长江鲟子三代繁育技术研究

经过长达20余年的人工保种,长江鲟Acipenser dabryanus子三代苗种在2018年首次成功获得。运用B超鉴定性腺发育期技术,从6~8龄子二代长江鲟亲鱼群体中挑选出成熟雌雄亲鱼各6尾,雄鱼平均体质量(17.02±4.97) kg,雌鱼平均体质量(20.57±3.23) kg,在水温19.0~20.0℃下,实施人工催产,成功催产雄鱼5尾,雌鱼2尾,获卵约9万粒,平均卵径(2.65±0.19) mm,受精率87.53%,孵化率76.14%,共孵出子三代长江鲟仔鱼约6万尾,获开口期仔鱼约3万尾;子三代长江鲟初孵仔鱼体长(0.91±0.06) cm,体质量(0.021±0.003) g。仔鱼体质量呈指数增长,增长方程式为W=0.108 1e^0.333 2t(R^2=0.931 8,n=105,P<0.01);体长呈直线增长,增长方程式为L=1.087 8t-1.746 2(R^2=0.986 1,n=105,P<0.05);体质量与体长之间相关关系为W=0.040 6L^2.308 9(R^2=0.991 1,n=105,P<0.01)。长江鲟子三代苗种生长性能与子一代和子二代的差异无统计学意义。长江鲟子三代繁育成功是长江鲟迁地保护的重大突破,预示着长江鲟可持续人工群体建设和人工保种成功,将为今后长江鲟自然种群复壮及未来的养护利用奠定基础。

Technologies for Reproduction of the Third Generation of Acipenser dabryanus in Captive

Through more than 20 years efforts in saving the critically endangered Dabry's sturgeon(Acipenser dabryanus)in captive,the third generation of this sturgeon have been successfully reproduced in 2018 at the first time.Six male and female parents A.dabryanus of the second generation with an average body mass of(17.02±4.97)kg,and(20.57±3.23)kg,respectively,were selected by B-ultrasonic technique which can identify the development stage of gonad,from a propagation group with an age of 6-8 years old.The artificial spawning was conducted when the water temperature reached to 19-20℃,5 male and 2 female fish were induced successfully.A total of 9 × 10^4 eggs with an average diameter of(2.65±0.19)mm were obtained.The fertilized rate was 87.53%,and the hatching rate was 76.14%,about 6 × 10^4 hatching-out larvae were finally produced with a body length of(0.91±0.06)cm and a body mass of(0.021±0.003)g,and 3 × 10^4 larvae were remained after initial-feeding.The body mass of the larvae increased exponentially shown as W=0.1081e^0.3332t (R^2=0.9318,n=105,P<0.01),and the body length of the larvae increased linearly shown as L=1.0878t-1.7462(R^2=0.9861,n=105,P<0.05),and the correlation between body mass and body length was shown as W=0.0406 L^2.3089(R^2=0.9911,n=105,P<0.01).The success of breeding the third generation is a big breakthrough in the ex situ conservation of A.dabryanus,it indicates that the continuable artificial population of A.dabryanus was established and the preservation of A.dabryanus was succeesfully,and it will contribute to further restoration and utilization of nature resource.