Chemometric Discrimination among Wild and Cultured Age-0 Largemouth Bass, Black Crappies, and White Crappies Based on Fatty Acid Composition

Abstract

The potential to distinguish juvenile wild from cultured fishes and to discriminate among juvenile fishes by species based on fatty acid composition was demonstrated. Statistical approaches to data evaluation included analysis of variance, correlation analysis, principal component analysis (PCA), and quadratic discriminant analysis (QDA). Differences were determined between wild and cultured fishes both within and between species and between hatcheries. Fatty acid compositions were compared among individual (not composited) specimens of wild and cultured, age-0, freshwater species: largemouth bass Micropterus salmoides, black crappies Pomoxis nigromaculatus, white crappies P. annularis, and black-nose crappies. Four fatty acids were investigated: linoleic acid (18:2n-6), linolenic acid (18:3n-3), arachidonic acid (20:4n-6), and docosahexaenoic acid (22:6n-3). Linoleic acid was the primary fatty acid used to differentiate juvenile wild from cultured fishes. Concentrations of linoleic acid were significantly different (p < 0.05) in cultured largemouth bass and black crappies from the wild counterparts. Linolenic acid concentrations were not significantly different (p < 0.05) between wild and cultured largemouth bass but were significantly different between wild and cultured black crappies. Wild largemouth bass contained higher concentrations of arachidonic acid than the cultured bass, and concentrations of docosahexaenoic acid were twice as high in wild black crappies than cultured black crappies. On the basis of four signature fatty acids, 90 of 91 juvenile fishes were correctly classified as wild or cultured; 32 of 37 wild juvenile fishes originating from the same reservoir were differentiated by species. Data from the training set were used to classify a test set of fishes as to species, source, or origin with 100% accuracy.