不同品系中华绒螯蟹土池生态育苗效果比较

Comparison on ecological breeding effects of Chinese mitten crab(Eriocheir sinensis)from different strains

为评估不同品系中华绒螯蟹(Eriocheir sinensis)的繁殖性能和育苗效果,分别采用中华绒螯蟹二龄早熟品系(雌体≥150 g,雄体≥210 g)、“长荡湖1号”A系(雌体≥200 g,雄体≥310 g)、“长荡湖1号”B系(雌体≥250 g,雄体≥360 g)及超大规格品系(雌体≥300 g,雄体≥400 g)作为亲本进行土池生态育苗试验,比较了各品系的抱卵蟹获得率、亲本孵化率、育苗期间的投饵量、幼体变态速度以及大眼幼体产量等指标。试验结果显示:(1)各品系越冬后的抱卵蟹获得率随着亲本规格的增大而明显降低,抱卵蟹成功孵化率随着亲本规格的增大同样呈降低趋势,但组间差异不明显(P>0.05)。(2)各品系投饵量在幼体培育期间呈现先增后减的变化趋势,其中,溞Ⅴ期最高,日投饵量约为75 g/m^(2);与之相反,幼体蜕皮周期在幼体培育过程中呈现出先降后增的变化趋势,溞Ⅲ-Ⅳ期蜕皮周期最短,仅为5~6 d。(3)除了个别产量异常的池塘外,各品系单蟹产苗量及饵料系数均随着亲本规格的增大而提高,且各品系大眼幼体淡化率差异较小,均在90%左右。结果表明,虽然大规格品系在单蟹产苗量方面存在一定优势,但因其抱卵蟹越冬后的回捕率及挂笼孵化率较低,整体育苗效果并无明显优势。今后仍需要通过遗传选育、亲本营养强化和优化亲本养殖管理等来提高抱卵蟹的成活率。

This study was aimed to evaluate the ecological breeding effects of Chinese mitten crab(Eriocheir sinen-sis)from different strains with different broodstock weights,i.e.early-maturing strain(dam weight≥150 g,sire weight≥210 g),‘Changdang Lake 1’Strain A(dam weight≥200 g,sire weight≥310 g),‘Changdang Lake 1’Strain B(dam weight≥250 g,sire weight≥360 g)and oversized size strain(dam weight≥300 g,sire weight≥400 g).The overwintering survival and hatching rate of broodstock as well as the feeding amount,metamorphosis rate and final yield of larvae were measured for breeding effects evaluation.The results showed that:(1)The overwintering survival and hatching rate of broodstock both reduced as broodstock size increasing.(2)The feed amount of larvae showed a‘low-high-low’trend during the breeding period,and the highest feeding amount was observed between ZoeaⅤand megalopa with 75 g/m^(2) per day.In contrast,the molting interval of zoea showed a‘high-low-high’trend during the breeding period,and the shortest interval was observed between ZoeaⅢandⅣwith only 5~6 days.(3)With the exception of some specific ponds,the yield and feed conversion ratio of larvae showed an increase trend with broodstock size increasing.There was little difference in post-desalination survival of megalopa among all strains with average survival of about 90%.In conclusion,although the broodstock with large size could produce more megalopa,the overwintering survival and hatching rate were relatively lower,these results indicated that genetic selection,nutrition enhancement and breeding management of broodstock should be optimized to improve the survival rate of broodstock in the future.