不同养殖模式及光照对凡纳滨对虾生长和水质的影响

利用室内水泥池4种不同养殖模式(虾单养或混养不同鱼类)和2种光照(自然光和弱光)对凡纳滨对虾生长、产量和水质的影响开展了研究。试验共设6个试验组,2个对照组,每个组别共设3个重复:自然光虾单养组、弱光组对虾单养、自然光虾鳅混养、弱光虾鳅混养、自然光虾鲢混养、弱光组虾鲢混养、自然光虾鳅鲢混养、弱光虾鳅鲢混养,养殖70d。测定试验前后试验池虾规格、总质量、存活率及饵料系数和鱼的规格、总质量。每隔15~20d测定水质指标。试验结果表明,单养组的虾自然光条件下规格显著大于其他组(P0.05),而弱光单养组的虾规格显著小于其他组(P0.05),其他组别差异不显著(P0.05)。饵料系数方面,单养组显著大于混养组(P0.05),存活率混养组显著高于单养组(P0.05),自然光组饵料系数和存活率显著高于弱光组(P0.05)。水质方面,养殖期间各组的硝态氮、亚硝态氮、氨氮呈稳步上升趋势,但亚硝态氮质量浓度,虾单养组和虾鳅混养组均显著高于虾鲢混养组和虾鳅鲢混养组(P0.05),自然光组显著低于弱光组(P0.05),氨氮,虾单养组显著高于其他组(P0.05),自然光组低于弱光组(P0.05)。试验结果显示,适当的光照是凡纳滨对虾生长的重要因素,泥鳅能大幅提高池塘经济效益节约成本,而鲢鳙鱼可有效地改善水质,当泥鳅以及鲢鳙鱼共同混养在虾池时,保证对虾池水质良好的同时,可提高对虾养殖的产量。

Impact of Culture Pattern and Light Intensity on Growth in Pacific White Leg Shrimp and on Water Quality

Pacific white leg shrimp (Litopenaeus vannamei) was reared in an indoor tank under conditions of monoculture at natural light (group A1 ) ,monoculture at low‐light (group A2 ) ,loach(Misgurnus an‐guillicaudatus)‐shrimp polyculture at natural light (group B1 ) ,loach‐shrimp polyculture at low‐light (group B2) ,silver carp(Hypophthalmichthys molitrix) bighead carp (Aristichthys nobilis) and shrimp polyculture at natural light (group C1 ) ,silver carp ,bighead carp ,and shrimp polyculture at low‐light (group C2 ) ,silver carp ,bighead carp ,shrimp and loach polyculture at natural light (group D1 ) ,and sil‐ver carp shrimp ,bighead carp ,and loach polyculture (group D2 ) at low‐light for 70 days .During the ex‐periment ,growth ,feed utilization and yield were measured and water quality including chemical oxygen demand (COD) ,and levels of NO3‐N ,NO2‐N ,NH3‐N ,total nitrogen (TN) ,total phosphorus (TP) and dissolved oxygen (DO) was determined in a 15 or 20 day interval .Results showed that the shrimp in mon‐oculture at natural light had significantly larger size than the shrimp in the other groups (P<0 .05) ,while the shrimp in monoculture under low‐light had significantly smaller size than the shrimp in the other groups (P<0 .05) ,without significant differences in the other groups .There were significantly higher food conversion ratio (FCR) and survival rate in the monoculture than those in the polyculture and signifi‐cantly higher FCR and survival rate under natural light that at low‐light (P<0 .05) .During the experi‐ment ,levels of NO3‐N ,NO2‐N ,and NH3‐N were steady elevated ,significantly higher nitrite level in group A and group B than those in group C and group D (P<0 .05) ,and significantly lower at natural light than at low‐light .There was significantly higher ammonia level in group A than those in the other groups (P<0 .05) .The findings show that proper lighting is an important factor in the growth of the shrimp ,and that loach can effectively improve the economic benefits of shrimp ponds .Silver carp and big‐head carp ,however ,can effectively improve the ecological benefits and yield of shrimp ponds .