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Title: | 阿根廷魷洄游之時間及空間動態分析 Temporal and spatial variation of migratory Argentine shortfin squid (Illex argentinus) |
Authors: | Hsiu-Jun Hsu 徐秀君 |
Publication Year : | 2001 |
Degree: | 碩士 |
Abstract: | 阿根廷魷(Illex argentinus),又稱為阿根廷短鰭魷(Argentinean short-finned squid),分佈在西南大西洋,為全球頭足類漁業最主要的漁獲物種之一。過去的研究發現,阿根廷魷至少有三個以上的系群,目前比較確定的是冬季產卵系群(winter spawning stock)與夏季產卵系群(summer spawning stock),冬季產卵系群是支持大型魷漁業的主要部分。冬季產卵系群又可分為體型較小的「陸棚群」(shelf group)及體型較大的「斜坡群」(slope group)。在攝食期間,該系群往南洄游,其中只有斜坡群會到達50°S以南的區域;進行產卵前洄游時,斜坡群係沿著大陸斜坡北返,而陸棚群則可能經由陸棚外緣北返。上述的洄游模式乃透過一年的資料所推論,其是否具有年間一致性仍待考驗。 為探討台灣魷釣漁業利用相下,阿根廷魷的系群結構與系群動態。本研究合併台灣魷釣漁船的漁獲資料與生物資料,分析連續三年(1997-1999)的CPUE月別時空分佈以及體長組成的月別時空變化。資料分析之前,先對所有漁船的漁獲努力量進行標準化程式,並據之計算CPUE做為有效的族群豐度指標。結果發現: 1.漁獲努力量的標準化使得在特定時空作業的船隊的CPUE之變異量降低了原本的11%。 2.漁業利用相下,可觀察到阿根廷魷的兩個系群,一為冬季產卵系群,另一個可能是春季產卵系群。春季產卵系群於五至八月間出現在42-46°S陸棚。由於該系群的觀察結果有限,因此難以說明其動態。 3.冬季產卵系群於每年十一月至十二月出現在45-47°S的陸棚及陸棚外緣,並於二月時移向47-49°S的陸棚。冬季產卵系群可再被分為體型較小的小型群與體型較大的大型群。三月,小型群移往45-49°S的陸棚外緣開始北返,大型群則繼續向南移動至50-54°S。四月,大型群移往45-50°S的陸棚外緣,並於五、六月時開始北返。在十一、十二月至四、五月間,冬季產卵系群的體長隨時間相應增大。 The Argentinean short-finned squid, Illex argentinus, is an important commercial species, distributed widely in the southwest Atlantic. Previous studies have found that the species consists of at least three stocks, among which the winter spawning stock and summer spawning stock are more widely confirmed. The winter spawning stock is targeted by major fishery. This stock is divided into the “shelf group” with smaller body sizes and the “slope group” with larger body sizes. The stock migrates southward for its feeding, but only the slope group reaches south of 50°S. As the squids enter prespawning phase, the slope group migrates north along the slope, while the shelf group may migrate north along the outer shelf. Because this migration model was based on one year's data, further research is needed. The objective of this study is to investigate the stock structure of I. argentinus and the temporal-spatial dynamic of these stocks. Fishery data and biological data collected from Taiwanese jiggers (1997-1999) were combined to analyze the distribution of monthly CPUE and the temporal-spatial variation of body length composition. All fishing efforts are first standardized and used to calculate the abundance index, catch per unit effort (CPUE). Major findings are: 1. Standardization of fishing efforts are effectively reduced the variation of CPUE by 11% when specific abundance is estimated. 2. Two stocks of Illex argentinus can be observed in the fishing phase: The winter spawning stock and the spring spawning stock, the latter, however, needs further confirmation. The spring spawning stock is observed on shelf between 42-46°S from May to August. Further information is needed to describe their temporal-spatial dynamic. 3. The winter spawning stock is observed on the shelf and outer shelf between 45-47°S in November or December. In February, the stock moves to the shelf between 47-49°S. This stock can be categorized into a small-sized group and a large-sized group. The small-sized group moves to the outer shelf between 45-47°S in March and then turns northward, while the large-sized group continues southward to 50-54°S; In April, the large-sized group moves to the outer shelf between 45-50°S and then turns northward in May or June. From November or December to April, the body length of winter spawning stock increases with time. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/75241 |
Fulltext Rights: | 未授權 |
Appears in Collections: | 動物學研究所 |
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