2009-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/698339摘要：日本鰻 (Anguilla japonica) 是一種降海洄游的魚類，擁有複雜的生活史。其孵化後之柳葉鰻隨著北赤道洋流以及黑潮漂送4-6個月，到達東亞陸棚後變態成為鰻苗，分佈於菲律賓、台灣、大陸、韓國與日本。近20年來，台灣以及東亞每年天然鰻苗的漁獲量尚因不明原因而呈現高度波動的情形，形成鰻魚養殖產業發展上之重大瓶頸，以及資源管理上之困難。本研究室以台灣漁業年報所統計之近35年來之日本鰻鰻苗產量進行分析，發現了 5-6 年週期性之波動規律，極可能與日本鰻之生殖週期與聖嬰-南方震盪 (ENSO) 現象有關。因此，本計劃的主要目標與工作項目為： 一、 探討日本鰻生殖週期與鰻苗產量波動之關係: 日本鰻鰻苗產量 5-6 年週期性之波動規律，極可能與日本鰻之生殖週期有關。因此，本計劃擬蒐集 1998-2010年本實驗室在高屏溪持續監測日本鰻資源量之資料庫，分析降海之種鰻與鰻苗來游之相關性，並&#63965;用耳石定齡方法，分析種鰻之成熟年齡，驗證日本鰻之生殖週期與鰻苗產量波動間之關係。 二、 探討日本鰻鰻苗產量之波動與聖嬰-南方震盪之關係: 研究已發現，許多海洋生物之生產量與 ENSO 之變化有高度相關。因此，ENSO變遷造成洋流的改變，理論上會影響日本鰻鰻苗輸送與成長。因此，本計劃將利用美國國家海洋氣象局氣候預報中心之數據，分析1972-2010年聖嬰-反聖嬰現象與日本鰻鰻苗產量之關係。本計劃亦將利用美國與台灣之高解析洋流資料庫，分析北赤道洋流以及黑潮之動態對日本鰻鰻苗產量之影響，建構鰻苗產量預測模型。 <br> Abstract: The Japanese eel (Anguilla japonica) is a catadromous fish with a complex life cycle. Its larva, leptocephalus, drifts from their spawning grounds with the North Equatorial Current (NEC) and then the Kuroshio Current (KC) for 4-6 months to reach the coasts of East Asia, south from the Philippines, Taiwan, China, Korea, and north to Japan. The annual catch of elvers of the Japanese eel, however, has fluctuated highly in East Asia in the past decades, which places the eel aquaculture industry under high risk and makes resource management difficult. We have analyzed data on the catch of elvers from 1972 to 2008 in Taiwan. The peak elver catch fluctuated in a cyclic change of 5 - 6 yrs. Our hypothesis is that the fluctuation in the recruitment of elvers is likely influenced by biotic factors such as the abundance of spawning stocks and also by environmental factors such as El Ni&ntilde;o/ La Ni&ntilde;a events and. Thus, the goal of this study aims to understand: (1) Fluctuation in the elver catch in relation to eel reproductive cycle: The peak elver catch fluctuated in a cyclic change of 5 - 6 yrs may be due to the reproductive cycle of the Japanese eel. We will analyze both the maturation age and cyclic changes in catch abundance of silver stage eels, collected in the Kaoping River of Taiwan from 1998 to 2010 by our lab, to verify the possible role of eel reproductive cycle on the fluctuation of elver catch. (2) Fluctuation in the elver catch in relation to the effect of ENSO events: The productivity of many marine organisms has been found to highly relate with changes in the El Ni&ntilde;o-Southern Oscillation (ENSO). The ENSO may also plays an important role in determining the recruitment fluctuation of elvers of the Japanese eel. The ENSO events during 1972-2010 will be based on data of the Climate Prediction Center of National Oceanic & Atmospheric Administration (NOAA). We will also analyze the high-resolution current data of NEC and KC to clarify the impact of oceanic current variations on success of elver recruitment and try to establish a prediction model for annual elver production.日本鰻產量周期性生殖週期聖嬰南方震盪洋流Japanese eelCatch periodicityReproductive cycleENSOOcean Current