LAUSR

Fish maws (dried swim bladders of fish) have long been used as a medicinal material and valuable tonic food in Southeast Asia. However, it is difficult to identify the original species of fish maws sold on the market due to a lack of taxonomic characteristics. In the present study, thirty-seven kinds of commercial fish maws from various medicinal material markets were examined with sequences successfully obtained from ~95% of the samples. DNA sequencing based on partial sequences of the 16S rRNA gene and COI gene was carried out to investigate the origin of these commercial fish maws. The results indicated that 35 specimens belonged to nine species including five croakers and four non-croakers. All species identification was supported by both high homogeneity (98-100%) and clean cluster with low within-group divergence (0~0.04 for 16S rRNA and 0~0.07 for COI) and high between-group divergence (0.07~0.15 for 16S rRNA and 0.11~0.24 for COI). Croakers were the most predominant species, accounting for 74% of the total fish maw specimens. The large demand for croakers had put some matched species at the risk of extinction because of overfishing. As a valuable food, fish maw has progressively become more popular and it has been used as a substitute of shark fin in banquets. The identification results allowed us to learn more about the fish species available in the fish maw market and provided an indicator for fisheries control of the threatened or endangered fish species. In addition, a probable correlation between the molecular characteristics and morphological features of fish maws was also found. It could provide both consumers and merchants with an important reference for identifying the origin of fish maws.