台湾海峡蓝圆鲹的食性研究

本文材料系1965年，1977年，1988年至1989年台湾海峡灯光围网、拖山网的渔获物。采用个体百分比（N），重量百分比（W），出现频率（F），出现频率百分比，胃饱满系数，类群更替率等指标进行分析，并根据3个指标，计算了相对重要性指标。蓝圆鲹食性广泛，主要食料有桡足矣、小型鱼类、糠虾类、长尾类和短尾类等。幼鱼食料以桡足类最为重要，成鱼食料则以鱼类为重要。蓝圆鲹摄食强度有明显的季节变化。周年摄食强度呈双峰型，高峰期正好比两个产卵期迟1个月，说明蓝图鲹生殖后强烈摄食。幼鱼摄食强度昼夜变化明显，以黄昏和黎明摄食较强烈。蓝图鲹主要饵料生物的高生物量区，可作为寻找中心渔场的良好生物学指标之一，这在生产实践中有重要意义。

Feeding habits of Decafterus maruadsi in Taiwan Strait

Decapterus maruadsi was collected by light-seining and trawl during the investigations in 1965, 1977 and 1988~ 1989 in theTaiwan Strait. Number of indiidvuals,percentage weight,Percentage of occurrence frequency, coefficient of stomach fullness,and rate of exchange of Population were taken as indices in the analysis of feeding habits of the young aud mature fishes. According to the three measures above,we assessed the dietary importance of a prey group i. e. IRI (Index of Relative lmportance): IRl = (N W)F.D. maruadsi shows its euryphagy and its major prey consists of Copepoda,small fishes, Mysidacea, Macruran, and Brachyura. Copepoda is the most important to young fish, and small fishes the most important to mature D.maruads.The feeding intensity shows apparently seasonal varlation in an annual cycle for D. maruadsi with a feeding maximum in after one month of spawning,and diurnal varlation in a daily cycle for young fish with a maximum during dark hours and at dawn. This is of consid erable significance in fishing practice.The major prey anlmals. may play a good biological indicator in locating-D.;naruads cen tral field,which more possibly Iocates in an area with more abundant prey animals.