东海和黄海南部发光鲷的摄食习性

On the feeding habits of Acropoma japonicum in the East China Sea and southern Yellow Sea

利用2008年5月至2009年2月在东海和黄海南部4个航次大面调查所获得的发光鲷（Acropoma japonicum）样本,采用胃含物分析法,对其食物组成、摄食强度、营养级及其随季节与体长变化进行了研究.结果显示,发光鲷摄取的食物种类有72种,精致真刺水蚤（Euchaeta concinna）、细螯虾（Leptochela gracilis）、太平洋磷虾（Euphausia pacifica）、七星底灯鱼（Benthosema pterotum）和中华哲水蚤（Calanus sinicus）是其主要食物种类,磷虾、十足类、端足类、鱼类和糠虾是其重要的食物类群.发光鲷不同季节和体长组食物类群的个数百分比与相对重要性指数百分比的差异均极显著,食物种类组成和优势种的替代也非常明显.发光鲷的总空胃率11.63％,胃饱满系数最高118.53‰,平均13.55‰.胃饱满系数的季节差异极显著,而体长变化不显著.发光鲷的营养级3.48级,春、夏、秋、冬4季依次为3.44、3.47、3.53和3.46级;≤50 mm、51～ 60 mm、61～ 70mm、71～80 mm和＞80 mm 5个体长组依次为3.42、3.46、3.45、3.47和3.60级.研究表明,发光鲷属次级消费层的低级肉食性动物.食性随季节和体长的变动而变化显著.在体长80 mm以前,以浮游动物为主食,兼食游泳动物.体长大于80 mm后,转向底栖生物/游泳动物（虾/鱼）食性.

The glowbelly （Acropoma japonicum） belongs to genus Acropoma in family Acropomatidae of order Perciformes.It is a kind of small fish widely distributed in the Indo-West Pacific.In the East China Sea and southern Yellow Sea,A.japonicum is an important part in the diet composition of big and medium-size economic fishes.Currently,its quantity and weight indicators top the list of dominant species of small fishes,and it plays a very important role in the fish community.It is necessary to carry out studies on the biology and ecology of A.japonicum.In this study,we investigated the diet composition,feeding intensity,and trophic level of Apogon japonicum using stomach content analysis based on the samples from four cruise surveys in the East China Sea and southern Yellow Sea from May 2008 to Feb.2009.The results showed that Acropoma japonicum mainly fed on crustacean,benthic shrimp and small fish belonging to 72 prey species of 16 big classes.And Euphausiacea,Decapod,Amphipoda,Pisces and Mysidacea were the most important prey groups.Euchaeta concinna,Leptochela gracilis,Euphausia pacifica,Benthosema pterotum and Calanus sinicus were the major food species of A.japonicum decapods,and their relative importance index percent added up to 78.35%.There were highly significant differences （P 〈0.01） for individual percentage and %IRI of prey groups in different seasons and body classes,and it was very obvious for diet composition and dominant species replacement.In different seasons,the diet composition in summer was the most abundant,and the dominance of diet dominant species in autumn was the most concentrated.In different body length groups,the group 71-80 mm was the most abundant and the dominance of diet dominant species in body length group ≤ 50 mm was the most concentrated.The main feeding of Apogon japonicum were planktonic animals and part of swimming animals during the body length group less than 80 mm.And when the body length was larger than 80 mm,it mainly feed on benthic / swimming animals （shrimp / fish） and the number of the diet species decreased significantly.The total empty stomach rate of A.japonicum was 11.63%,the empty stomach rate was the highest in autumn and the lowest in spring.For different body size groups,the lowest was in 51-60 mm,and the highest in 〉 80 mm.The fluctuation of the empty stomach accorded with its reproduction rate,and the stomach fullness index was 118.53‰,with the mean of 13.55‰.Significant seasonal differences （P 〈0.01） were observed in the stomach fullness index,but not in the body class.The trophic level of A.japonicum was 3.48,which was 3.44,3.47,3.53 and 3.46 from spring to winter,and 3.42,3.46,3.45,3.47 and 3.46 in size classes ≤50 mm,51-60 mm,61-70 mm,71-80 mm and 〉 80 mm,respectively.The results indicated that A.japonicum belonged to low-grade carnivore animals,and the feeding habits were closely related to its body length and seasonal changing.It mainly feeds on zooplankton and part of swimming animals,but the prey species will change to shrimp/fish when the body length is greater than 80 mm.The variation of feeding intensity of A.japonicum is closely related to its growth characteristics and reproductive biology.Standard length 80 mm is the turning point of diet from broad to narrow and trophic level from low to high.