A novel catfish cultured in South China is proved to be Silurus asotus based on morphological and molecular genomic identification

Abstract

One novel catfish (Chinese called it ‘Gou nian’) widely cultured in China shares the same name with Ictalurus punctatus introduced from America, but is morphologically closed to genus Silurus. For years, the novel catfish was speculated to be an artificial hybrid of S. asotus and S. meridionalis. Therefore, we investigated the correct taxonomic status and origin of the novel catfish by means of morphological and molecular approaches. First, the novel ‘Gou nian’ could not be distinguished from S. asotus and S. meridionalis through anatomical observation, however, it was morphologically similar to S. asotus. Then, the novel ‘Gou nian’ was found not a hybrid of S. asotus and S. meridionalis based on the identification of ITS-2 and RAG-2, moreover, the analysis of COI barcoding found it more likely to be S. asotus. The phylogenic and population genetic analysis of Cyt b showed that the novel ‘Gou nian’ belonged to a taxonomic branch of S. asotus from the Liao River. The results convincingly indicated that the novel catfish is S. asotus and may originate from Northern China. The findings also provided useful implications for aquaculture management of the species.

Keywords

• Species identification
• Morphometrics
• Nuclear genes
• DNA barcode
• Population genetics
• Catfish