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研究報告

更新日期: 2015-02-09
點閱數: 1,425

美洲大赤魷漁海況暨資源研究

年度 2013
計劃名稱 美洲大赤魷漁海況暨資源研究
中文摘要 美洲大赤魷(Dosidicus gigas)為大體型之外洋表層魷類,主要分布於東太平洋水域。其為東太平洋海洋生態系之主要組成物種之一,於1970年代開始成為商業漁業之目標物種。 漁業壓力對美洲大赤魷族群生物量變動之影響,以及連帶之生態系效應,為漁業生態學家之關注焦點。臺灣美洲大赤魷之漁業規模雖然不大,但此漁業可為阿根廷魷添加量不足時之替補,且大赤魷目前為南太平洋區域漁業管理組織之管理目標物種,對其族群動態、海洋生態及漁業管理等有必要密切觀察。本研究應用臺灣美洲大赤魷漁業資料,探討族群資源量變動趨勢及環境因子效應。 美洲大赤魷空間分布以秘魯北部近岸水域較高。 近年之體型組成皆以大體型群為主。 由GAM分析顯示,時、空間變數對大赤魷資源量變異量之解釋能力較佳,可能反映大赤魷具相當的年間變異,及高度的近岸、遠岸洄游型態。由相對資源量指標顯示,自2005年以後逐漸降減。 以Depletion方法估算大赤魷期初資源量,在2002-2012年間平均比例逃逸量為52%,高於目前建議之魷類漁業管理目標(40%)。 近年漁船之空間分布樣式與早年(2007年前)不同,可能反映大赤魷族群空間分布樣式之改變,或潛在之環境狀態改變之影響。 後續研究應考慮規畫適當之生物標本採樣,及增加可能影響大赤魷資源量環境變數之討論。
英文摘要 The jumbo (or Humboldt) squid, Dosidicus gigas, is a large pelagic ommastrephid squid which distributed in the Eastern Pacific Ocean (EPO). The jumbo squid is an important component of its ecosystem in the EPO and is the main target of squid fisheries in this region. The central challenge for fisheries ecology is to understand the abundance variations of resources under fishing pressure and its synergistic effects to the ecosystems. The jumbo squid fishery in Taiwan is not dominant in context of production or values, while it could act as a substitute for Illex argentious fishery. Also, jumbo squid has been a target species of SPRFMO which enter into force on 23 September 2012. Therefore, it is essential to understand its population dynamics, environmental influences and fisheries management. This study applied fisheries data of D. gigas fishery in Taiwan to explore the variation of stock abundance and the environmental influences. The distribution of D. gigas abundance was higher in the coastal waters off northern Peru. The size composition harvested by Taiwanese fleet was identified as large-size group in recent years. The results of GAM showed the temporal and spatial variables could explain higher variation of squid abundance than other variables. This may result from highly variable features of squid populations and high migration pattern of jumbo squid. A decreasing trend of squid abundance index was found since 2005 afterward. The average annual proportional escapement in 2002~2012, which estimated by depletion method, was 52% which higher than the management target (40%) suggested in the Illex fishery. The annual spatial patterns of fishery in recent years were different from the earlier years (before 2007) which may imply a change in migration pattern for the jumbo squid, or a potential change in the environmental conditions of habitat. Designing and collecting biological data, and including more environmental variables in models may improve our understanding to variability of abundance for jumbo squid in the EPO.
計畫編號 102農科-11.1.1-漁-F5(1)
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