牡蠣養殖對濕地淨化之管理策略評估-以新竹市濱海野生動物保護區為例

外文標題: 
Management strategy assessment of the wetland cleaning by oyster farming in Hsinchu City Costal Wildlife Refuge
校院系所: 
國立成功大學海洋科技與事務研究所
指導教授: 
張懿
出版年份: 
2013年
主題類別: 
摘要: 

近年來國際上對於濕地生態保育的呼籲不曾間斷,臺灣西部沿海一帶由北至南,牡蠣養殖區分佈廣泛且與眾多沿岸濕地分佈重疊;然而受沿海開發之影響,部分牡蠣養殖區或國家級濕地受到重金屬污染,新竹香山沿岸牡蠣養殖即是一受到影響之案例。從早期蓬勃發展之北台灣最大養殖產地至現今新竹香山牡蠣養殖業逐漸式微,可見重金屬污染之影響甚大,不僅當地漁民生計受害,對於臺灣濕地生態或國際形象皆有不良之影響;現階段新竹市政府已規劃新竹濱海野生動物保護區,採取牡蠣養殖離養計畫,對於任何養殖活動採取禁止的態度,但重金屬污染造成新竹香山濕地環境之生態平衡已被破壞,以此政策是否能達到復育之目標值得探討。
本研究以新竹濱海野生動物區為例,透過文獻回顧與案例分析嘗試瞭解以牡蠣養殖作為濕地復育中自然復育之工具,並評估其所造就之非食用效益,換言之,透過牡蠣特性所累積之重金屬濃度可以淨化水質的效益,將有機會大於販賣之經濟產值。本研究透過文獻蒐集找出牡蠣對重金屬蓄積濃度以及運用牡蠣年產量計算,得到單一牡蠣對於水中銅離子與砷離子之重金屬累積速率常數分別為446~1,066(mg/day)與3.21~4.63(mg/day),推測養殖一年的牡蠣體內銅累積量可高達512~1,201 (mg/kg),砷的累積量則約為2.21~3.97(mg/kg)(吳春吉,2006),經過初步計算,西元1995年新竹香山牡蠣年產量45噸應可吸附銅累積量約23,040~54,045(g) ,而砷累積量約為99.4~178.65(g);西元2010年牡蠣養殖產量降至6噸,據此推測吸附銅累積量約為3,072~7,206(g)與砷累積量13.26~23.82(g)。新竹當地年產量變化逐年降低顯而易見,但所失去可能之重金屬吸附量較不易令人發現。
本研究透過文獻分析及牡蠣養殖對於濕地之效益評估,試圖規劃牡蠣養殖於新竹濱海野生動物保護區內,每年預估政府提撥新台幣1千1百餘萬元進行管制採構回收,提供一個濕地復育之解決方案或契機,對於臺灣重要級濕地之復育或維護有相當的啟發。

外文摘要: 

In recent years, wetland conservation appeal had not been interrupted in the world. Oyster farming areas are widely distributed and overlapped with coastal wetland in the western coastal of Taiwan. However, coastal development affected some oyster farming areas or national wetlands by river born polluted water with heavy metals. The oyster farming in the coastal of Hsinchu Siangshan is one of the important cases. The heavy metal pollution impacts the oyster farming in Hsinchu Siangshan that the cultured oyster is out of use. It's not only affecting the livelihood of local fishermen, but also the wetland ecosystem service. The strategy of Hsinchu City Government is prohibiting any oyster farming activity by establishing Hsinchu City Coastal Wildlife Refuge. However, the ecological balance of the environment at Hsinchu Siangshan wetland has been broken, the policy of the restoration achieve is worth exploring.
In the case of Hsinchu City Coastal Wildlife Refuge, this study suggested to use oysters as a tool of natural recovery by literature review and case studies. Assessment of the effectiveness of the natural recovery by oysters was also discussed. We suggested that it may have an opportunity to purify the polluted water by restrictive oyster farming, but not for selling as food at all. Through the literature review and case analysis, we found that the uptake rate constants estimated for copper and arsenic are about 446~1066(1/day) and 3.21~4.63(1/day), respectively. Based on the predicted uptake rate constants, the accumulative amounts of heavy metal in oyster cultured for one year could reach 512~1201 (mg/kg) of copper and 2.21~3.97 (mg/kg) of arsenic. Oyster production in Hsinchu Siangshan were 45 tons in 1995 but sharply decreased to 6 tons in 2010. After preliminary calculations, the accumulative amounts of copper and arsenic in oyster are about 23,040~54,045(g) and 99.4~178.65(g), respectively in 1995, but they could be 3,072~7,206(g) and 13.26~23.82(g) in 2010.
This study provided a framework for wetland restoration by oyster farming at Hsinchu Coastal Wildlife Refuge and providing a solution by searching literature and assessment of oyster farming. The government should invest about 11 million per year to purchase the imitatively farmed oyster. It could be the way to recover both the polluted wetland and faded oyster farming fisheries.