南沙岛礁周围水域主要鱼类食物网

在南沙岛礁周围水域收集了43种主要鱼类,共940个胃含物,根据对它们的食性分析,并依其食料生物的生态类群以及消化器官特点,一般可划分为浮游生物食性、底栖动物食性、游泳动物食性、浮游生物兼底栖动物食性、底栖动物兼游泳动物食性等5种食性类型。根据食物网中各营养级的相互关系,初步划分为4个营养级,即初级生产者(海洋植物)、草食性动物和杂食性动物、低级肉食性动物和中级肉食性动物、高级肉食性动物。并根据这些营养级的划分,南沙岛礁周围水域43种主要鱼类可分低级肉食性鱼类,中级肉性鱼类和高级肉食性鱼类,它们的比为28105。灰裸顶鲷是南沙岛礁周围水域三重剌网举足轻重的捕捞对象,从食物网的观点出发,应加强灰裸顶鲷幼鱼期敌害鱼和其竞食者的捕捞,为低级肉食性经济鱼类除害,灰裸顶鲷就有可能增加资源量。

Main fishes food web in the adjacent waters area of Nansha Islands and reefs

43 main fish species were collected and 940 stomach contents be got altogether in the adjacent waters of Nansha Islands and reefs. Based on the food habits of those fish analyzed and their food organism ecological groups as well as their digestive organ characteristic, as a general, they may be divided into such five kinds of feeding habits as plankton feeding habit, benthos feeding habit, swimming animals feeding habit, both plankton and benthos feeding habit, both benthos and swimming animals feeding habits. Based on the relationship among each nutrient class in food web, they may primarily be divided into four nutrient classes, i.e., primary producer (marine plants), phytophage animals and miscellaneous feeding habit animals, low and middle carnivorous animals, high class carnivorous animals. And according to the nutrient class divided, 43 species may be devided into low class carnivorous fish, middle class carnivorous and high class carnivorous fish with ratio being 28:10:5 in the adjacent water area of Nansha Islands and reefs.Gymnocranius griseus (Tenminck et Schlegelel ) was the decisive fishing target by trammel net in the adjacent water area of Nansha Islands and reefs. From the view point of food web, it should be strengthened for fishing the enemy fish and competitor of G.griseus, in order to remove the enemies of low class carnivorous commercial fish, thus the biomass of G.griseus may increase.