Please use this identifier to cite or link to this item:
The mean trophic level of set-net fishery landings in Taiwan during the period 1991~2008
|Authors: ||Chao-Yi Yu|
|Contributors: ||NTOU:Department of Environmental Biology and Fisheries Science|
Set-net fishery;Mean trophic level;Fishing-in-balance index;Season Index
|Issue Date: ||2011-06-30T08:24:28Z
|Abstract: ||摘要 本研究利用宜蘭-新協發、台東-三仙台、屏東-滿豐及苗栗-日豐四處定置網漁場歷年漁獲紀錄資料，配合各漁獲魚種之營養位階(TL)指標值，推估此四處定置網漁場之平均營養位階(MTL)與漁獲平衡指數(FiB)的變動趨，同時以比率移動平均法(ratio-to-moving- average method)求取季節指數(Season Index, SI)，並以ANOVA檢定決定季節性之魚種，探討季節性魚種時序漁獲量之變化情形。其結果分述如下： 一、根據此四處定置網漁場歷年漁獲量與MTL變動趨勢顯示，宜蘭-新協發與屏東-滿豐定置網漁場，有從高漁獲量及高MTL，逐漸往低漁獲量及低MTL變動之趨勢；而台東-三仙台與苗栗-日豐定置網漁場則呈現低漁獲量及低MTL往高漁獲量與高MTL變動之情形。 二、由四處定置網漁場歷年FiB指數之變動顯示，宜蘭-新協發與屏東-滿豐定置網漁場之FiB 指數多為負值，顯示此二處定置網漁業資源之食物網結構，有逐年弱化之情形；而台東-三仙台與苗栗-日豐定置網漁場之FiB 指數則為正值。 三、季節性指數分析之結果顯示，宜蘭-新協發與屏東-滿豐定置網漁場中，春季型魚種的漁獲比例均佔40%以上；而台東-三仙台定置網漁場中，春季型魚種之漁獲比例則有逐年減少之趨勢，相對的秋、冬季型魚種之漁獲比例則逐年增加；至於苗栗-日豐定置網漁場中，則是以秋季型魚種之漁獲比例有逐年增加之趨勢，反之春冬型魚種則逐年減少。 四、此四處定置網漁場之生態指標與年平均SST 之變動關係顯示，宜蘭-新協發定置網漁場自1996年後，其漁獲量與SST之間有顯著的正相關；而其他三處定置網漁場亦顯示，各定置漁場之MTL與SST之間有顯著的正相關。|
Abstract The mean trophic level (MTL) and the fishing-inbalance (FiB) index were estimated by the set-net fishery landings from Xinxiefa-Ilan, Sanxiantai-Taitung, Manfeng- PingTung and Rifeng-Miaoli fishing grounds in the coastal waters of Taiwan. We also used ratio-to-moving-average method to calculate Season Index (SI), and examine seasonality by ANOVA. Then, we analyzed the composite seasonality changes hidden in the landing data. The results of this study were summarized as follows: 1. The annual MTL and landings in Xinxiefa and Manfeng fishing grounds were decline gradually, but rose in Sanxiantai and Rifeng fishing grounds. 2. The FiB indexes were mostly lower than 0 in Xinxiefa and Manfeng fishing grounds. It meant that the structure of food pyramid for the set-net fishery were weaken even more. Contrarily, the FiB indexes were mostly higher than 0 in Sanxiantai and Rifeng fishing grounds. 3. SI showed that the ratio landings of spring species were greater than 40% in Xinxiefa and Manfeng fishing grounds. While, the ratio landings of spring species were reduced gradually in Sanxiantai fishing grounds, but the ratio landings of autumn/winter species were increased gradually. Besides, the ratio landings of autumn species were increase gradually, but the ratio landings of spring/winter species were reduced gradually in Rifeng fishing grounds. 4. The correlation analyses suggested that the landings and SST had highly relationship in Xinxiefa fishing grounds. While, the correlation analyses suggested that the MTL and SST had highly relationship in the other fishing grounds.
|Appears in Collections:||[環境生物與漁業科學學系] 博碩士論文|
Files in This Item:
All items in NTOUR are protected by copyright, with all rights reserved.