| 1. Kaluga Huso dauricus belongs to Huso genus, Acipenseridae, Acipenseriformes, Chondrostei, Actinopterygii, Osteichthyes. There are only two species in genus Huso, which one is famous beluga Huso huso living in Black, Azov and Caspia Seas, that its caviar cost $10000/kg. The other one is Kaluga which is the largest freshwater fish in Amur river system reaching more than 5.6 m in length and more than 1000 kg in weight.Kaluga is endemic and rare species, its flesh is delicious and rich in nutrition. Its caviar is called as"black golden"and super dishes, costs RMB5000/kg at home. Kaluga price is high at RMB140/kg body, and RMB200/kg stomach, RMB 400/kg nerve cord. Kaluga skin is super leather materials.Kaluga is piscivorous and matured later, long reproductive cycle. Males population spawn for the first time at age 12～14 years, and females, at age 17–23. Spawning occurs in May–June at 12–21 ?C in Amur Rivers, in calm waters.As to the number of wild population, Kaluga is endangered species and its natural resource was decreased. This decline resulted from overfishing and environmental degradation such as: accumulation of pollutants in sediments, damming of rivers.2. Strict selection, transportation and maintenance of Kaluga bloodstocks were carried out from Amur down-midlle stream during May and June in 2001 and 2002. Male Kaluga breeder were not correspondent to HCG, HCG + carp PG, carp PG but LRH-A, LRH-A+ carp PG in effect and no different through inducing experiment, which show that LRH-A may be ideal hormone for inducing. In further investigation, through analysising of fertilization rate, hatchery ratio and larvae survival ratio, It was shown that wild-caught Kaluga broodstock is not rigid to inducing dose of LRH-A. It does almost not influence on fertilization, hatchery rate and larvae survival ratio that the dose vary between 2-12μg /kg BW, but dosage is 14-20μg /kg BW there is only an impact on the survival ratio of larvae kaluga. Through comparing the ratio of eggs harvested, the quality of eggs, fecundation rate (FR),hatchery ratio(HR) and viability of breeder kaluga came from"killed breeder", biopsy and"multi-stroke", It was found the effect of Biopsy similar with"killed breeder"populating in lot that only biopsy can save breeder 80% up and keep fertilization rate(FR) and incubation ratio reaching separately 88% and 82% while FR and HR are lower of"multi-stroke"but labor intention is high. Biopsy is the best way for eggs harvested. Fertilization methods were compared, which is shown that FR and HR are respectively 97% and 95% of"half-dry"more 10% than 90% and 85% of"dry methods"so that insemination of Kaluga should be"half-dry"."talcum powder"is the best ideal to removing stickiness from eggs through comprehensive analysis of FR and HR, the effect of removal stickiness , infection of Saprolegnia and labor intensity.It was found that favorable and optimal temperature is 16-24°C and 20°C respectively for incubation of Kaluga eggs fertilized through comparison of hatchery rate, the ratio of healthy larvae, infection rate of Saprolegnia by Yuschenko incubators improved.3. A preliminary study was carried out on the influence of different tank shape made from fiberglass and concrete on survival ratio of prelarvae Kaluga. It was discovered that survival ratio is more high of round tank than rectangular one,fiberglass tank than concrete one. While the experiment was designed according to the culture temperature of Kaluga prelarvae of 10 treatments, which were 8, 10, 12, 14, 16, 18, 20, 22, 24, 26°C. Results showed that favorable and optimal temperatures are 14-24℃ and 18-22℃respectively.4. The key of larvae Kaluga culture is how to transfer the larvae from the endo- nutrition (endogenous feeding phase or yolk-sac nutrition) to mix-nutrition, then from mix-nutrition to exogenous feeding, which is called as initial feeding. Initial feeding trials were supplied with fresh fish mince self-made, boiled egg yolk of chicken,salmon starter,alive rotifer, cladocera, tubifex, artemia nauplii. Being comparison of body length (BL), body weight (BW) growth and survival ratio, it was found that the best ideal starter is artemia nauplii and Cladocera, next is Tubifex and boiled egg yolk of chicken, inferor is salmon starter and fresh fish mince self-made.5. Weaning Kaluga is the key to rear Juvenile and table fish with pellet food. Trials were conducted of weaning juvenile Kaluga were initiated to feed tubifex, artemia nauplii, cladocera,which juvenile were feeding with pellet food (PF) , PF+ tubifex, PF+ artemia nauplii, PF+ cladocera, and PF dipped in tubifex ,artemia nauplii,cladocera juice. Results show that Juvenile Kaluga were weaned successfully initiated to feed artemia nauplii and cladocera in shorter time, higher weaning percent, higher survival ratio and growth rate than tubifex, that with pellet food dipped in juice of tubifex, artemia nauplii, cladocera in shorter time, higher weaning percent, higher survival ratio and growth rate than first with formulated food then tubifex, artemia nauplii, cladocera, therefore it is effective that Kaluga juvenile is weaned by pellet food dipped in cladocera and artemia nauplii juice.6. Trials were designed thee treatments with repetition in concrete tanks with flowing water, net cages and earth ponds. Results indicate farming effect in order is concrete tanks with flowing water, net cages and earth ponds, that body weight reach at. 45.96kg, 44.87kg and 37.9kg respectively, and that food coefficient is as following: 1.0, 1.2, 1.4 in five years later. 7. A preliminary study on acclimation of Kaluga sturgeon, Amur sturgeon and the hybrid to saline water.A preliminary study has been carried out on the acclimation of Kaluga sturgeon (Huso dauricus), Amur sturgeon (Acipenser schrenckii) and the hybrid (H.dauricus♀×A.schrenckii♂) to saline water by increasing salinity continuously and continually. The cumulative mortality are 23.3%, 65% and 33.3%, and 3.3%, 6.7% and 5.0% separately of Kaluga sturgeon, Amur sturgeon and the hybrid sturgeon in continuous Increasing salinity experiments and in continual increasing experiments until the salinity reaches at 30‰at last. The possibility of sea farming and the principle of acclimation were discussed.8. A preliminary study on juvenile growth performance of Kaluga (Huso dauricus ) hybrid under artificial farming conditions. Under artificial farming conditions, a preliminary study was carried out on juvenile growth characteristics of Kaluga hybrid {[(Kaluga♀×Amur sturgeon♂) natural hybrid♀]×Kaluga♂}. The results showed that the juveniles reached a mean body weight (MBW) of 437.36g and a mean body total length (BTL) of 48.76 cm after 75 days rearing from a mean body weight of 145.83g and a mean body total length 33.32 cm when they were 139 days old. We found that there is a linear relationship between total length and days old in the form of L=0.2195t+3.2969, R2=0.9594, and there is power functional relationship Wgc=17.216e0.0516t, R2=0.956, between body weight and days old, and the total length-weight relationship is WwL=0.0056L2.8929, R2=0.9982. The function is close to 3, which shows that the weight is related to the cube of the length and the growth is isometric of hybrid juveniles. The body total length increased at 2.06mm on average of hybrid juveniles and instantaneous growth ratio was 0.0763, and the body weight gained at 3.8871g/d on average and instantaneous growth ratio is 0.2197. |
PDF Full Text Request