关键词: 氮矿化, 施肥, 铲草, 氮淋溶, 降香黄檀, 印度檀香

Abstract: Argentine hake (Merluccius hubbsi), one of the important fish species with highly commercial value, is the target species for bottom trawl fishery in southeastern Atlantic Ocean. In this study, gas chromatography-mass spectrometry (GC-MS) was used to measure the fatty acid composition of Argentine hake. We examined the potential difference of each fatty acid composition, including saturated fatty acids (SFA), mono-unsaturated fatty acid (MUFA) and poly unsaturated fatty acid (PUFA) across different standard lengths, months and latitudes. The results showed that the contents of different types of fatty acids was in order of ∑PUFA>∑SFA>∑MUFA. Specific fatty acids with higher levels included C22:6n3 (docosahexaenoic acid, DHA), C16:0, C18:1n9c, C20:5n3 (eicosapentaenoic acid, EPA) and C18:0. Among them, DHA had the highest content, accounting for 35.27% of total amount of fatty acids. The high ratio of PUFA/SFA suggested that Argentine hake can be considered as the supplementary material for PUFA. Across different standard length classes, higher contents of ∑SFA and ∑PUFA were found in small standard length class (20.1-30.0 cm), where DHA and EPA in ∑PUFA were relatively higher, making n-3/n-6 enlarged, indicating that smaller individuals were more nutritious than larger ones. Except for n-3/n-6, there was no significant difference of the content of fatty acids across months. The highest n-3/n-6 ratio was found in January, indicating that muscle tissue of Argentine hake had higher nutrition in this month. There was no significant difference in contents of each fatty acid across different latitudes and sea surface temperatures.

Key words: Santalum album, weeding, Dalbergia odorifera, nitrogen mineralization, fertilization, nitrogen leaching