). Average total lipid content was determined as percentage (%) and per individual (mg ind -1 ). It was proportionally highest in February (7.03%) and lowest in September (3.02%). However, average lipid content per individual was highest in February (0.11 mg ind -1 ) and lowest in September and November (0.04 mg ind -1 ). Major fatty acids in C. euxinus were identified as 16:0, 16:1 n-7, EPA and DHA. ∑SFA, ∑MUFA, ∑PUFA and ∑HUFA were observed to be correlated with temperature. ∑SFA and ∑MUFA increased with the rise in temperature (r 2 =0.74, r 2 =0.73, p<0.05, respectively) whereas ∑PUFA and ∑HUFA increased as temperature decreased (r 2 =-0.73, r 2 =-0.80, respectively, p<0.05). Additionally, while ∑PUFA and ∑HUFA increased (r 2 =0.61, r 2 =-0.68, respectively, p<0.05), ∑MUFA decreased (r 2 =-0.68, p<0.05) as chlorophyll-a increased. It was observed that the degree of unsaturation increased as temperature decreased. Results of the study revealed that C. euxinus has rich lipid content as well as fatty acid composition and it plays an important role in the South-eastern Black Sea ecosystem functionalities especially having key role in energy fluxes to higher trophic levels.