Azhar Muhammad Hanif, Memiş Devrim
Department of Aquaculture and Fish Diseases, Institute of Graduate Studies in Sciences, Istanbul, Turkey.
Department of Aquaculture, Faculty of Fisheries and Marine, Universitas Airlangga, Surabaya, Indonesia.
Water Environ Res. 2025 Feb;97(2):e70046. doi: 10.1002/wer.70046.
Increasing nutrient concentrations in fish culture systems over time can reduce water quality. However, the nutrient increase can be remediated by pairing organisms at lower trophic levels with a mechanical filtration system to improve nutrient removal efficiency and water quality for fish culture. This research uses the RAS system to determine the performance of integrating living organisms as biofilters in rearing juvenile rainbow trout (Oncorhynchus mykiss) for 56 days. Duckweed (Lemna minor) was added to replicate tanks at three treatment levels: T1 (100 g wet weight and 20% area coverage), T2 (200 g wet weight and 40% area coverage), and T3 (300g wet weight and 60% area coverage). The duckweed in each treatment tank was supplemented with 20 freshwater mussels (Anodonta cygnea) with an average body weight of 56 ± 1.0 g. Physical and chemical water quality parameters were measured in fish tanks and all ponds in the RAS system. Fish from the rearing tanks were weighed every two weeks. Duckweed biomass was measured weekly; the mussels were weighed at the beginning and end of the study, and the mussels were measured at the beginning and end of the rearing period. The fish was partially harvested every two weeks to maintain constant fish biomass. Using duckweed (L. minor) with different biomass weights and areal coverage, coupled with the freshwater mussels (A. cygnea) as living biofilters, had a significant effect (P < 0.05) on water quality parameters. Ammonium (NH), nitrite (NO), and nitrate (NO) concentrations decreased throughout the study. During the study period, juvenile trout experienced growth with an SGR of 2.62-2.72%/gram with a survival rate of 100%. Partial harvesting during the rearing period positively impacted the average body weight of fish growth and duckweed biomass. The best duckweed growth performance was found in treatment T1 (cover area 20% with wet weight 100 g) with a productivity of 9.4 (g/m/day). PRACTITIONER POINTS: Twenty percent duckweed coverage with freshwater mussels achieves optimal nutrient removal in RAS systems, improving water quality efficiently and growth better than other treatments. Combined biofilters (duckweed-mussel) and filtration units reduce operational costs while maintaining high fish survival rates in RAS systems. Integration of living biofilters provides sustainable water treatment without chemical additives, suitable for small-scale aquaculture operations.
随着时间的推移，鱼类养殖系统中营养物质浓度的增加会降低水质。然而，通过将低营养级生物与机械过滤系统相结合，可以修复营养物质的增加，以提高营养物质去除效率和鱼类养殖的水质。本研究使用循环水养殖系统（RAS）来确定在养殖虹鳟幼鱼（Oncorhynchus mykiss）56天的过程中，将活体生物作为生物过滤器的性能。浮萍（Lemna minor）被添加到三个处理水平的重复水箱中：T1（100克湿重和20%的面积覆盖率）、T2（200克湿重和40%的面积覆盖率）和T3（300克湿重和60%的面积覆盖率）。每个处理水箱中的浮萍都补充了20只淡水贻贝（Anodonta cygnea），平均体重为56±1.0克。对RAS系统中的鱼缸和所有池塘中的物理和化学水质参数进行了测量。每两周对养殖水箱中的鱼进行称重。每周测量浮萍生物量；在研究开始和结束时对贻贝进行称重，并在养殖期开始和结束时对贻贝进行测量。每两周对鱼进行部分收获，以保持鱼的生物量恒定。使用不同生物量重量和面积覆盖率的浮萍（L. minor），并结合淡水贻贝（A. cygnea）作为活体生物过滤器，对水质参数有显著影响（P<0.05）。在整个研究过程中，铵（NH）、亚硝酸盐（NO）和硝酸盐（NO）浓度均下降。在研究期间，虹鳟幼鱼生长，特定生长率（SGR）为2.62-2.72%/克，存活率为100%。养殖期间的部分收获对鱼生长的平均体重和浮萍生物量产生了积极影响。在处理T1（覆盖面积20%，湿重100克）中发现浮萍生长性能最佳，生产力为9.4（克/平方米/天）从业者要点：浮萍覆盖率为20%并搭配淡水贻贝，在RAS系统中实现了最佳的营养物质去除，比其他处理更有效地改善了水质并促进了生长。组合生物过滤器（浮萍-贻贝）和过滤单元降低了运营成本，同时在RAS系统中保持了较高的鱼类存活率。活体生物过滤器的整合提供了无需化学添加剂的可持续水处理方法，适用于小规模水产养殖作业。
