title: A data-mining framework for exploring the multi-relation between fish species and water quality through self-organizing map.
abstract: The steep slopes of rivers can easily lead to large variations in river water quality during typhoon seasons in Taiwan, which may poses significant impacts on riverine eco-hydrological environments. This study aims to investigate the relationship between fish communities and water quality by using artificial neural networks (ANNs) for comprehending the upstream eco-hydrological system in northern Taiwan. We collected a total of 276 heterogeneous datasets with 8 water quality parameters and 25 fish species from 10 sampling sites. The self-organizing feature map (SOM) was used to cluster, analyze and visualize the heterogeneous datasets. Furthermore, the structuring index (SI) was adopted to determine the relative importance of each input variable of the SOM and identify the indicator factors. The clustering results showed that the SOM could suitably reflect the spatial characteristics of fishery sampling sites. Besides, the patterns of water quality parameters and fish species could be distinguishably (visually) classified into three eco-water quality groups: 1) typical upstream freshwater fishes that depended the most on dissolved oxygen (DO); 2) typical middle-lower reach riverine freshwater fishes that depended the most on total phosphorus (TP) and ammonia nitrogen; and 3) low lands or pond (reservoirs) freshwater fishes that depended the most on water temperature, suspended solids and chemical oxygen demand. According to the results of the SI, the representative indicators of water quality parameters and fish species consisted of DO, TP and Onychostoma barbatulum. This grouping result suggested that the methodology can be used as a guiding reference to comprehensively relate ecology to water quality. Our methods offer a cost-effective alternative to more traditional methods for identifying key water quality factors relating to fish species. In addition, visualizing the constructed topological maps of the SOM could produce detailed inter-relation between water quality and the fish species of stream habitat units.
authors.affiliation: Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan, ROC.
authors.forename: Wen-Ping
authors.initials: WP
authors.lastname: Tsai
authors.affiliation: Biodiversity Research Center, Academia Sinica, Taiwan, ROC.
authors.forename: Shih-Pin
authors.initials: SP
authors.lastname: Huang
authors.affiliation: Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan, ROC.
authors.forename: Su-Ting
authors.initials: ST
authors.lastname: Cheng
authors.affiliation: Biodiversity Research Center, Academia Sinica, Taiwan, ROC.
authors.forename: Kwang-Tsao
authors.initials: KT
authors.lastname: Shao
authors.affiliation: Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan, ROC. Electronic address: changfj@ntu.edu.tw.
authors.forename: Fi-John
authors.initials: FJ
authors.lastname: Chang
mesh_terms: D000465:Algorithms; D000818:Animals; D057919:Biological Oxygen Demand Analysis; D057225:Data Mining; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D005399:Fishes; D016571:Neural Networks, Computer; D010758:Phosphorus / Q000032:analysis; D013624:Taiwan; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data*
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus
keywords: Artificial neural network (ANN); Eco-hydrological environments; Fish community; Flow regime; Self-organizing map (SOM); Water quality