Species identification of snapper: A food poisoning incident in Taiwan

A snapper (Lutjanidae fish) is a carnivorous coral reef fish that is distributed in sea areas around Taiwan. In December 2008 in southern Taiwan, a food poisoning incident occurred due to the ingestion of snapper, and the causative residue of ciguatera was investigated using a toxicity assay. To identify the species of the causative sample, six suspected species of Lutjanidae fish commonly found in Taiwan were analyzed using both sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques. According to the low molecular weight region (<30.0 kD) of species-specific patterns extracted from myofibrillar and sarcoplasmic proteins, the 6 snapper species could be clearly differentiated by the SDS-PAGE method. Furthermore, a consistent 465 bp sequence of the mitochondrial cytochrome b gene from the 6 snapper species was amplified by the PCR method and was rapidly distinguished by the analysis of restriction enzymes. According to both SDS-PAGE and PCR-RFLP methods, the poisonous sample was identified as Lutjanus bohar, which is also a notorious Lutjanidae species containing ciguateric toxins.