Light yellow croaker (nibea coibor) the common name white Chennai, gold salamander, belonging to Perciformes, Sciaenidae, yellow croaker is. The fish meat is tender, taste the unique, delicious taste, the swim bladder is a valuable tonic in Chinese medicine. Light of croaker fish are warm water, temperature range of 8 ~ 33 ℃, the optimum growth temperature was 24 ~ 29 ℃, spawning water temperature 24 ~ 28 ℃, Ⅱ old age of sexual maturity, growth and suitable salinity range of 10 40. To investigate the light Nibea artificial propagation and breeding techniques, the author in 2002 and 2003 on the artificial light yellow croaker breeding techniques were tested, are presented below.
First, broodstock _select_ion and breeding
Second, artificial spawning
The water temperature stable at above 25 ℃, specific gravity 1.018 ~ 1.024 in the environmental conditions, namely, intramuscular injection of oxytocin. Female injection hcg400 ~ 500 IU / kg of fish off and lrh-a6 ~ 8 mg / kg of fish, males injected hcg300 ~ 350 IU / kg of fish, the general effect of time of hormone injection of 36 to 40 hours, broodstock natural spawning can be fertilized.
Third, the fertilized egg hatching
Fertilized eggs with water method (in the cement pool in the eggs) to collect, or silk mesh with 100 mesh screen (in the cage eggs) collected, washed to remove impurities and dead eggs sink to the bottom, the use of 15 to 20 grams / cubic meter pvp iodine soak 5 to 8 minutes after the move to an outdoor cement tank hatch. After incubation water sedimentation, filtration, disinfection, water accounting for 1.018 ~ 1.024, ph value of 8.0 ~ 8.3, temperature 24 ~ 28 ℃, generally 18 to 22 hours after hatching.
Fourth, larval rearing
After the larvae hatch into cement pond cultivation of Chlorella in advance in cement pool in the access (the color light green), larval rearing water temperature was 24 ~ 28 ℃, specific gravity 1.016 ~ 1.022, ph is 8.0 ~ 8.3, light < 2000 lux, dissolved oxygen> 5 mg / l, ammonia <0.3 mg / l, hydrostatic micro-inflatable, water fresh, daily pollutant 1 or 2 times, changing water 1 / 3, the general development by 44 to 55 hours after the opening , after opening the larvae fed rotifers as a weaning food, water rotifer density control in 5 to 8 / ml range. Rotifers to the high concentration of the chlorella cultivating enhanced by 5 to 8 days of cultivation, the larvae can grow to 0.6 to 0.8 cm, then you can nurture into earthen ponds.
Fifth, standard coarse earthen ponds
1. Qingtang _select_ 2 to 5 acres of cultivation, the pool depth of 1.2 to 1.8 meters, the bottom flat, muddy sand rectangular earthen ponds for breeding ponds. Tea cake (20 to 30 grams / cubic meter), and bleaching powder (60 ~ 80 grams / cubic meter) clear pond than wild, the first water of 0.6 to 0.7 m, organic fertilizer (such as chicken manure, etc.) 15 kg / mu the same time, Shi photosynthetic bacteria (the amount of fertilizer by product description), by 5 to 7 days of cultivation, the pool has large population of food organisms (rotifers, copepods, nauplii the total is greater than 2000 / L).
VI Summary
1. Light yellow croaker Ⅱ age of sexual maturity age, but the _select_ion of broodstock spawning age Ⅱ, less effective, less eggs, more than the best choice Ⅲ broodstock age, light yellow croaker to improve the spawning rate and fertilization rates, it is necessary during the breeding season the first two months of intensive cultivation of broodstock, fed fresh or chilled round scad, sardines, squid and other bait, and bait in the amount of vitamin e and vitamin b; Control light (2000 lux in the following), and other related environmental factors; broodstock gonadal development according to the situation, each injection lrh-a half months on a regular basis for artificial ripening hormone.
2. Indoor nursery pond environment has become more stable, but with the growth of fish, requires a lot of food organisms, a large number of concrete ponds is very difficult to supply food organisms; and outdoor concrete ponds can be substantial reproduction through the method of fertilization food organisms to meet the fry growth and development needs. Therefore recommends that: the artificial light yellow croaker larvae breeding can be pre-high-density cultivation in indoor concrete ponds, post-larvae after the move to outdoor earthen pond cultivation method of combining.
3. Through direct access to the nursery to add beneficial bacteria in water (such as photosynthetic bacteria, em monocytogenes) and Chlorella way to adjust the composition of biological communities breeding pools, thus effectively maintain a good environment for breeding of water conditions, reduce diseases, improve the survival rate of fry. |