Reproductive Biology of Codlet Bregmaceros Lanceolatus in the Coastal Waters off Southwestern Taiwan

臺灣西南沿海產尖尾海鰗鰍（Bregmaceros lanceolatus）之生殖生物學研究

10.29822/JFST.201309_40(3).0002

邱萬敦(Wann-Duen Chiou)；林志文(Ge-Wen Lin)

下雜魚 ； 底層棲地 ； 生殖 ； 臺灣 ； trash fish ； demersal habitat ； reproduction ； Taiwan

臺灣水產學會刊

40卷3期（2013 / 09 / 01）

153 - 169

英文

本研究探討臺灣西南沿海產尖尾海鰗鰍（Bregmaceros lanceolatus）之生殖生物學特性，研究期間從2005年10月至2006年9月，按月前往林園的中芸漁港，採集由拖網漁船所捕獲之尖尾海鰗鰍（進行實驗，共採得2,143尾樣本魚，雌魚1,606尾，雄魚537尾。以組織學方法將卵細胞之成熟階段分為八個階段，而卵巢的成熟過程可分為三個階段。根據肉眼觀測卵巢外觀、組織切片、生殖腺指數、不同性成熟階段頻度組成等四種方法，推斷雌魚終年皆有魚體產卵，而生殖盛期發生在6~7月、11月。本種魚的平均孕卵數為6,218 ± 2,684粒卵，平均單次產卵數為2,750 ± 1,257粒卵，單次產卵數（BF）隨體重（BW）增加而增多，其關係式如次BF = 605 x BW + 1.09 X 10^3（n = 34 ;r^2= 0.31）。全年各月別雌魚數量顯著多於雄魚（p ＜ 0.05），性比隨體長的增加而增大，尤其體長大於56 mm SL，雌魚顯著多於雄魚。雌雄魚之百分之五十性成熟體長分別為68.34 mm與55.90 mm SL。

This study aimed to investigate the reproductive biology of codlet Bregmaceros lanceolatus in coastal waters off southwestern Taiwan. A total of 2,143 specimens (1,606 females and 537 males) were collected monthly between October 2005 and September 2006 at Jhong-Yun fishing port, southwestern Taiwan. By means of histological examination, the oocyte development can be clearly categorized into eight stages while the ovary development into three stages. Based on the macroscopic appearance, histological examination of ovary, estimations of gonadosomatic index (GSI) suggest that its spawning period occurs throughout the year and peaks in November and June-July. Mean batch fecundity of codlets was estimated to be 2,750 ± 1,257. Batch fecundity (BF) increased with the body weight (BW) with an established equation as BF = 605 × BW + 1087 (n = 34, r^2 = 0.31, p ＜ 0.05). Sex ratio (females/total) was significantly different from 50% (χ^2, p ＜ 0.05), and skewed to female when their standard length (SL) larger than 56 mm. Sizes at 50% maturity (L_(50)) were estimated to be 68.37 mm and 51.67 mm SL for female and male, respectively.