图们江细鳞鲑人工繁殖技术研究

Artificial Breeding of Brachymystax lenok in the Tumen River

为研究细鳞鲑(Brachymystax lenok)人工繁殖技术,采捕图们江野生细鳞鲑幼鱼,经人工培育至性成熟,连续4年进行人工繁殖。繁殖水温6~13℃,亲鱼4+龄以上;采用2.5μg LHRH-A2+2.5 mg DOM一次性催产,可以达到预期催产效果。催产率、发眼率、孵化率、亲鱼产后成活率分别达到90%、95%、89%、95%。通过分析80尾卵巢发育至Ⅴ期、平均体重(1 165.11±500.30)g细鳞鲑样本,其绝对怀卵量为(3 195.61±1 430.04)粒,相对怀卵量(2.72±0.17)粒/g,成熟系数(13.54±1.14)%。绝对怀卵量(F)与年龄和体重(W)密切相关,与体重呈线性关系,拟合关系式为F=2.843W-120.43,R2=0.9754。减少检查次数、采用药物麻醉、产后药物处理可以避免造成亲鱼受伤,降低应激反应,提高亲鱼产后成活率。

Brachymystax lenok is an important cold water fish species inhabiting northeast and northwest China. In recent years,their populations and range have decreased due to environmental change and anthropogenic activities and artificial breeding of B. lenok is now necessary. Our research group carried out a four-year study on artificial breeding of the species from 2012 to 2015 and developed an integrated system for artificial breeding. The study is significant for large-scale seedling production and conservation of B. lenok. Wild juvenile B. lenok were collected from the Tumen River basin and reached sexual maturity（ male： 3＋years,420-630 g; female： 4＋years,438-745 g） after 2-3-years. Parent fish were maintained in a culture pond with water depth of 60-70 cm,water flow of 15 m3/min,pH 6. 8-7. 1 and DO of 5 mg/L. Healthy,mature individuals were selected and artificial spawning was induced by injecting 2. 5 μg LHRH-A2＋ 2. 5 mg DOM at a water temperature of 6-13℃. Fertilized eggs were then collected and incubated indoors under low lighting. During incubation,the water flow was maintained at3-5 L/min and water temperature was measured every morning and evening for calculation of average and accumulated temperature. Eyed eggs and newly hatched larvae were counted to calculate the percentage of eyed eggs and hatching rate and dead eggs and seedlings were removed. Results improved each year and,in 2015,the spawning rate,eyed egg rate,hatching rate and survival rate of parents after spawning were,respectively,90%,95%,89% and 95%. The reproductive parameters of 80 females whose ovaries grew to stage V were analyzed and the average body weight was（ 1 165. 11 ± 500. 30） g,absolute fecundity was（ 3 195. 61 ± 1 430. 04） eggs,relative fecundity was（ 2. 72 ± 0. 17） eggs per gram and the maturity coefficient was（ 13. 54 ± 1. 14） %. Absolute fecundity（ F） was closely related to age and body weight（ W） and F was expressed as a function of W by the linear equation,F = 2. 843W-120. 43,R2= 0. 9754. Taking measures,such as reducing check frequency of parent fish,use of anesthesia during artificial induced spawning and drug treatment of parent fish after spawning can reduce injuries and stress,and improve parent survival rate. The size of parent fish is increased by feeding fresh,live food in winter to ensure nutrient needs are met and maintaining a stabile hatching environment improves the spawning rate,egg quality and hatching rate of B. lenok.