臺灣東北海域鄰近湧昇流區磷蝦物種及生長階段組成之季節變化

Seasonal variation of euphausiid life stage and species composition near the upwelling site northeast of Taiwan

陳昱安(Yu-An Chen)

指導教授 ： 謝志豪

國立臺灣大學/理學院/海洋研究所/碩士(2021年)

https://doi.org/10.6342/NTU202103311

摘要

磷蝦廣布全世界的海洋且在海洋生態系扮演很重要的一環，因牠們是重要的漁業資源也是連接浮游生物與較高級消費者的重要橋梁。然而在臺灣附近海域對於磷蝦的研究相對稀少，因此本實驗的目的為探討磷蝦在臺灣東北海域鄰近湧升流之物種組成及生長階段組成的季節性變化，以及環境因子對於磷蝦季節性變化的影響。磷蝦樣本使用七年間總共二十一個航次在鄰近湧升流的固定採樣點的拖網樣本。在所有磷蝦樣本中二十個磷蝦物種被鑑定，其中有兩個物種(Euphausia nana和Peuseuphausia latifrons)為優勢種，佔百分之九十五的總磷蝦豐富度；E. nana 在春季及夏季為優勢種，而在秋季時E. nana與P. latifrons 同為優勢種。冗餘分析(redundancy analysis)的結果發現磷蝦物種組成及生長階段組成有明顯的季節性分群且被溫度、鹽度及葉綠素濃度影響。在物種組成的結果顯示有年間的生命週期變化，各個季節有相對優勢的生長階段且有逐漸成長的趨勢。本實驗發現在鄰近臺灣東北湧升流區的磷蝦物種組成有季節性的變化以及有年間的生命週期，這些變化受到環境因子影響。

關鍵字

磷蝦 ； 群聚結構 ； 生長階段 ； 水文 ； 湧升流區

並列摘要

Euphausiid is a family of crustacean who plays a critical role in marine ecosystems because they are commercial fishery targets and the primary prey of marine mammals, fishes, and seabirds. Despite of their ecological importance, we still have limited knowledge about the abundance, diversity and life stage variations of euphausiids in the East China Sea. To describe the abundance, diversity and life stage of euphausiids and investigate how they vary in different seasons, we used data collected at a sampling site (25.5oN, 121.9oE) northeast of Taiwan. We visited this site in 21 cruises from May 2010 to September 2016. We found that total abundance and diversity of euphausiids tend to be higher in summer to autumn season (June to November). In spring and summer, Euphausia nana was the dominant sepecies accounting for 90% of total Euphausiids abundance, while in autumn, Pseudeuphausia latifrons was the dominant species occupying 36% of total abundance. In terms of seasonal variations of euphausiids life stage, we found that larval stages (furcilia and calyptopis) were the dominant group in spring when upwelling is more prominent. On the other hand, post-larval stages (juvenile and adult) were more dominant in summer and autumn when upwelling is weaker and stratification is stronger. By describing the seasonal variations of abundance, diversity and life stage, this study provides the foundation to better understand euphausiids in the southern East China Sea.

並列關鍵字

euphausiid ； community structure ； life stage ； hydrography ； upwelling site

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