光密度與光週期對於泥鰍──山蘇浮筏式魚菜共生系統的水質與作物產量的影響

本研究在於探討光密度與光週期對於泥鰍（Loach, Misgurnus anguillicandatus）與山蘇（Nest fern, Asplenium nidus）在魚菜共生系統中的生產的影響。以光合光量子通量密度（photosynthetic photon flux density, PPFD）為基準的 3 階層的光密度（22, 59, 109 μmol sec-1m-2 的 T5 螢光燈） × 2 階層的光週期（一日 3 或 6 小時）所形成的 6 處理，被逢機的分派到 12 個養殖槽，每槽為單一之浮筏魚菜共生系統含泥鰍與山蘇。12 週的生產期間，在無換水的操作下，水僅損失 8.9%，或是每日 0.1%。水的損失主要來自於葉面的蒸散及餵食區水的蒸發。水質保持得安全且穩定，無泥鰍死亡。整體的增重，泥鰍為 124.5%、山蘇為 167.5%。高的光密度及長的光週期對於泥鰍與山蘇的成長及水質的改善都是有利的，亦即減緩水中氮及磷的累積，因而降低生物需氧量及化學需氧量以及緩和酸鹼度的下降。浮筏式魚菜共生系統在節水、營養鹽保存及泥鰍與山蘇生產上皆顯示有效率。以較長的養殖期來養出較大的泥鰍及較高的山蘇產量是可行的，同時在此魚菜共生系統也可產生較大的利潤。

This study focused on effects of photoperiod and light intensity on production of loach and a shade or low light plant, Nest fern Asplenium nidus Linn. A factorial arrangement of 6 treatments, 3 light intensities in photosynthetic photon flux density (22, 59, 109 mmol s
1 m
2 with T5 tube) X 2 photoperiods (3-h or 6-h light per day) were assigned to 12 tanks. Each tank was an aquaponics system containing fish, loach Misgurnus anguillicandatus and raft-supporting plant, Nest fern A. nidus Linn.. Water loss was 8.9% or 0.1% d
1 in 12 weeks' production period, due to leaf transpiration mainly and evaporation in the feeding area. Water quality remained safe and stable. No fish died. Overall average weight gain was 124.5% for fish and 167.5% for plant. High light intensity and long photoperiod favored both plant and fish growth and improved water quality, such as lessened the accumulation of nitrogen and phosphorus nutrients in water, consequently, lowered BOD and COD and slowed down pH de line. This raft aquaponics system was demonstrated effective in water saving, nutrient conservation and fish and plant production. Longer culture period is feasible for bigger loach and higher fern production, consequently, more lucrative profit in this aquaponics system.