台灣中部筏子溪魚類豐度及歧異度與水質關係之研究

Abundance and Diversity of Fishes in Relation to Water Quality in the Fazih River of Central Taiwan

本研究以台中盆地西側之筏子溪為研究樣區，選擇由上游連仔溪橋（F1）至下游集泉橋（F5）共5個測站進行魚類及水質變化之探討。魚類調查時間為2000年9月至2007年2月，共進行67次現場調查；水質資料採用環保署全國環境水質監測資訊網所公告之東海橋（F2）及集泉橋（F5）水質數據進行分析。研究結果發現，台灣特有種及外來種會受到降雨量、降雨天數的影響，導致魚類豐度及種歧異度減少；而台灣特有種與WQI8呈現負相關，與BOD呈現正相關，外來種則與重金屬砷呈現負相關趨勢；台灣特有種與外來種之魚類群集，並具有相互消長之現象，意即外來種會抑制台灣特有種群集豐度的發展。廣布性魚種由於環境適應力較強的關係與降雨及水質無相關性趨勢。此外，筏子溪水質因受到中科台中園區營運及台中市整體污水處理率改善之影響，分別對水質產生劣化及改善的結果。 Fish samplings were conducted seasonally with electrofishing and fish trapping methods at five different polluted zones of Fazih River, 2000 to 2007. Water quality data were obtained from the National Water Quality Monitor Network, and precipitation data from the Taichung Station of the Taiwan Central Weather Bureau. The results showed that abundance of endemic species and exotic species were significantly, negatively correlated to precipitation, number of raining days, and water quality indices (WQI8), but positively correlated to BOD and river pollution indices (RPI). The exotic species were negatively correlated to arsenic concentrations. There was the presence of interspecific competition between endemic species and exotic species. No significant correlation was found between the abundance of generalist species of fishes and precipitation, water quality, PRI-values, and WQI8-values, suggesting their high tolerance to water pollution and environmental modification. The relationships between the water pollution and wastewater discharges from the Taichung Science Park and the Taichung City were discussed.