流水槽和池塘两种养殖模式下大口黑鲈存活率、生长和性腺成熟的比较研究

通过比较大口黑鲈(Micropterus salmoides)在流水槽-池塘接力养殖和池塘养殖两种模式中的存活率、生长、性腺成熟、饵料系数的差异,以探索大口黑鲈流水槽-池塘接力养殖新模式的可行性。在8月初将大口黑鲈鱼苗(初始平均体重为23.933 g)分别放养于池塘和水槽中养殖,并于次年4月份将流水槽养殖的大口黑鲈转入池塘接力养殖至6月份,定期检测大口黑鲈生长、性腺成熟系数、饵料系数等。结果表明:流水槽养殖大口黑鲈存活率高于池塘养殖组,流水槽养殖组水质指标(溶解氧、氨氮、亚硝酸盐)均优于池塘养殖组;在养殖前期,池塘组保持了生长优势,11月份开始生长减缓,每隔2个月体重存在显著差异,而流水槽养殖组鲈鱼体重在各月份之间差异显著;在各个采样时间点,池塘养殖组鲈鱼体重离散系数高于流水槽养殖组,而水槽组中离散系数随鲈鱼生长呈现波动起伏;3-4月份是大口黑鲈性腺发育期,在此阶段流水槽中鲈鱼的性腺成熟系数为3-6月中的最高;在整个养殖周期内3-4月份日增量最低。综上所述,在养殖前期,池塘组鲈鱼的生长略占优势,但在存活率、水质、饵料系数、性腺发育等方面劣于流水槽组;养殖后期,流水槽组存在饵料系数升高、个体差异增大、生长速率减缓等问题,从生长和经济成本的考虑转入池塘养殖更有利,因此流水槽-池塘接力养殖大口黑鲈具有一定的可行性,4月份是将大口黑鲈从流水槽转移至池塘进行接力养殖的适宜时期。

Comparison research on survival,growth and gonad maturity coefficient of Micropterus salmoides reared in two culture modes

The new mode of Micropterus salmoides in-pond raceway system(IPRS)-pond relay farming was explored to compare the growth advantages of bass in different breeding modes in different periods.Largemouth bass(initial average body weight of 23.933 g)were stocked in the pond and IPRS in August,respectively,and then transferred the bass of IPRS to the pond in April for further culture until June.We checked the body weight,daily gain weight,gonad maturity coefficient and feed coefficient of largemouth bass in each stage on time.The results showed that the survival rate of the bass in IPRS was 81%higher than that in the pond.The basic water quality indexes dissolved oxygen,ammonia nitrogen and nitrite in the IPRS were all better than those in the pond group.The growth advantage of the pond group was maintained in the early growth stage,and the rate of growth began to slow down in November.There was a significant difference between the body weight in the pond every two months(P<0.05),while in the IPRS always had a significant difference every month(P<0.05).At each sampling time point,the body weight dispersion coefficient of the pond group was higher than that of the IPRS group.At this stage,the gonadal maturation coefficient of the bass in the IPRS was the highest from March to June.The daily increment of March-April was the lowest in the whole breeding cycle.In conclusion,the growth of the bass in the pond group had a slight advantage in the early stage.However,the survival rate,water quality,feed coefficient and gonadal development were worse than those in the IPRS group.In the later stage of growth,the IPRS group also had some problems,such as higher feed coefficient,more significant individual difference and slower growth rate,so it was more favourable to transfer to the pond from the consideration of growth and economic.Therefore,it is feasible to breed largemouth bass in the way of IPRS-pond relay,and April is the suitable period to transfer bass from IPRS to pond.