The sale of escolar (Lepidocybium flavobrunneum) and castor oil fish (Ruvettus pretiosus) is prohibited in Japan, because their muscles are rich in wax which may cause a food poisoning. The identification of these fishes was therefore investigated by wax analysis. The analytical procedure was as follows : lipids were extracted from fish meats, and the presence of wax in the lipids was examined by thin-layer chromatography (TLC). The compositions of these waxes were examined by gas chromatography with FID (FID-GC). In order to investigate the composition of higher alcohols included in the waxes, the lipids separated from fishes were saponified and the extracted unsaponifiable matters were subjected to FID-GC after acetylation. The results obtained from the analysis on 28 fish species showed that the lipids of john dory (Zeus faber) in addition to escolar and castor oil fish contained wax. The gas chromtogram of waxes showed that the molecular formular of waxes of escolar and castor oil fish were C34H66O2, whereas that of john dory was C40H76O2 as their main ingredient. Furthermore, it was shown that the alcohols of escolar and castor oil fish were of C 16 : 0, whereas that of john dory was of C 22 : 1 as their main ingredient. These results indicate that it is possible to distinguish sale-prohibited fishes from edible fishes by wax analysis, even if they are sliced.
