跳到主要內容區塊

研究報告

更新日期: 2015-02-09
點閱數: 3,605

台灣地區鰻魚資源量及棲地現況研究

年度 2014
計劃名稱 台灣地區鰻魚資源量及棲地現況研究
中文摘要 一、 日本鰻是東亞各國水產養殖的重要魚種之一,具有極高的經濟價值。雖然人工繁殖已在日本與韓國成功,但因成本過高而尚無法商業化量產,因此目前養殖所需的大量鰻苗仍然依賴天然捕撈,成為養殖產業的重大瓶頸。根據估計,東亞地區現今的日本鰻資源量相較於1970年代而言,估計低於當年的5-10 ﹪。日本鰻主要的養殖國家為日本、中國、韓國、以及台灣,每年鰻苗的需求量約在80-100公噸左右,然而,近幾年鰻苗捕獲量頻創新低,一尾鰻苗身價甚至高達200元,困擾著整個東亞的鰻魚產業。因此,建立適當的日本鰻資源管理與復育方針,有效增加天然鰻苗之資源,是現階段鰻魚產業能夠永續發展的關鍵。行政院農業委員會自2013年起,公告全國鰻苗捕撈漁期管制規定,捕撈許可時間訂為每年11月1日至次年2月28日;另各縣市政府亦已公告轄內指定河川,禁止使用任何方式採捕體長8公分以上之鰻魚;水試所每年亦進行種鰻放流工作,期望放流鰻能夠順利降海產卵。因此,本計畫擬 (1) 調查台灣地區鰻苗資源與分布現況; (2) 普查台灣地區河川中之鰻魚資源與捕撈現況; (3) 評估蘭陽溪流域,鳳山溪流域以及高屏溪流域之鰻魚資源量; (4) 調查各縣市鰻魚保護河川棲地長期變遷。計畫重要成果如下: 一、台灣地區共發現6種鰻魚,包括罕見之內唇鰻 (A. interioris)。由宜蘭河口鰻苗資源監測數據可知,今年度捕苗季 (11-2月) 日本鰻苗之平均CPUE (隻/網/小時) 值 30.8 較去年值10.4為高,顯示宜蘭河口之監測數據良好的反應台灣日本鰻苗資源量趨勢。而鱸鰻苗今年CPUE高峰值落在6-7月份左右,與往年在清明節前後與9月份不太相同。   二、台灣地區大多數河川因汙染嚴重,加上堤岸水泥化與上游引水,棲地破壞嚴重,鰻魚資源已經很少了,過去有許多專業捕鰻漁民現在幾乎都消失了,僅剩釣客與少數漁民於河口混獲抓到。目前日本鰻以宜蘭縣最多,30年前日本鰻遠多於鱸鰻,近年來日本鰻快速下降,已轉為鱸鰻多於日本鰻。花蓮台東地區主要以鱸鰻為主,但產量大不如前。 總體來說,台灣目前鱸鰻整體數量比日本鰻多,台灣一年由河川中捕獲之成鰻數量,日本鰻約在1公噸以下,鱸鰻約在5公噸以下,多由餐廳私下收購或是供自家食用,市場公開販售野生鰻魚已經不常見了。   三、蘭陽溪,鳳山溪以及高屏溪流域之中上游以電魚法進行調查,並於下游河口處設置蛇籠捕捉,自2013年11月21日放流開始至目前2014年11月中為止,以鳳山溪日本鰻資源最多。蛇籠大多反應日本鰻之資源,有明顯偏估現象。  四、河川棲地品質長期變遷推估結果發現,以Arc GIS分析河川棲地並計算HQI (有效棲地面積) 在1970年到2010年之變化值,蘭陽溪流域有效棲地面積共減少了百分之72,頭前溪流域共減少了百分之56,高屏溪流域則減少了百分之85,棲地品質顯著下降。
英文摘要 一、 Japanese eel is an important aquaculture species in East Asia with high economic value. Although artificial propagation of the glass eel has been successful, the commercial scale of production still cannot been established yet due to high cost. Thus, the needed fries are all caught from the wild till now, resulting in a serious bottleneck for the eel aquaculture industry. It is estimated that the current eel resource in East Asia is less than 5-10% in comparing to that in year 1970s. Taiwan also suffers the same impact. The Japanese eel is mainly cultured in Taiwan, China, Korea, and Japan, with mean elvers demand about 80-100 metric tons annually. However, the amounts of glass eel catch in recent years decline rapidly, with one piece of glass eel even charging more than 200 NTD. This seriously bugs the eel aquaculture in East Asia. Thus, to manage and recover the valuable natural eel resource is a key for the sustainability of eel aquaculture industry.   The Council of Agriculture announces the regulation of glass eel catching in year 2013. The glass eel are only allowed to be caught during Nov. 1st through Feb. 28th of the next year. Besides, all counties of Taiwan should choose at least one river as the eel protection river. Eel larger than 8 cm are not allowed to be caught in order to protect the seawater migration of the wild and released eels. Besides, Fisheries Research Institute performs eel stock releasing every year to hope that the released eels could go seawater migration and spawning. Thus, the aims of this project are: (1) To investigate resource status and distribution of the glass eel in Taiwan; (2) To investigate the eel resource and catch status of rivers around Taiwan; (3) To investigate the eel resource status of Lanyang Rivers, Kaoping Rivers and Toucian Rivers; (4) To investigate the long-term change of the eel habitat quality of eel protection rivers.   The present results include: 1. There are a total of 6 eel species found in Taiwan, including the very rare A. interioris. The mean CPUE (individuals/hr/net) of the Japanese eel between Nov.-Feb. of this year in Yilan River eatuary is higher than that of the last year (30.8 vs. 10.4), suggesting good correlation to the total catch of the Japanese glass eels in Taiwan. The peak CPUE of A. marmorata occurs around Jun.-Jul. in this year, different to the usual two peaks occurring around Apr. and Sep., respectively. 2. The eel habitat quality of rivers is bad in Taiwan due to pollution, river bank cement and re-directing of river water. The wild eel resource is scare now. The professional eel catchers are almost disappear nowadays; eels are by catch by only some fishing people and fisherman. The Yilan County has most abundant Japanese eel resource in Taiwan. 30 years before the Japanese eel is far more abundant than that of the A. marmorata, now the ratio reversed due to rapid loss of the Japanese eel. In Hualiang and Taidong Counties, A. marmorata is more abundant, but also suffer resource decline. Overall, the resource of A. marmorata is more than that of the Japanese eel, with annual catch in Taiwan below 5 and 1 tons, respectively. They are bought by some local restaurants or eaten by the catchers, and very few wild eels are sold in the market. 3. The eel resource status of Lanyang Rivers, Kaoping Rivers and Toucian Rivers are investigated by electric fishing in the up-stream and by net trap in the estuary. From Nov. 21, 2013 through middle Nov., 2014, Fengshan Rivers have most abundant Japanese eel resource. The catch data by net trap mostly reflect the Japanese eel and thus have some bias. 4. By using Arc GIS to analyze the long-term changes (between 1970-2010) of river habitat quality, the HQI (habitat quality index), the HQI of Lanyang Rivers decrease 72%, the Toucian Rivers decrease 56%, and the Kaoping Rivers decrease 85%. The quality of eel river habitat decreases significantly in the past 4 decades.
計畫編號 103農科-11.3.4-漁-F1(1)
網站導覽錨點