南海北部陆坡海域秋季金鼻眶灯鱼的摄食习性

Feeding habits of Diaphus chrysorhynchus from continental slope region in northern South China Sea in autumn

根据2014年10月对南海北部陆坡海域进行中层鱼拖网调查所获得的金鼻眶灯鱼(Diaphus chrysorhynchus)样本,采用胃含物分析方法,对其食物组成、摄食强度、食物多样性、摄食习性随体长的变化和营养级等进行了初步研究。结果表明,金鼻眶灯鱼属浮游动物食性,以浮游甲壳动物(桡足类、磷虾类等)为主要摄食对象,其中桡足类为绝对优势饵料生物类群,其相对重要性指数百分比(%IRI)、个数百分比(N%)、质量百分比(W%)和出现频率(F%)分别为74.00、85.64、18.39和100.00。金鼻眶灯鱼摄食等级较高,摄食率为100%,胃饱满指数平均为2.68%。不同体长组所摄食的饵料生物类群基本相同,没有发生明显改变,体长达60 mm后大个体种类摄食比重加大,有可能出现食性转变现象。金鼻眶灯鱼的营养级为3.49级,属第三营养级的低级肉食性动物。

Based on the samples collected by a mid-water trawl in the epipelagic zone of continental slope region in northern South China Sea in October,2014,we examined the diet composition,feeding intensity,diversity index,ontogenetic feeding habit shifts and trophic level of Diaphus chrysorhynchus by traditional stomach content analysis. The results show that D. chrysorhynchus from the continental slope region in the South China Sea were classified as a zooplankton carnivorous predator,with planktonic crustaceans（ copepoda,euphausiacea,etc.） as the main prey groups. Among the crustaceans,copepoda was the most dominant prey group,and the relative importance index percent（ % IRI）, individual percentage, quality percentage and occurrence percentage were 74. 00,85. 64,18. 39 and 100. 00,respectively. The feeding intensity of D. chrysorhynchus was high with a total feeding rate of 100%. The average percentage of stomach fullness index was 2. 68%. There was no significant difference in preys among different standard-length groups. The standard length（ 60 mm） was the turning point of diet,and the bigger prey groups in diets increased for fish body lengths longer than 60 mm. The trophic level of D. chrysorhynchus was 3. 49,which indicates that this species belongs to third-grade and lower carnivore animals.