*Article* **DNA Barcoding Is a Useful Tool for the Identification of the Family** *Scaridae* **in Hainan**

**Bo Liu 1,2, Yali Yan 1, Nan Zhang 1,3, Huayang Guo 1,3, Baosuo Liu 1,3, Jingwen Yang 1, Kecheng Zhu 1,3 and Dianchang Zhang 1,3,4,5,\***


**Abstract:** Species markers can be quickly and accurately assessed using DNA barcoding. We investigated samples from the parrotfish family *Scaridae* using DNA barcoding in Hainan. A total of 401 DNA barcodes were analyzed, including 51 new barcodes generated from fresh material, based on a 533 bp fragment of the cytochrome c oxidase subunit I (*CO* I) gene. There were 350 *CO* I barcode clusters that matched 43 species from the Barcode of Life Data Systems (BOLD) and GenBank databases. The results showed the following average nucleotide compositions for the complete dataset: adenine (A, 22.7%), thymine (T, 29.5%), cytosine (C, 29.5%), and guanine (G, 18.2%). The mean genetic distance between confamilial species was nearly 53-fold greater than that between individuals within the species. In the neighbor-joining tree of *CO* I sequences, *Chlorurus sordidus* and *C. spilurus* clustered together, and all other individuals clustered by species. Our results indicated that DNA barcoding could be used as an effective molecular tool for monitoring, protecting, and managing fisheries, and for elucidating taxonomic problem areas that require further investigation.

**Keywords:** *Scaridae*; DNA barcoding; cytochrome c oxidase subunit I (*CO* I)
