|Abstract: ||銀紋笛鯛 (Lutjanus argentimaculatus)，俗名紅槽，為臺灣漁業十大經濟魚種之一，亦為近年來增殖放流之重點目標物種，然過去對本種之漁業生物學研究甚少。為進行臺灣週邊海域銀紋笛鯛之漁業生物學研究，並瞭解是否存在地區間差異，本研究將採樣區分為東北部及西部等進行比較。採樣時間自 2017年1月至 2018年11月按月採集樣本，共採集 336尾，其中雌魚 117尾，雄魚 77尾，性別尚未分化之個體為 93尾，無生殖腺之個體數為 49尾，總體性比為0.60，經卡方檢定顯示雌雄樣本數量不具顯著差異。所有樣本之全長 (TL)範圍為 122 - 972 mm，體重 (TW)範圍為 34 - 12796 g，全長與體重之關係式性別間具顯著差異，區域間則不具有顯著差異。 年齡成長分析以耳石之橫切片作為定齡工具，先計算耳石邊緣成長率(Marginal increment ratio, MIR)，確認銀紋笛鯛之輪紋形成週期為一年，並在每年5月開始形成新的明帶。而雌、雄魚分別採捕到之最大年齡為 42、29歲。將所有成功判讀年齡之個體資料套入范式成長方程式 (Von Bertalanffy growth equation, VBGE)，經檢定顯示性別間不具有顯著差異，合併雌雄所有樣本後所得之成長參數分別為 L∞= 877 mm、k= 0.18、t0= −1.48，成長方程式在各區之性別間亦不具有顯著差異，然各區間則具有顯著差異，表示臺灣周邊海域之銀紋笛鯛族群成長模式略有差異，未來在漁業管理應用上應列入考量。 生殖生物學部分，根據生殖腺指數 (Gonadosomatic index, GSI)之月別變化、外觀及其組織切片與等方法，結果顯示生殖腺指數與群成熟度之月別變化皆以4 - 9月具有較高的比例，並推估銀紋笛鯛之生殖季節為4 - 9月，高峰為 5 - 6月及9月，雌、雄魚之 50% 性成熟體長分別為全長606 mm、475 mm，50% 性成熟年齡分別為 4.5歲、2.5歲，並為雌雄異體之魚種，根據結果可知雄魚應較雌魚早熟。銀紋笛鯛之總孕卵數平均為2,867,167 ± 430,916顆，相對總孕卵數平均為398 ± 292粒卵/克，並由於缺乏水卵期之卵粒，本研究以計數胚胞移動期之卵粒為單次孕卵數，其單次孕卵數平均為122,905 ± 23,577顆，相對單次孕卵數平均為12 ± 11粒卵/克。 綜合上述，臺灣地區銀紋笛鯛之成長參數在地區間具有差異，性別間不具顯著差異，然雄魚成熟較早。本研究首次呈現臺灣周邊海域之銀紋笛鯛野外族群漁業生物學結果，未來可供管理、環境及人類活動影響之參考基準。|
Lutjanus argentimaculatus, commonly known as mangrove snapper, is one of the high economic fish species in Taiwan and is also a key target species for stock enhancement in recent years. However few researches have focused on the fishery biology of this species in Taiwan coastal water. To estimate the growth parameters and to understand whether geological differences exist, current study collected specimens from northeastern and western for comparison. Sampling time was from January 2017 to November 2018 for each month. A total of 336 fish was collected, including 117 females, 77 males, 93 sex undiffenrtiation ,and 49 with undeveloped gonad. Overall, female to male ratio is 0.60, and the chi-square test showed no significant difference between sex samples. The total length (TL) ranged from 122 to 972 mm and the total weight (TW) ranged from 34 to 12796 g. The relationship between TL and TW showed significant differences between sexes, but not significant differences between sampling areas. The otolith sections were used for age determination. Marginal increment ratios (MIR) verified the otolith rings formed annually, and the formation of translucent zone began from May. The maximum age of female and male fish was 42 and 29 years old, respectively. Von Bertalanffy growth equation (VBGE) was used for growth parameters estimating of mangrove snapper, and no significant difference were found between the sexes, so the growth parameters of sex-pooled samples are L∞= 877 mm, k=0.18, and t0=−1.48. There is no significant difference in the growth equation between sex in each sampling area. However, there are significant differences between sampling areas, indicating that the growth patterns of the mangrove snapper in the surrounding waters of Taiwan are slightly different, and should be put into consideration when applying on fishery management. According to the reproductively biology analysis, the results show that the Gonadosomatic index (GSI) and the group maturity rate both were higher from April to September, speculated to be its reproductive season peaking at May to June and September. The length at 50% maturity of female and male fish is 606 mm and 475 mm, respectively. And the age at 50% maturity is 4.5 years and 2.5 years old, which indicating it is a gonochoristic species. According to the results, male matured earlier than female. The average number of total fecundity of the mangrove snapper was 2,867,167 ± 430,916, and the relative total fecundity was 398 ± 292 eggs/g. Due to no occurences of the hydrated oocytes stage egs sample, the eggs in migratory nucleus stage were counted. The number of batch fecundity was 122,905 ± 23,577, and the relative batch fecundity was 12 ± 11 eggs/g. In conclusion, mangrove snapper in Taiwan waters showed varied growth parameter spatially, but same between sex. Therefore, the age and length at 50% maturity differed between sex, and male matured earlier. Present study showed the complete fishery biology information of wild mangrove snapper population in Taiwan, and can used as the background information for future research on fishery management, environmental change and anthropogenic influences.