|Abstract: ||本研究針對臺灣龜山島海域產美軟魚(Malakichthys elegans)之漁業生物學進行研究，採樣期間自2010年11月至2012年1月止，共計採得樣本1299尾，其中雌魚648尾、雄魚649尾、無法辨識2尾。本種全長(TL ,cm)與體重(BW ,g)的關係式經變積分析檢定後有顯著差異，故分開表示，分別為雌魚：BW = 0.0206TL2.8678 (n=648)，雄魚：BW = 0.0163TL2.9384 (n=649)。本種耳石的輪紋一年形成一輪，輪紋形成期在每年的11月至隔年1月間，雌、雄魚之輪紋數最多分別可讀至8輪和7輪;本種依非線性迴歸法所估算之von Bertalanffy成長方程式經檢定有顯著差異，故雌魚：Lt=21.02(1-e-0.3016(t+1.0318)) (n=319)，雄魚：Lt=18.78(1-e-0.448(t+0.2529)) (n=299)，而以體重(g)表示則分別為Wt=127.93(1-e-0.3016(t+1.0318))2.8678 (雌魚)及Wt=90.08(1-e-0.448(t+0..2529))2.984 (雄魚)。本種週年均有產卵跡象，但其產卵盛期在每年的9月至隔年1月間，50%性成熟體長雌魚約16.5 cm、雄魚約16.0 cm，而其產卵型態型態則為非同步成熟型(Asynchronous)。孕卵數在5,159粒至21,128粒之間；而其性比除了2011年4月至7月、11月及12月外，其餘月份雌雄均無顯著差異。本種肥滿度週期較不明顯，唯秋冬季似有稍高於春夏季的情形，而肝臟指數雌雄之季節變動亦不大，但非產卵盛期的1~7月似乎相較於其他月份為高；內臟指數則在10月以後有較為明顯的上升趨勢，並在隔年1月降至相對低值，由於本種主要攝食季節亦在秋、冬之際，故推論其生殖期間能量來源除部分來自肌肉、肝臟與內臟外，亦須靠不斷的攝食而得。|
Fisheries biology of Malakichthys elegans in surrounding waters of Guei-Shan Island, Taiwan was examined based on samples collected between Nov. 2010 and Jun. 2012. In total, 1299 specimens including 648 males, and 649 females, as well as 2 sex undifferentiated individuals were collected. Significant difference in total length – body weight relationships between sexes was found. The separated equation for females is BW = 0.0206TL2.8678 (n=648), and BW = 0.0163TL2.9384 (n=649) for males. The formation of annuli for this species was found between November and January. The maximum ages for female and male fishes were estimated to be 8 and 7, separately. The von Bertalanffy growth equation in length (cm) which was found to be different between sexes, were Lt=18.8169(1-e-0.6156(t+0.6843)) (n=319) for females, and Lt=18.1372(1-e-0.588(t+0.3335)) (n=299) for males. In terms of weight, they were Wt=93.11(1-e-0.6156(t+0.6843))2.8678 for females, and Wt=81.35(1-e-0.588(t+0.3335))2.984 for males. The species spawn all year round with a peak occurred between September and January. The size at 50% maturity for females was 16.5 cm, and 16.0 cm for males. An asynchronous oocyte development pattern also was found for the species, and the fecundity was estimated to be ranged from 5,159 to 21,128. There was no difference in sex ratio for most months except for period between April and July, and November and December of 2011. Seasonal variations in condition factor (CF) for both sexes was less evident, with relative high values occurred during the fall and winter. The hepatosomatic index (HSI) also showed minor seasonal variations, with relatively high value occurred in the none spawning season, while the visceral index (VI) showed an increasing trend after October and dropped to low value in January. Because major feeding activity of the species also occurred in fall to winter period, it was suggested that energy required for spawning for M. elegans may be fueled partially by the reserves in muscle, liver and visceral, and partially from continuous feeding.