose a healthy physique, complete scales and fins, no disease, and no traumatic fish as broodstock.
The more you look at the weight of the broodstock, the greater the amount of ovulation or storage. General broodstock weight selection criteria are: squid 3 to 4 kg, 8 kg squid, grass carp 7 kg, scorpion, scorpion, scorpion more than 1 kg.
Fifth, if the kinship is mated with the offspring of the offspring of the same broodstock, its offspring will grow slowly, become ill, and reduce its yield. Therefore, females and males used for breeding broodstock should come from different places, and the distance between the two places should be as far away as possible.
Sixth, when the gonadal development level is selected, the development of the gonad (ovary or testis) reaches the third stage. Two methods can be used to observe, first from the outside, there are obvious ovary bulges on both sides of the abdomen; second, the autotrophic fish can choose several representative anatomy of the tail, you can see the ovary grow on both sides of the abdominal cavity, showing a grayish gray. In the winter, the ovaries are more than 2 cm wide and 15 cm long.
Seven to see the proportion of male and female fish to be appropriate, generally 1:1, male fish can not be too much.
In addition, some female fish older than 2 years old or male fish can be reserved in the adult fish pond in advance and reserved as broodstock, and male and female fish can be allocated accordingly.
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