DNA barcoding for the identification of shark lips (??): A nationwide survey for analyzing a never investigated product in the Chinese market

A nationwide survey conducted in China aimed at authenticating species in shark lips products (??) (n = 252) by full DNACOI barcoding (FDB; 652 bp) is presented. In addition, the efficiency of the FDB and of the mini DNA barcode (MDB; 127 bp) proposed by Fields et al. (2015) (PloS one, 10, e0114844.) in identifying the shark species detected in this study was compared. Despite the manufacturing process, the total DNA of the samples presented a medium low fragmentation degree, and the FDB was obtained from almost all the samples except for two (99.2%) from which the MDB was instead successfully obtained. Samples were allocated to species level in 96.4% of the cases. This confirms the importance to perform a preventive evaluation of the level of DNA degradation before selecting cost and time-consuming procedures. Of the 7 identified species, Prionace glauca was the most recovered (65.5%). The other six detected species were Carcharhinus falciformis (11.5%), Sphyrna lewini (6.7%), S. zygaena (3.6%), Isurus oxyrinchus (3.6%), C. longimanus (3.2%) and C. sorrah (2.4%), 5 of which are threatened and 4 are subject to global commerce regulation. Overall, issues in discriminating among some Carcharhinus spp. were highlighted both using the FDB and the MDB. Outcomes of this study confirms the need to improve the Chinese traceability system. In fact, even though a legislation for seafood labelling supported by an official system for name attribution not always ensure the sector safeguarding from frauds, absent or weak traceability system certainly facilitate illegal practices.

Automated summary

A nationwide survey in China used DNA barcoding to authenticate shark lip products, revealing medium-low levels of DNA fragmentation in most samples. The study highlights the need to enhance the traceability system in China, especially to prevent fraudulent practices.