用稳定氮同位素分析广东硇洲岛海域金线鱼营养级

Study on Trophic Level of Nemipterus virgatus in Naozhou Bay, Guangdong Using Stable Isotope Analysis Method

应用稳定同位素方法测定广东硇洲岛海域的金线鱼（Nemipterus virgatus）鱼肉、鱼鳃、内脏团和鱼鳞的稳定氮同位素，并计算出营养级。结果表明，在规格较一致的情况下，金线鱼各部位δ^15N值范围为10.09‰～14.07‰，其中，鱼肉δ15N值范围为11.56‰-14.07‰，差值达2.51‰，平均为12.84‰；鱼鳃δ^15N值范围10.41‰-12.10‰，差值达1.69‰，平均为11.41‰；内脏团δ^15N值范围10.09‰-11.98‰，差值达1.89‰，平均为11.08‰；鱼鳞δ^15N值范围10.10‰-11.35‰，差值达1.25‰，平均为10.66‰。鱼肉、鱼鳃、内脏团、鱼鳞的δ^15N值大小依次为：鱼肉、鱼鳃、内脏团、鱼鳞。由δ^15N值推算出来金线鱼的营养级范围为2.46～3.12，平均值为2.80，符合其主要摄食浮游和底栖动物的食性。

To study Sardinella clupeoides in Naozhou Bay by stable isotope analysis method, 10 fishes were sampled and analyzed to know their stable isotope values and trophic levels. The muscle, gills, visceral mass and scale of Sardinella clupeoides were tested by Stable Isotope Ratio Mass Spectrograph. The results showed that their δ^15N values were 10.09‰ - 14.07‰ and the span was 3.98‰, and δ^15N values of the muscle, gills, visceral mass and scale were 11.56‰-14.07‰, 10.41‰-12.10‰, 10.09‰-11.98‰, 10.10‰ - 11.35‰, respectively. The averaged δ^15N values of these 4 tissues were 12.84‰, 11.41‰, 11.08‰, 10.66‰which lined as follows, muscle〉gills〉visceral mass〉scale. Trophic levels were calculated byδ^15N values of the muscle. The results show that the trophic level, with the average level of 2.80, ranges from 2.46 to 3.12 which match with their feeding habit of phytoplankton and benthic animals.