Freshwater Fish Oils: Yields and Composition of Oils from Reduction of Sheepshead, Tullibee, Maria, and Alewife

Abstract

Oils were produced from four species of freshwater fish (sheepshead, Aplodinotus grunniens; tullibee, Coregonus artedii; maria, Lota lota; alewife, Alosa pseudoharengus) in a commercial reduction plant. The oil iodine values were, respectively, 123, 143, 158, and 165. Fatty acids were determined by gas–liquid chromatography. All four oils showed higher levels of C₁₆ and C₁₈ fatty acids than corresponding marine oils, but only sheepshead and tullibee had distinctly low levels of C₂₂ acids. The four freshwater oils differed from most marine oils in having higher proportions of linoleic, linolenic, and arachidonic acids. In most respects fatty acid compositions of freshwater fish oils were not dissimilar from marine oils.