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標題: | 耳石日周輪與鍶鈣比分析在銀魚洄游生活史之研究 Migratory life history of icefishes (Teleost: Salangidae) revealed by otolith daily increment and Sr/Ca ratio |
作者: | Chien-Yu Chen 陳建宇 |
指導教授: | 蕭仁傑(Jen-Chieh Shiao) |
關鍵字: | 銀魚科,耳石,日周輪,鍶鈣比,洄游生活史, Salangidae,otolith,daily growth increments,Sr/Ca ratio,migrating history, |
出版年 : | 2011 |
學位: | 碩士 |
摘要: | 銀魚(icefishes),屬於銀魚科(Salangidae),總共有5屬20種(劉等, 2000),主要分布於中國東部的湖泊、河川、河口及沿海等區域,但至今對其生活史及洄游模式仍沒有確切的證據,僅由少數捕撈及觀察記錄描述其生活史棲地選擇。本研究藉由耳石的日周輪及鍶鈣比分析,提供銀魚的洄游生活史的判斷,以釐清各種銀魚族群間是否有不同的洄游模式,及其生活史的多樣性。多數銀魚族群在春季及初夏期間耳石輪寬增長最快,夏末秋初則耳石成長逐漸緩慢並趨於穩定,顯示耳石的日輪寬度變化主要受季節性、溫度等因素影響;但其他的研究中也提出銀魚食性的轉變可能也是影響耳石增長速度的因素之一。從耳石日周輪所估算的孵化日期和前人的觀察記綠大致吻合。其中陳氏新銀魚主要於春季孵化;有明銀魚於冬季孵化;安氏新銀魚於春夏輪替之際孵化;中國大銀魚於冬末春初孵化。銀魚耳石鍶鈣比與環境鹽度呈現正相關(R = 0.93, p < 0.05),估計淡水生銀魚鍶鈣比上界為5.17‰,海水生銀魚鍶鈣比下界為14.38‰,界於兩者之間為半淡鹹水環境。利用既定的分界標準檢視各銀魚個體鍶鈣比時序列變化,可將各銀魚族群分為四種洄游模式:1. 狹域性淡水生,如太湖採集的陳氏新銀魚;2. 海水生,如陳氏新銀魚的珠江族群及安氏新銀魚的秦皇島族群;3. 典型溯河產卵型,如長江口的有明銀魚族群;4. 廣域性淡水生,如長江口和太湖內皆可採集之中國大銀魚族群。 Icefishes, belonging to Salangidae, consist of five genera, 20 species (Liou et al., 2000), which mainly distribute in the lakes, rivers, estuaries, and coastal area in the East China. This research studies their life history and migratory patterns by analyzing otolith microstructure and microchemistry. The otoliths of most Salangidae populations grow fastest in spring and early summer, and the growth rate gradually decrease and stabilize in late summer and early autumn. These results indicate that the increment of otolith is influenced by seasons and temperature. But the change of feeding niches may also affect otolith growth as reported in previous studies. Neosalanx tangkahkeii spawned in spring, Salanx ariakensis in winter, Neosalanx anderssoni during the late spring to early summer, and Protosalanx chinensis during the late winter to early spring based on the back calculation from daily growth increment. The otolith Sr/Ca ratio of icefishes is positively correlated with environmental salinity (R = 0.93, p < 0.05). The maximum value of otolith Sr/Ca for the freshwater population was 5.17‰ while the minimum value for the seawater population was 14.38‰. The values between 5.17‰ and 14.38‰ were defined as the brackish water environments. Chronological profile of otolith Sr/Ca ratio suggested four migratory types: (1) freshwater-restricted type, e.g. Neosalanx tangkahkeii in Taihu Lake; (2) seawater type, e.g. Neosalanx tangkahkeii in the Pearl River estuary and Neosalanx anderssoni in Qinhuangdao; (3) Anadromous type, e.g. Salanx ariakenesis in Yangtze River estuary; (4) freshwater-unbound type, e.g. Protosalanx chinensis in Yangtze River estuary and the Taihu Lake. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/32462 |
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顯示於系所單位: | 海洋研究所 |
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