暗纹东方鲀立体种养模式和单养模式的水质变化及养殖能效比较

Comparative analysis of water quality changes and cultural efficiencies between multistory culture model and traditional monoculture model of obscure puffer (Takifugu obscurus)

摘要:

为解决暗纹东方鲀（Takifugu obscurus）单一品种的池塘养殖瓶颈问题，开发和建立多物种、多营养层次的生态立体种养池塘生态系统，于2019年研究了暗纹东方鲀（1.2万尾/hm²）、凡纳滨对虾（Litopeneaus vannamei）（24万尾/hm²）和蕹菜（Ipomoea aquatica Forsk）的立体种养模式与暗纹东方鲀传统单养模式（1.5万尾/hm²）的水质变化及养殖能效差异。结果显示：暗纹东方鲀立体种养模式和传统单养模式池塘水体的pH、总氨氮（TAN）、亚硝酸氮（NO₂-N）和硝酸氮（NO₃-N）等水质指标数值保持在较理想范围内，这些指标中除了7月8日立体种养模式的NO₃-N显著低于传统单养模式外，其他在两种模式之间无显著性差异。立体种养模式的叶绿素a质量浓度明显低于传统单养模式。两种模式的总氮均值分别为1.38~3.96 mg/L和1.04~3.20 mg/L，养殖中后期（7月24日-10月11日），立体种养模式的总氮高于传统单养模式。立体种养模式的总磷（TP）变化随养殖时间呈现缓慢平稳上升趋势（0.26~0.42 mg/L）；而传统单养模式总磷质量浓度在养殖中期较高、前期后期较低。除了5月6日监测化学耗氧量（COD）质量浓度相对较高外，其他监测的时间点两种养殖模式的COD质量浓度相对较稳定，均值为6.79~10.24 mg/L和6.83~9.15 mg/L，两模式间均无显著性差异。固体总悬浮物（TSS）质量浓度总体较高，特别是6月13日的水源、7月24日及8月19日的传统单养模式和9月15日的立体种养模式的TSS质量浓度均超过150 mg/L。各监测时间点的TSS质量浓度在两种养殖模式之间无显著性差异。两种模式暗纹东方鲀的养殖有助于池塘水体的pH、TAN、NO₂-N和NO₃-N的净化，对水体中总磷（TP）和TSS的影响不明显，但会造成水体中总氮（TN）和COD质量浓度升高。立体种养模式和传统单养模式的暗纹东方鲀生长没有显著性差异，放养密度（1.2万~1.5万尾/hm²）没有造成暗纹东方鲀生长的空间胁迫。除了立体种养模式的暗纹东方鲀的单位产量（3 426.0 kg/hm²）显著低于传统单养模式（4 055.7 kg/hm²）外，立体种养和传统单养模式的暗纹东方鲀的出池规格（293.30 g/尾和297.53 g/尾）、成活率（97.38%和94.60%）以及饵料系数（2.83和2.91）均无显著性差异。立体种养模式下套养的凡纳滨对虾生长性能良好：产量为3 056.6 kg/hm²，规格为22.48 g/尾，存活率为78.17%，饲料系数为0.68，鱼虾叠加后的饲料系数总体为1.39。相对于暗纹东方鲀传统单养模式，立体种养模式在养殖尾水排放减少11.1%的前提下，每公顷增效87 675元，每667 m²增效5 845元。

Abstract:

In order to develop and set up ecological multistory culture pond ecosystem of obscure puffer (Takifugu obscurus), Litopeneaus vannamei, and Ipomoea aquatica Forsk, the differences of the water quality changes and the cultural efficiencies between multistory culture model and traditional monoculture model of obscure puffer were studied. The results showed that the values of water quality parameters of pH, TAN, NO₂-N, and NO₃-N in the pond of multistory culture model and traditional monoculture model of obscure puffer maintained within the ideal range. In these parameters, except that the NO₃-N(0.110 mg/L)of the multistory culture model on July 8 was significantly lower than the NO₃-N(0.630 mg/L)of the traditional monoculture model, there was no significant difference in other parameters between the two models. The Chl a of the multistory culture model was significantly lower than that of the traditional monoculture model. The scopes of the average total nitrogen (TN) in two models were 1.38-3.96 mg/L and 1.04-3.20 mg/L, respectively, in the middle and later periods of the culture (from July 24 to October 11), the TN of the multistory culture model was significantly higher than that of the traditional monoculture model. During the cultural time, the total phosphorus (TP) of the multistory culture model showed a trend of slow rising steadily (0.26-0.42 mg/L), while the total phosphorus (TP) of the traditional monoculture model showed a trend of high middle (0.50-0.56 mg/L) and low on both sides (0.18-0.37 mg/L). Except that the COD value of two models on May 6 is relatively high (the multistory culture model 14.05 mg/L and the traditional monoculture model 15.03 mg/L, respectively), in the other monitoring points in time, COD values are relatively stable, the mean ranges were 6.79-10.24 mg/L and 6.83-9.15 mg/L, respectively, and there was no significant difference between the two models. Overall, the TSS (total suspended solid) value was higher, especially source water on June 13(154.20 mg/L), the traditional monoculture model on 24 July and August 19(186.60 mg/L and 181.53 mg/L, respectively), and the multistory culture model on September 15(189.87 mg/L), these TSS values were more than 150 mg/L. In each monitoring point in time, there was no significant difference in the TSS between the two models. Obscure puffer culture was advantageous to the purification of pH, TAN, NO₂-N, and NO₃-N in pond water of the two models, and there was no obvious influence on the TP and TSS in pond water, while, it caused the increase of total nitrogen (TN) and COD in pond water. There was no significant difference in growth of obscure puffer between the multistory culture model and the traditional monoculture model, the stocking density (12 000-15 000 ind/hm²) of the two models did not cause space stress of obscure puffer growth. Except that the obscure puffer unit yield (3 426.0 kg/hm²) of the multistory culture model was significantly lower than that of the traditional monoculture model (4 055.7 kg/hm²), there was no significant difference in out-pond specification (293.30 g/ind and 297.53 g/ind, respectively), survival rate (97.38% and 94.60%, respectively), and food coefficient (2.83 and 2.91, respectively) between the two models. Litopeneaus vannamei of polyculture in the multistory culture model showed good growth performance:the unit yield of Litopeneaus vannamei was 3 056.6 kg/hm², the out-pond specification was 22.48 g/ind, the survival rate was 78.17%, and the food coefficient 0.68, and the overall superimposed feed coefficient of fish and shrimp was 1.39. Compared with the obscure puffer traditional single model, under the condition of 11.1% reduction in aquaculture tail water discharge, the benefit of the multistory culture model increased by 87 675 yuan per ha.