2.1 Sample collection
A total of 300 specimens of L. spadiceus were obtained from eight
geographic locations, including Beihai (BH), Zhanjiang (ZJ), Leizhou
(LZ), Danzhou (DZ), Dongfang (DF), Maoming (MM), Shanwei (SW), and
Zhangzhou (ZZ) in the South China Sea (Figure 1, Table 1). All L.
spadiceus Specimens were collected from bottom trawl surveys within the
period of April 2022 to April 2023. A morphological analysis was used to
identify species (head, dorsal surface, and ventral surface are covered
with small spines, the dorsal side of the body is brownish-yellow or
yellow-green, caudal fin is white at the upper and lower tips) (Liu et
al., 2016; Chen & Zhang, 2015). Fishes were given access to muscle
tissue, which were then stored in 1.5 ml vials with 95% ethanol at
-20°C until genomic extraction. Experimental procedures concerning fish
were performed following the Experimental Animal Administration
Regulations.