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Use of otolith microstructure and microchemistry to study life history of the slickhead Alepocephalus bicolor in the northeastern water off Taiwan
|Authors: ||Jyun-Ruei Chen|
|Contributors: ||NTOU:Institute of Marine Biology|
deep-sea;otolith;microstructure;microchemistry;age and growth;habitat transition;life history
|Issue Date: ||2011-07-04
|Abstract: ||黑頭魚 (Alepocephalus bicolor) 為台灣深海優勢魚種之一。本研究於2004至2007年在台灣東北部沿岸海域定期進行底拖網採集，藉由生物學參數測定以及耳石構造與微化學解析，以瞭解黑頭魚未知的生活史歷程。體長頻度分析顯示黑頭魚棲息在400~600 m水深，體長隨著深度而增加，主要集中在160~220 mm之間。族群以雄魚居多，雌魚所佔的比例則隨著體長增加。生殖腺指數顯示其性成熟體長約為雄魚155 mm及雌魚200 mm，生殖季持續自二月至八月。黑頭魚耳石上可發現規律性形成的成長帶與成長輪紋，以及孵化、首次攝食、變態期等記號與透明區結構。耳石變態期記號後形成之成長帶應不為日周輪；成長輪紋經邊緣成長率分析驗證為年輪，形成時間約為每年的二月至三月。耳石透明區形成時之逆算體長約為84 mm、理論年齡約為7.7歲，推測其可能與生殖腺初始發育或棲地轉移有關。黑頭魚最大年齡達23歲，范氏成長曲線參數之極限體長約為277 mm、成長率0.10 yr-1。各生活史時期耳石元素組成具有明顯的差異，其中鍶鈣比與鎂鈣比為分群判別之主要依據。綜觀黑頭魚的生殖與生活史資訊，顯示其屬於偏K選擇之物種特性。|
The slickhead Alepocephalus bicolor is the dominant species in deep-sea fish fauna of Taiwan. To understand the unknown life history pattern of the fish, biological measurements as well as otolith structural and microchemistry analyses were conducted on regularly collected samples by the demersal trawl in coastal water of NE Taiwan during 2004 and 2007. Length frequency distributions indicated that the fish inhabited in 400~600 m depth and lengths of the fish, mainly of 160~220 mm, increased with the depth. Males predominated the population and the large-sized individuals skewed toward females. Gonadosomatic indexes indicated that lengths at maturity were 155 mm for male and 200 mm for female with a prolonged spawning season from February to August. Periodically formed growth increments, growth rings, checks of hatching, first feeding and metamorphosis (MC) and a structure of translucent zone (TZ) were discernible in otolith of fish. The growth increments beyond MC did not deposit daily, whereas the growth rings were validated to be annuli that formed every February to March by marginal increment analysis. Back-calculated length and age of the fish when TZ formed were 84 mm and 7.7 yr, which otolith structure might be related to the initial development of gonad and habitat transition of the fish. Longevity of the fish were of 23 yr and the von Bertalanffy growth parameters were 277 mm for L∞ and 0.10 yr-1 for K. Differences of elemental composition in otoliths of the fish among life history stages were discriminated mainly by Sr/Ca and Mg/Ca ratios. Generally, the combined information on reproduction and life history indicated that the slickhead displayed K-select tendencies.
|Appears in Collections:||[海洋生物研究所] 博碩士論文|
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