Sea Anchovy Basic Food Web Organisms Three Elements Of Carbon, Nitrogen And Phosphorus Composition And Fatty Acid Composition Characteristics

C, N, P and fatty acids compositions were determined in major biology of food webs based on anchovy(Engraulis japonicus) including phytoplankton, zooplankton, Engraulis japonicus and other fishes such as Scomberomoms niphonius, Pseudosciaena polyactis in Yellow Sea. Carbon and nitrogen were analysed by Elemental Analyzer (Vario EL III). Phosphorus was determined by Inductive Coupled Plasma -Atomic Emission Spectrometry(ICP-AES). Fatty acids analysis was under taken by Gas Chromatogram instrument (Varian3800) .Total percent of carbon, nitrogen and phosphorus in Engraulis japonicus varied from 46.3% to 60.5%. And carbon content of Engraulis Japonicus was increasing and phosphorus was decreasing when growing from larvae to adult. However, there was not significant difference to nitrogen in different stages. Differences of nutrient contents in different life stages may be caused by changes in allocation of materials for growth within the body. So consequencetly difference in age structure of Engraulis japonicus populations would lead to change its element compositions. Since Engraulis japonicus was one of the most important diet to high trophic fishes such as Scomberomorus niphonius and Trichiurus lepturus, Unbalance of supplying elements of potential diets would directly lead to the facts that some fish species would grow slower and smaller. Moreover, according to element compositions in mussels, these fishes were divided into three groups. The first group was characteristic with low phosphorus and high C/N ratio including Engraulis japonicus, Conger myriaster and Scomberomorus niphonius. The second had low phosphorus and low C/N ratio including fishes such as lower and middle carnivores such as Pseudosciaena polyactis, Platycephalus indicus and Argyrosomus argentatus. The third included some cold temperatefishes such as Scomberomorus niphonius and Liparis tanakae that were high phosphorus and low C/N ratio.There was significant difference between larvae and adult for Engraulis japonicus in fatty acid compositions, and there was significant relation between some fatty acids(18:3n3, 22:6n3, 22:5n3 and 22:5n6 ) content and length. According to 16:1n7/20:3n3 to 22:6n3/20:5n3, 18:3n3 to 16:1n7/20:3n3, Engraulis japonicus was divided into three groups-Engraulis japonicus larve, total length less than 100 millimeter and total length more than 100 millimeter. The biggish difference of diet composition in different stage to Engraulis japonicus may be the primary reason that lead to difference of fatty acid composition among different stages. At the same time lipid chass( the ratio between triacyglycerides and phospholipids) also influenced fatty acid composition.There was obvious difference among different trophic biology. Because contents of 16:1n7 and 18:1n7 was originate from phytoplankton and 18:1n9 reflected animaldietary input, with trophic level increasing, fishes dietary turn from zooplanktons to swim animals would lead to decreasing of 16:1n7 originated from phytoplankton and increasing of 18:1n9. So we think that monounsaturated fatty acids are potential biomarkers for analysing tropic relation among biology. Moreover, fatty acid composition also indicated environment change. For example, cold temperatefishes such as Liparis tanakae and Hexagrammos otakii had more polyunsaturated fatty acids than warm species such as Pseudosciaena polyactis, Trichiurus lepturus and Scomberomorus niphonius.