Identification of commercial fish species belonging to the orders pleuronectiformes and gadiformes: library of isoelectric focusing patterns.

Isoelectric focusing in polyacrylamide gel was used to establish an identification archive of fish species belonging to the orders Pleuronectiformes, or flat fish, and Gadiformes, or gadoid fish. The 2 orders include species of different commercial value and interest that are frequently requested in European fish markets, but are susceptible to substitution either because they are morphologically similar or because they arrive on the markets already filleted or sliced. The sarcoplasmic protein profiles are species-specific and reproducible. The use of densitometry and image analysis coupled with a simple computer program overcomes the subjective evaluation of the patterns, making it possible to identify species correctly.