以多變量分析探討翡翠水庫水質與魚類群聚結構關係

The relationship of water quality and fish community structures by using multivariate statistical analysis in the Feitsui Reservoir

范慎芸(Shen-Yun Fan)

指導教授 ： 侯文祥

國立臺灣大學/生物資源暨農學院/生物環境系統工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201700267

摘要

翡翠水庫全水域內自2006至2016年，累計了1006筆數的十一項水質參數的水質資料；也在水域內9個水區累積了共35次的魚類相調查資料。為了瞭解冷暖季及不同水域中水質與魚類相之關係，本研究以多變量分析統計法，將翡翠水庫水區分為上游、中游、下游三個水域以及全水域進行兩種資料間關係之分析。
以主成分分析(PCA)探討翡翠水庫水質的重要參數。以魚類群聚結構分析魚類相資料，群聚結構以多元尺度分析、相似度分析及相似度百分比分析三種方法魚類在冷暖季、2010年前後以及每次採樣中是否有發生群聚結構之變化，以及導致變化的優勢種魚種為何。最後以線性回歸進行優勢種魚類與水質主要參數資料的相關性分析。
PCA分析結果顯示，翡翠水庫水質主要受季節性的藻類濃度消長以及不同水域之卡爾森指數值有不同影響，卡爾森指數值從上游至下游遞減。此外卡爾森指數值也是影響上中水域的水質因素，下游水域則是另外受集水區土壤沖刷影響。
群聚結構分析結果顯示，翡翠水庫全水域魚類在不同年份有群聚結構的差異，表示魚類結構在變動狀態，其中以高身鯽的變動幅度最大。中游水域需要注意的魚種是珍珠石斑，珍珠石斑為中游水域在2016年與其他年份在群聚結構造成差異的魚種之一，表示珍珠石斑的出現已經開始影響中游水域的魚類群聚結構。
魚類網捕密度與水質關係的分析結果顯示，上中游水域的吳郭魚與葉綠素a有正相關，代表吳郭魚在上中游水域對於水質可能具有負面影響。下游水域則是黑鰱與藻個數及葉綠素a有負相關，黑鰱在下游水域對於藻類可能具有清除效果。

關鍵字

翡翠水庫 ； 多變量分析 ； 卡爾森指數 ； 水質 ； 魚類群聚結構

並列摘要

The 1006 water quality datas including 11 kinds of water quality parameters were collected from 2006 to 2016 at Feitsui Reservoir. Also the 35 times fish community structures were investigated in these years including 9 water areas at Feitsui Reservoir. Multivariate statistical analysis was used to understand the relation between water quality parameters and fish species in different water temperature and different water area. The water area of Feitsui Reservoir were devided four parts, including upstream, midstream, downstream and all water area, and analyzed the relations between water quality factor and fish community structure of the every water area.
Principal component analysis (PCA) was used to analyze the water quality and to find major water quality parameters and influence factors of the reservoir. The fish community structures were analyzed by multidimensional scaling analysis (MDS), analysis of similarities (ANOSIM) and similarity percentage (SIMPER). We compared the fish community structure by three category including warm and cold water temperature, before and after 2010 as well as different years. We also used linier regression to find the relations between fish speices and water quality parameters.
The results of PCA showed that the water qualities of Feitsui reservoir were majorly affected by seasonly fluctuation of algae and the degree of Carlson trophic state index (CTSI) in diffent water area. The degree of CTSI decreased from upstream to downstream. The degree of CTSI was also the influence factor in up and mid stream. The influence factor of downstream was scour of surface soil of catchment area.
The results of fish community structures analysis indicated that the community structures of whole Feitsui reservoir were distinct from different years. This meant that fish community structures of Feitsui reservoir were unstable. The number of Carassius cuvieri in particular fluctuated. In midstream water area, Cichlasoma managuense should be kept under observation because the increasing number of Cichlasoma managuense changed the fish community structures in 2016.
The relations between fish standing crop and water quality indicated that tilapias (Oreochromis sp.) had positive relation with chlorophyll-a in upstream and midstream water area. It means that tilapias could affect water quality negatively. In downstream water area, bighead craps (Aristichthys nobilis) had negative relation with algal biomass and chlorophyll-a. It means that bighead craps could clean up the algae in downstream water area.

並列關鍵字

Feitsui Reservoir ； Multivariate analysis ； Carlson trophic state index (CTSI) ； Water quality ； fish community structures

參考文獻

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