Chemometric analysis of fish fin ray multi-elemental signatures with differentiation of wild and farmed fourfinger threadfin fish

Abstract

Fourfinger threadfin (Eleutheronema tetradactylum) are the commercially important fish along the southern coast of China. The economic value of wild E. tetradactylum was much higher than their farmed counterparts, therefore mislabeling of production methods may lead to premium prices. In the present study, multi-element signatures of fin ray were used to determine the wild caught and pond-cultured E. tetradactylum from southern coast of China. The elemental composition of fish calcified structures was related to the ambient water environment, and could record the water chemistry difference between the aquaculture pond and the natural seawater. Our results demonstrated that multi-element compositions of fish fin rays were significantly different between the wild and cultured fish. Linear discriminant analysis (LDA) and random forest (RF) model correctly discriminated the wild and cultured E. tetradactylum. The classification accuracies of wild and cultured E. tetradactylum were 100% by LDA. The classification accuracies of identifying the source of cultured E. tetradactylum were 95%. However, the fin ray elemental signatures could not differentiate the different wild groups. This strategy provides a promising alternative method to protect against mislabeling of E. tetradactylum.