渤海主要生物种间关系及食物网的研究↑（*）

根据１９９２年－１９９３年渤海增殖生态基础调查大面定点底拖网试捕的渔获物，对渤海２７种鱼类和１０种虾蟹类的３８０１个胃含物样品进行了分析，并与１０年前渤海鱼类的食性进行了比较。结果表明：蓝点马鲛、小黄鱼和白姑鱼等主要捕食鱼类胃含物中鱼的比例较１０年前明显增加，鱼类的食性类型无明显变化。渤海低级肉食性鱼类的营养级由１９８２－１９８３年的平均２．４上升为２．５，中、高级肉食性鱼类的营养级分别由原来的平均３．２和３．８降为２．８和３．３。渤海主要鱼类之间饵料重叠系数大于０．６的占１５％。鱼为渤海多数中、高级肉食性鱼类的主要摄食对象。

SPECIES INTERACTION AND FOOD WEB OF MAJOR PREDATORY SPECIES IN THE BOHAI SEA

A total of 3801 stomachs from 27 fish species, 10 shrimp and crab species was analysed. Samples were collected during the trawl survey of marine living resources covering large area in the Bohai Sea from 1992 to 1993. Comparison was made between the current results and those from ten year ago. The results indicated that the proportion of anchovy in the stomach of major species such as Scomberomorus niphonius, Pseudosciaeua polyactis and Argyrosomus argentatus etc. in the period 1992 to 1993 increased comparing to that in the period 1982 to 1983. NO significant changes in the feeding type was found. The average trophic level of lower carnivorous fishes increased from 2.4 to 2.5 during the past ten years whereas the average trophic level of mid and high carnivroous fishes decreased from 3.2 and 3.8 to 2.8 and 3.3 respectively. The diet overlap between major predatory species larger than 0.6 made up 15% of the total pairs. Anchovy was found the major species on which the predatory species preyed.