Seasonal changes in the biochemical components of Pseudonereis anomala (Polychaeta, Nereididae) from the Alexandria coast, Egypt

The biochemical composition (carbohydrates, protein, lipids, fatty acids and amino acids) of the nereid polychaete Pseudonereis anomala Gravier 1901, from a shallow part of the Alexandria coast (Egypt), was studied seasonally. The results revealed that P. anomala had a lower water content, higher carbohydrates and protein, but approximately similar or higher lipid levels than several other polychaetes. Fatty acids appeared to be dominated by unsaturated acids, constituting seasonally 49.6-81%, while saturated acids reached high amounts in winter and spring (23.3 and 38.3% respectively). C20:5n-3 was the major polyunsaturated fatty acid, accompanied by small amounts of C18:4n-3, C20:4n-6, C16:1n-7 and C20:1n-9. C18:0 dominated the saturated fatty acids for most of the year, except in autumn when C16:0 was the major one.