水產養殖池的生態管理

Ecological Management for Pond Aquaculture

水產養殖環境管理的好壞是水產養殖生產成功與否的關鍵之一。養殖活動越密集，對於生態系統與環境的衝擊也越大。有機負載增加、氧氣供應不足，以及有機質分解、轉化與同化速率的遲滯造成了營養循環的減緩、還原態毒性物質的累積、病原的滋生等各種緊迫頻繁發生，終致危及養殖生物的成長與活存。針對以上養殖活動對生態的衝擊，筆者從水質和底泥兩方面提出改善的原則與管理的對策及作法。水質管理的目標係：提供優良水質、降低毒性物質的濃度、減少水質的變化。作法有：施行有效率的餵飼策略、將養殖系統保持在高度氧化的狀態、以換水來減少毒性物質、以穩定的浮游植物的群聚來吸收毒性物質、以有益微生物的群聚來轉化毒性物質、添加化學物質及生化物質來調整水質。底泥管理方面，認識底泥在養殖生態系統的重要角色，以及底泥的特性及如何惡化，包括(Eh)在底泥的分佈及變化過程以及影響底泥Eh的各種因數。底泥管理的原則包括：減少有機負載並強化分解，加強氧化，加厚氧化層（保護層），促進底泥緩衝能力及穩定度，建立改善底泥的方法及操作，包括：生產期間池底的維護，做好水質管理、中央排汙、以及改良底泥的措施等，以及休養期間的整池操作。

The quality of environmental management in aquaculture is one of the keys to the success of aquaculture production. The more intensive the farming activities, the greater the impact on the ecosystem and the environment. The increase in organic load, insufficient oxygen supply, and the retardation of organic decomposition, transformation, and assimilation rate have caused various urgent and frequent occurrences such as the slowdown of nutrient turnover, the accumulation of reduced toxic substances, and the propagation of pathogens, which eventually jeopardize the growth and survival of farmed organisms. In view of the impact of the above aquaculture activities on the ecosystem, the author puts forward the principles of improvement and management countermeasures and practices from the aspects of water quality and sediment. The objectives of water quality management are: to provide excellent water quality, reduce the concentration of toxic substances, and reduce fluctuations in water quality. Practices include: implementing efficient feeding strategies, maintaining the culture system in a highly oxidized state, changing water to reduce toxic substances, stabilizing phytoplankton community to absorb toxic substances, converting toxic substances thorough the supplement of beneficial microorganisms, and adding chemicals and biochemicals to adjust water quality. In terms of sediment management, the important roles of sediment in the aquaculture ecosystem, as well as the characteristics of sediment and how it deteriorates, including the distribution and change process of reduction-oxidation potential (Eh) in sediment and various factors affecting sediment Eh are all elaborated. The principles of sediment management include: reducing organic load and enhancing decomposition, enhancing oxidation, thickening the oxidized (protective) layer, promoting the buffering capacity and stability of sediment, and establishing methods and operations to improve sediment, including maintenance of the pond sediment during production, water quality management, central sewage discharge, and measures to improve sediment, etc., as well as operations for the rejuvenation of whole pond during the rest period.