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海流對箱網底部抬升及容積變化之影響

  • 出版日期:104-06-30
  • 標題title(英):
    Influence of Current Forces on Cage Deformation and Volume Changes
  • 作者:楊清閔‧黃星翰‧賴繼昌‧蘇宏盛‧翁進興‧吳龍靜
  • 作者auther(英):Ching-Min Yang, Hsing-Han Huang, Chi-Chang Lai, Hung-Sheng Su, Jinn-Shing Weng and Long-Jing Wu
  • 卷別:23
  • 期別:1
  • 頁碼:23-33

海洋箱網養殖的袋網容積變化關係到產業界決定魚隻放養數量與年間收益。然而,運用實際箱網進行海流對箱網抬升影響與容積變化之研究稀少。本研究以屏東縣車城鄉圓框式箱網進行實驗,於箱網底部四端點設置深度監測與流速流向儀,分析箱網受海流抬升之影響。結果顯示,大、小潮期間之下午及晚上時段明顯以向南流為主,大潮期之流速超過 10 cm/sec以上頻度 (40%) 明顯較小潮期 (24%) 多,亦以向南流居多。向南流之流速超過 10 cm/sec時易引起箱網底部北端點抬升,流速每增加 10 cm/sec箱網底部抬升約 1.3 ~ 1.5 m。平均向南流速由 10 cm/sec 增強至 30 cm/sec 時,網成形係數平均由 0.80 降至 0.59。箱網容積的穩定狀態在 80 ~ 90%,若平均向南流超過 20 cm/sec 以上且持續時間長 3 ~ 4 h,則易造成箱網袋網嚴重變形達 50 ~ 70%。本研究成果將可提供現場產業對箱網在開發設計與減少海流影響的配置一些參考依據,減少網具變形與保有最大的養殖空間,提高生產的效能。

摘要abstract(英)


The volume changes of sea cage nets affect the number of fish to be farmed and farmer's annual income. However, there is a lack of research involving the use of actual cages to investigate how current forces lift the cage nets and thus change their volumes. This study analyzed the influence of current forces on the lifting of a cage net by monitoring four points on the cage bottom, as well as the current velocities and current directions. The results showed that in the afternoon (12:00-18:00) and at night (18:00-24:00) during spring tide and neap tide, southward current flows clearly dominated. In addition, the percentage of occurrence of current velocities exceeded 10 cm/sec during the spring tide was 40%, which was greater than that of neap tide (24%). When the southward current velocity exceeds 10 cm/sec, it easily causes lifting of the cage bottom on the north end of the cage, and with every increase of 10 cm/sec in current velocity, the bottom of the cage is lifted by about 1.3-1.5 m. When the average southward current velocity increases from 10 cm/sec to 30 cm/sec, the net shape coefficient reduces from 0.80 to 0.59 on average, and the stability of the cage net volume is 90%. If the average southward current velocity exceeds 20 cm/sec and lasts for 3-4 hours, it easily causes serious deformation of up to 50-70% of the volume of cage net. These results can serve as a reference for the industry in the development and design of cage nets, as well as in the configuring of nets, to reduce the influence of current forces, which, in turn, would improve productivity by reducing the degree of net deformation to maintain the largest culture spaces possible.