Metabarcoding analysis of potential HABs in the Maowei Sea, China: A baseline information for the “Pinglu Canal Waterway” mega-waterway project

Abstract

Maowei Sea is one of the cleanest sea areas in China, with relatively little anthropogenic activity. The Maowei Sea is rich in biodiversity and is the largest natural ground for the Hong Kong oyster Crassostrea hongkongensis seed collection. In recent years, the Chinese government has launched a mega project called “Pinglu Canal Waterway”, which will connect the main river system to the Maowei Sea. This project is expected to alter the physical and chemical properties of the Maowei Sea and affect the structure of the phytoplankton community. This study was conducted to screen potential harmful algal bloom species (HABs) in Maowei Sea using metabarcoding technique. In general, nine potential HABs were identified, including six toxin producers (Chattonella spp., Heterosigma akashiwo, Heterocapsa rotundata, Heterocapsa pygmaea, Karenia mikimotoi and Karlodinium veneficum) and three non-toxin producers (Gymnodinium impudicum, Skeletonema costatum and Ulva prolifera). The occurrence and relative abundance of these potential HABs increases with increasing water salinity. The findings of this study not only provide information on the occurrence of potential HABs in Maowei Sea, but also provide valuable information that contributes to the development of aquaculture and fishery management plans to be implemented in Maowei Sea.