Chemometric analyses of fatty acids in sauger, white bass, and paddlefish from the Ohio River as indicators of species, season, and subpopulations

The aquatic environment affects fatty acids (FAs) in fishes. Using gas chromatography (GC-FID) and gas chromatography mass spectrometry (GC-MS) in electron impact (EI) and chemical ionization (CI) modes over 90% of the FAMEs extracted from white muscle of freshwater fish have been identified and constitute 13 FAs. Chemometric analyses of FAs from sauger (Stizostedion canadense ), white bass (Morone chrysops) and paddlefish ( Polydon spathula) from the Ohio River have indicated that species, season, and location can significantly affect FA profiles. Sauger and white bass were similar in percent lipid and contained a significantly lower percent of lipids than paddlefish. A positive correlation with sampling date from June to October existed in sauger and white bass for saturated FAs and n-6 FAs, while a negative correlation existed for monounsaturated FAs and the ratios of n-3/n-6, eicosapentaenoic acid/arachidonic acid (EPA/AA), and docosahexaenoic acid/arachidonic acid (DHA/AA). River mile was positively correlated with 14:0, 16:1n-7, and 18:3n-3 in both sauger and white bass. FA data indicated that sauger and white bass were divided into upper and lower subpopulations at approximately Ohio River mile 341.0. The upper Ohio River subpopulation of sauger and white bass contained more polyunsaturated FAs, n-6 FAs, and 22:5n-6, less monounsaturated FAs, 14:0, 16:1n-7, 18:1n-7, 18:3n-3, and lower ratios of 20:5n-3/20:4n-6, and 18:3n-3/18:2n-6 than the lower Ohio River subpopulation. Relative weight, Wr, an indicator of fish health and condition, was significantly higher in sauger from the lower Ohio River subpopulation. Findings indicate that FAs do provide information about aquatic environments, support future research using fatty acids as biomarkers, and provide information useful for studying fish fitness in Ohio River species.