Pristane and other hydrocarbons in some freshwater and marine fish oils.

Pristane levels in four commercial freshwater fish oils (alewife, tullibee, maria and sheepshead) were found to be markedly lower (0.0001% or less) than those in marine fish oils (herring, sand launce, cod liver and gray cod liver) selected for comparison on the basis of similar types of depot fat storage (0.008-0.107%). Certain normal alkanes were also identified by gas chromatography. Of these, heptadecane was predominant in all of the freshwater fish oils, but octadecane was more prevalent than heptadecane in three of the marine oils.