Plecoglossus altivelis artificial reproduction method

Abstract

The invention discloses a smelt artificial propagation method. From the early June, the fodder containing more fish meal protein is used for the feeding of female parent fishes. While from the middle of September, the female parent fishes are fed on the fodder containing spirulina powder and aluzyme. After the parent fishes enter the gonad mature period, the better mature female parent fishes are selected and cultivated after the estrualization, and the sexually mature male parent fishes are selected and cultivated after the estrualization. After the cultivated parent fishes reach more than 60 % gonad maturity, the water temperature of a decorporation pool is dropped continuously for 2 days with the decline of 2 degree each day. Afterwards the constant temperature is kept for 4 to 6 days. During the ovulatory period of parent fish, the ovums and the sperms are artificially collected every two days. The dry artificial insemination method is used to obtain a germ cell, and the germ cell is put in a hatchery pond for breeding. With the invention, the smelt sverage absolute fecundity and the fertility rate can be enhanced, and a great number of fry can be obtained in each breeding. The scale of artificial propagation is increased, and the labour intensity of the artificial propagation is reduced. Thus a foundation for the large scale artificial culture of smelt is established.

Description

technical field [0001] The invention relates to artificial breeding technology of fish, in particular to an artificial breeding method of sweetfish. Background technique [0002] Sweetfish (Pleccoglossus altivelis Temminck et Sohlegel) belongs to the sweetfish family and is a rare and valuable freshwater fish. At present, the purchase price per kilogram of sweetfish is as high as 80 yuan in China, as high as 400 Taiwan dollars in Taiwan, and as high as 1,500-2,000 yen in Japan. Therefore, the development of industrialized artificial breeding of sweetfish has broad prospects. At present, due to the limited number of artificial breeding of sweetfish fry, the scale of artificially cultured sweetfish is very small, and the output of sweetfish is also small. [0003] Ayu is a yearly mature fish. According to the research, it is found that the female ayu usually begins the ovarian proliferation period in the first ten days of June, that is, the oogonia undergoes mitosis, so that ...

AI Technical Summary

Problems solved by technology

The maturation time of gonads of different female ayuts is different. The number of eggs that artificially bred female ayutth can lay at the same time is limited, and the amount of eggs in each breeding is small; Divide into three batches, and the interval between ovulation in each batch is 13-15 days. The average absolute egg size of sexually mature female ayu is about 30,000 eggs, and the average amount of eggs released from the ovary to the ovarian cavity is only 10,000 eggs each time. Left and right, fewer eggs are produced from the ovarian cavity to the outside of the body; eggs with poor quality are difficult to fertilize, and eggs that have been in the ovarian cavity for more than 48 hours are also difficult to fertilize when they are produced outside the body. Even if some of them can be fertilized, it is difficult Difficult to hatch normally

Therefore, the problem that restricts the artificial reproduction of sweetfish is: there are few female sweetfish that can ovulate at the same time, so the number of eggs for each artificial breeding is also small, and it is difficult to collect more than one million eggs at the same time; The average absolute fecundity of sweetfish is low, so that the number of eggs that can be collected is small; the quality of the eggs makes the fertilization rate of artificial reproduction only reach 70%, so the number of fertilized eggs obtained by artificial insemination is even less , poor quality eggs lead to poor quality of fertilized eggs and lower hatchability

Therefore, only small batches of artificially propagated sweetfish fry are currently available, and the number of fry obtained by each breeding is small, and the benefit of artificial propagation is low. To obtain more fry, it will be multiplied multiple times, which increases the cost of reproduction and labor intensity.