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Growth and maturation of Sepioteuthis lessoniana in the coastal waters of North Taiwan
|Authors: ||Chiao-Wen Lin|
|Contributors: ||NTOU:Institute of Marine Affairs and Resource Managemen|
Sepioteuthis lessoniana;Statolith;Growth;Maturation;Coastal waters of North Taiwan;Environmental factors
|Issue Date: ||2011-11-23T03:25:57Z
|Abstract: ||軟絲鎖管(Sepioteuthis lessoniana) (以下簡稱軟絲)分布於印度–太平洋沿岸水域。臺灣之軟絲為經濟價值較高之物種，但其族群結構與漁業生物學資訊相當有限。因此本研究目的為：(1)研究臺灣北部沿岸水域之軟絲族群，以平衡石微構造定齡並分析其成長與成熟；(2)探討環境狀態對其成長與成熟之可能影響。於2009年4月至2010年3月間，採集基隆嶼週邊水域釣捕之軟絲共341尾。由其體長範圍為81-401 mm，體重為49-3284 g，體長–體重關係式雌雄間無顯著差異。共定齡271尾軟絲，其生命週期約7個月。由平衡石輪數回推孵化日後發現，軟絲族群幾乎終年產卵(除1-2月外)，雌軟絲之孵化高峰在9月，雄軟絲為8月。以體長–日齡對應資料套用成長模式，雌、雄軟絲之最佳成長模式相同：體長皆為Gompertz成長函數，體重皆為乘冪式成長。由生殖腺指數判斷生殖投資，以雌軟絲較高。成熟日齡與成熟體長皆是雌(23 wks, 231 mm)比雄(21 wks, 220 mm)大。為探討不同環境水溫狀態下對成長與成熟之效應，將軟絲依孵化初期三個月之環境表水溫分成冷水群(SST <23 ºC, 對應孵化月為10月至3月)與暖水群(SST >26ºC, 對應孵化月為5月至9月)。雌、雄軟絲在上述兩季節群之成長模式相同。雌軟絲之成熟頻度曲線分季節群後，其解釋能力皆有增加(R2值增加)，但雄軟絲則無此現象。雌軟絲冷水群之成熟日齡較晚，成熟體型較大，生殖投資較少。此結果建議軟絲成熟過程之環境狀態，對其成長與成熟有明顯效應。|
Sepioteuthis lessoniana distributes in the coastal waters of Indo-Pacific. This species is a highly commercial loliginid species in Taiwan, but limited information of population structure and fisheries biology is known so far. Thus the objectives of this study: (1) Age determination by statolith microstructure and analysis growth and maturation of S. lessoniana in the coastal waters of North Taiwan; (2) Discussed the influences of environmental conditions on growth and maturation. A total of 341 samples of squids were collected from waters around Keelung Islet between April 2009 and March 2010. The range of dorsal mantle length (ML) and body weight (BW) was 81-401 mm and 49-3284 g, respectively. The length-weight relationship was the same between sexes. A total of 271 samples of squids were aged and the lifespan were ca 7 months. The hatching dates were determined by back calculated the number of increments of statolith. The squid hatched almost all year-round (except January and February) and peaked at September for female and August for male. Use back-calculated size-at-age data and fitted with growth patterns. The best growth patterns were the same between sexs: Gompertz growth function for both ML and was power model for both BW. The reproductive investment as measured by gonadosomatic index was higher in females than males. ML and age at sexual maturity was larger in females (23 wks, 231 mm) than males (21 wks, 220 mm). In order to investigate the effects of environmental conditions on growth and maturation, separated groups of squid hatched under mean sea surface temperature (SST) during the first 3 months of life, the cold cohort (CC, SST >26ºC, hatching between October and March) and the warm cohort (WC, SST >26ºC, hatching between May and September). The same growth pattern between the 2 cohorts in both sexs. The explanatory power of maturation curves of females was increased (R2 value increased) after grouped but this was not the case for males. Female CC matures later and in larger size and lower reproductive investment than WC. The results suggest that during the maturation process, the significantly effects of environmental conditions for the growth and maturation of S. lessoniana.
|Appears in Collections:||[海洋事務與資源管理研究所] 博碩士論文|
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