西南大西洋拉氏南美南极鱼脂肪酸组成及其食性研究

拉氏南美南极鱼Patagonotothen ramsayi为南极鱼科中数量最多、生态地位非常重要的次南极鱼种,为了解拉氏南美南极鱼的营养动力学与生态功能,利用脂肪酸生物标记法探究了该鱼种的脂肪酸组成及其食性。结果表明:从西南大西洋拉氏南美南极鱼肌肉中共检测出16种脂肪酸,其中含量较高的脂肪酸包括C_(16∶0)、C_(18∶1n9)、C_(20∶5n3)(EPA)和C_(22∶6n3)(DHA),DHA平均含量显著高于EPA(P0.05);多种特征脂肪酸含量与体长存在着显著的相关性,饱和脂肪酸、多不饱和脂肪酸和7种脂肪酸含量与体长之间存在着显著的负相关关系(P0.05),而指示摄食对象营养级高低的DHA/EPA值与体长之间存在着显著的正相关关系(P0.05)。研究表明,拉氏南美南极鱼主要摄食浮游生物和底栖生物,其肉食性特性随体长的增大而增强。

Fatty acid composition and feeding habit of rock cod Patagonotothen ramsayi in southwestern Atlantic Ocean

Muscular fatty acid composition and feeding habits were investigated in rock cod Patagonotothen ramsayi as an ecologically important and most abundant sub-Antarctic fish species in the family Notothenioidei in the south-western Atlantic Ocean using fatty acid biomarker analysis to understand the trophic dynamics and ecological func-tion of the rock cod. The results showed that 16 fatty acids were detected in the muscle, higher in C16:0 , C18:1n9 , C20:5n3(EPA) and C22:6n3(DHA). There was significantly higher content of DHA than EPA(P<0. 05). The signifi-cant relationship between content of several types of specific fatty acids and the body length was found, and the contents of saturated fatty acids, polyunsaturated fatty acids and 7 types of fatty acids showed significantly negative correlation with body length( P<0. 05 ) . The ratio of DHA/EPA, which implied the trophic level of food items, however, showed significantly positive correlation with body lengths(P<0. 05). The specific fatty acid analysis re-vealed that the rock cod primarily fed on planktons and benthos, with carnivorous habit transformation with growth.