Seasonal variations in the lipid and fatty acid composition of the euphausiid Meganyctiphanes norvegica from the Ligurian Sea

• Published in: Marine Ecology Progress Series
• Main Authors: Mayzaud, P, Virtue, P, Albessard, E
• Format: Article in Journal/Newspaper
• Language: English
• Published: Inter-Research 1999
• Subjects: Biological Sciences; Ecology; Marine and Estuarine Ecology (incl. Marine Ichthyology); Meganyctiphanes norvegica; Northern krill
• Online Access: https://doi.org/10.3354/meps186199; http://ecite.utas.edu.au/102500

Lipid and fatty acid composition of the northern krill Meganyctiphanes norvegica from the Mediterranean Sea were studied with respect to sex and season. Detailed composition of the lipid classes is reported for both males and femalesduring the spring reproductive season and the late summer non-reproductive season. Both sexes showed similar lipid structure, with neutral lipids dominated by triacylglycerols. Polar lipids were dominated by phosphatidylcholine. Fatty acid compositions ofboth polar lipids and triacylglycerols showed little change with sex or season. Polar lipids were dominated by HUFA (20:5n-3 or EPA and 22:6n-3 or DHA) as well as palmitic and oleic acid. Neutral lipid fatty acid profiles were dominated by 22:6(n-3) andpalmitic acid, with a significant contribution of oleic, myristic, stearic and vaccenic acids as well as 20:5(n-3). Seasonal changes in total lipids showed maximum accumulation in early summer and minimum levels in early winter. Changes in fatty acidcomposition appeared related to the succession of populations with varying levels of triacylglycerols, as illustrated by the contrast between the early winter and spring periods in a correspondence analysis. Increased proportions of myristic, palmitoleicand 18:4(n-3) acids during the spring period are characteristic of the triglyceride fraction while the main descriptor of the winter period is DHA, which is the key constituent of the polar lipids. Comparison with literature data illustrated the cleardecrease in lipid content of northern krill with latitude and the specific nature of the seasonal pattern recorded in the Ligurian Sea. The regional variability in fatty acid composition and the significance of fatty acids as potential markers of feedingbehaviour are discussed in relation to the omnivorous character of M. norvegica .