哲罗鱼人工育苗技术研究

Artificial propagation of huchen,Hucho taimen Pallas

采捕野生乌苏里江哲罗鱼（Hucho taimen Pallas）幼鱼，在流水池塘中培育至性腺成熟，进行人工繁殖和育苗技术的研究。结果表明：注射催产激素HCG、S-GnRH—A和DOM的混合制剂可促使成熟的亲鱼排卵，（9±2）℃水温药物的效应时间在8～11d。哲罗鱼的受精卵，为圆形、淡黄色，卵膜较软，无粘性。7^＋～9^＋龄鱼的卵径为4．20～5．56mm[平均（4．98±0．33）mm]；吸水膨胀后的卵径为4．32～5．76mm[平均（5．20±0．38）mm]，增大约0．2mm。6～12kg的雌性亲鱼绝对产卵量为4500～14000粒／尾，相对产卵量1000～1200ind／kg。哲罗鱼人工繁育的催产率、发眼率和仔鱼上浮率平均为87．5％、83．5％和86．4％。从卵受精到破膜需28～31d[平均（29．3±1．3）d]，完全出苗需38～41d[平均（38．5±1．0）d]，仔鱼上浮需56～58d[平均（57．1±0．9）d]。鱼苗驯化依次投喂水蚤→水蚤、水丝蚓→水丝蚓→水丝蚓、软颗粒饲料→软颗粒饲料→软颗粒饲料、硬颗粒饲料→硬颗粒饲料，可从动物性饵料转化为人工配合颗粒饲料喂养。人工养殖条件下，仔鱼体长与日龄的回归方程为L=1．9623e^0.0219t，（序=0．9507，n=30），稚鱼体长与日龄的回归方程为L=2．6877e^0.0119t，（R^2=0．9943，n=30），1龄鱼的平均体长为（16．2±0．93）cm，体重为（28．45±2．98）g。

The juveniles of wild Hucho taimen Pallas were caught and reared to adult in a pond with flowing water, and propagation and seed culture were carried out. The results showed that the Hucho taimen could be artificially induced to spawn time after time during the period of their reproduction seasons by injecting the hormone mixture which was composed of HCG, S-GnRH-A and DOM. It＇ s about 8 - 11 days for the fish to spawn after injecting at water temperature （9 ＋-2） ℃. The eggs are round, no sticky, light yellow, and with a soft ovum membrane, and the eggs which were got from the 7 ^＋ - 9 ^＋ years old brood stocks had a diameter of 4.20-5.56 mm, and the average value was （4.98 ±0.33） mm; after absorbing water, diameter becomes 4.32 -5.76 mm and the average value becomes （5.20 ± 0.38） mm. The absolute fecundity is 4 500 - 14 000 eggs per fish, the relative fecundity is 1 000 - 1 200 eggs per kg. The average value of artificial inducing ratio, eyed-eggs percentage and larva floating ratio were 87.5%, 83.5% and 86.4%, respectively. The developmental stages from fertilized egg to becoming fry with membrane, to getting out of the membrane completely and to floating larva need 28 - 31 d [ average （29.3 ＋- 1.3 ） d ], 38 - 41 d [ average （38.5 ± 1.0） d ] and 56 - 58 d [ average （57.1 ± 0.9） d ], respectively. Using the acclimation method of gradual transition （ daphnia→ daphnia, limnodrilus →limnodrilus → limnodrilus, soft granular food → soft granular food→ soft granular food, hard granular food→hard granular food）, the fish fry can be weaned to artificial dry foods by gradually reducing the animal feed. Under the artificial culture conditions, the relationship between total length and day age of larva is L = 1. 9623e^0.0219t, （R^2 =0. 9507, n =30） , and the relationship between total length and day age of juvenile is L =2. 6877e^0.0119t, （R^2 =0. 9943, n =30）, and after the first year average body length is （16.2 ±0.93） cm, the average body weight is （28.45 ±2.98） g.