Shahidul Islam Md, Jahangir Sarker Md, Yamamoto Tamiji, Abdul Wahab Md, Tanaka Masaru
Laboratory of Marine Stock Enhancement Biology, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
Mar Pollut Bull. 2004 Mar;48(5-6):471-85. doi: 10.1016/j.marpolbul.2003.08.025.
The present study aimed to quantify the water and sediment quality and growth and production parameters and to establish nutrient budgets for an average of five selected semi-intensive shrimp ponds in Bangladesh over a growing cycle. Physico-chemical parameters of water and sediments were measured and analyzed by standard methods. Gross yield (kg ha-1) of shrimp was calculated from the stocking and harvesting data. Finally, a partial nutrient mass budget for N and P was calculated. Most of the parameters of water and sediments correlated significantly with each other suggesting a high degree of interactions between different parameters in the system. Significantly higher concentrations of all species of nitrogenous nutrients were recorded in the effluent waters than that entering into the ponds. Therefore, a high loading and net output of nitrogenous nutrients in effluent waters was documented. The study also indicated a net discharge of solids and minerals through effluent loading. However, significantly lower concentrations of phosphorus in the effluent water indicated a net retention and trapping of phosphatic nutrients in the environment. Total production ranged between 532.0 and 697.0 kg ha-1 cycle-1 and P. monodon production between 484.0 and 562.0 kg ha-1 cycle-1. Ponds gained nitrogen primarily from intake water (55%) and fertilizers (29%), and nitrogen was lost primarily from water exchange (78%) and harvested shrimp (12%). Phosphorus gain occurred mostly from intake water (52%) and fertilizers (25%), and phosphorus was lost primarily from water exchange (52%) and harvested shrimp (3.3%). About 10% of input nitrogen and 44% of phosphorus were not accounted for in measured losses, and presumably were fixed or metabolized in the system. On average, 78 g N was discharged to and 25 g P was removed from the surrounding water by the system for each kilogram of shrimp produced. Mean conversion of feed nitrogen and phosphorus to shrimp flesh averaged 74% and 40%, respectively. It was concluded that semi-intensive systems serve as net supplier of N to and net remover of P from the surrounding water.
本研究旨在量化孟加拉国5个选定的半精养虾塘在一个养殖周期内的水质、沉积物质量、生长和生产参数，并建立养分收支。采用标准方法对水和沉积物的理化参数进行了测量和分析。根据放苗和收获数据计算虾的总产量（千克/公顷）。最后，计算了氮和磷的部分养分质量收支。水和沉积物的大多数参数之间存在显著相关性，表明系统中不同参数之间存在高度相互作用。出水中所有种类含氮养分的浓度均显著高于进入池塘的水。因此，记录到出水中含氮养分的高负荷和净输出。该研究还表明，通过排放负荷，固体和矿物质有净排放。然而，出水中磷的浓度显著较低，表明环境中磷养分有净保留和截留。总产量在532.0至697.0千克/公顷·周期-1之间，斑节对虾产量在484.0至562.0千克/公顷·周期-1之间。池塘主要从进水（55%）和肥料（29%）中获取氮，氮主要通过换水（78%）和收获的虾（12%）损失。磷的获取主要来自进水（52%）和肥料（25%），磷主要通过换水（52%）和收获的虾（3.3%）损失。约10%的输入氮和44%的磷在测量的损失中未得到解释，推测它们在系统中被固定或代谢。平均而言，每生产1千克虾，系统向周围水体排放78克氮，从周围水体中去除25克磷。饲料氮和磷向虾肉的平均转化率分别为74%和40%。研究得出结论，半精养系统是周围水体氮的净供应者和磷的净去除者。
