Differentiating the wild or farmed origin of Mediterranean fish: a review of tools for sea bream and sea bass



Pablo Arechavala-Lopez, Department of Marine Sciences and Applied Biology, University of Alicante, PO Box 99, 03080, Alicante, Spain. Email: pablo.arechavala@ua.es


Based on the fact that farmed fish experience different environments, stocking densities and feeding regimes compared with wild fish, several techniques have been developed to discriminate the wild or farmed origin of fish. These techniques quantify differences between genetics, chemical characteristics, fatty acid compositions, trace elements, pollutants, stable isotopes, morphology and organoleptic characteristics. Gilthead sea bream and European sea bass are the most important marine fish in Mediterranean aquaculture and are highly appreciated by commercial and recreational fisheries. A total of 60 studies that used techniques to discriminate farmed from wild fish for sea bream and sea bass form the basis of this review. The most common technique used differences in the lipid and fatty acid composition of fish. Many of these studies dealt with food science and product quality, rather than tracing escapees. A wide range of identification tools is useful in determining the correct origin of captures and proper labelling of marketed fish. External appearance and morphometry are useful for rapid assessments and can be achieved with high accuracy and little cost, especially for sea bream. This makes these methods suitable for detecting large and recent escape events, applicable in fisheries studies, and for ensuring that wild and farmed fish are separated in the marketplace. Techniques using differences in chemical or genetic composition are more useful for environmental monitoring, as they have higher accuracy and can detect escapees long after the escape incident. Regulatory bodies should legislate protocols that describe the technique(s) that must be applied in specific circumstances.