圖書典藏及影音數位平台

為了維護居民生命財產安全及發展經濟，多年來興設許水利構造物，無形中卻也影響河川環境生態。為降低工程的負面影響，水利署近幾年來努力尋找生物與環境間的關係，即是希望透過此一關係瞭解工程設置或相關管理措施對生物所造成的影響。過去曾嘗試辦理魚類適合度曲線的相關研究，以流速、水深及底床粒徑等工程人員孰悉的參數，透過調查、統計建立魚類適合度(喜好)的關係曲線，水利工程人員僅需透過水理模式即可瞭解工程設施對水理條件的影響進而推求魚類適合度的變化，相關曲線目前已有相當廣泛的應用。惟過去僅針對頭前溪、烏溪、楠梓仙溪等建置魚類適合度曲線，未能含括多數的臺灣原生魚類，且相同魚類在不同溪流亦有不同的曲線，因此本計畫將擴大辦理，並增加魚類生活史的探討，瞭解原生魚種生殖周期與對於自然棲地的選擇及偏好，以補充水理參數外的相關資訊，作為水利工程規劃及河川經營管理亟需的基本生物參數。除將相關成果建置資料庫以方便管理使用外，也將研擬魚類棲地適合度調查技術作業手冊，使調查方法與努力量標準化，讓後續的調查能有一定的品質要求與依據。

The Da-an River, which was selected for studying reach, is administered by central government and located in the central Taiwan. During March to December 2017, totally 390 specimens of Formosan river loach (Hemimyzon formosanus) located in Da-an river, were collected to measure the external morphology traits including BL (body length), TL (total length), body weight, and the second sexual symbol such as nuptial tubercles and nuptial colorations. Then all the fish samples were soaked in 75% alcoholic solution and carried back to the laboratory to measure and analyze Condition Factor (CF), Gonadosomatic Index (GSI) and Hepatosomatic Index (HSI). Egg numbers and diameters of the mature female individuals were counted as well. It showed that September and from March to April might be loach’s primary and secondary breeding. As the estimation of fecundity shows, the average egg number was 145 eggs/individuals and 1.617 mm in egg diameters (N=26). But we will discuss and analysis after the completion of the annual sampling analysis is done. We made monthly collections and investigations of fish from March to September 2017. The 600 sampling grids (1.5 m × 3.0 m) were sampled with electro-fishing at 60 stations. Each with 10 grids for habitat suitability curve (HSC). In the fish micro-habitat investigation, a total of 23 species ,which were belonged to 10 families of fishes with 3,064 specimens, were collected in the end of the investigation. The population of dominant fish is Tanakia himantegus (23.2%). During the investigation, the range of water pH is between 7.8 to 8.7, and conductivity of the water is between 247 μs/cm to 2,380 μs/cm. Moreover, dissolved oxygen in the water is between 7.06-10.09 mg/L. The water quality in samplings stations were classified as Category B except pH. The occurrences and CPUE (Catch Per Unit Effort) of T. himantegus, R. candidianus, O. barbatulum, A. paradoxus and A. paradoxus were used for the establishment of water velocities, water depths and river substrate HSC. Besides, we have held two colloquia on fish HSC for five species in Beinan river. To promote the application of the fish HSC, the fish HSC, life history database and website were established this year. There were Front-Ended and Back-Ended interfaces on the website. Front-Ended is a multi-user operating system designed for IBI (Index of Biotic Integrity), fish HSC application and life history, Back-Ended is a data management interface, and it is only accessible by the authorized database manager. Flow regimes are well known as the driving force dominating biotic dynamics in rivers. The Instream Flow Incremental Methodology (IFIM) was proposed by the U.S. Fish and Wildlife Service (USFWS) to evaluate the Instream Flow Need (IFN). The meso-habitat model PHABSIM incorporating IFIM has been widely used to evaluate optimal ecological flows instead of Q95. But it is incapable of resolving microhabitats. The Canadian 2D micro-habitat model River 2D can evaluate the suitability of micro-scale habitats like riffle, pool, and run through a 2D mesh. However, it still doesn’t integrate IFIM procedure and is not capable of riverbed change simulation. Mobile bed models are available for alluvial river simulation. But they are not capable of evaluating habitat suitability. A web post-processing procedure graphical user interface (GUI) for habitat suitability evaluation was developed in this study. Last year, we had dealt with the SRH-2D model, which was introduced under the Taiwan-US water resources technical supporting protocol. In this year, we have dealt with the CCHE-2D model, which was introduced by the Water Resources Planning Institute.