1295 / 2024-09-20 23:23:17

The Hulong hybrid grouper (Epinephelus fuscoguttatus♀×Epinephelus lanceolatus♂) had invaded and caused negative ecological impacts

Hulong hybrid grouper; biological invasion;,diet composition;,stable isotope features;,Food web modeling

Session 22 - Impacts of climate change and human activity on ocean food production

    Nowadays, various types of hybrid groupers have been successfully applied in the mariculture industry in the southwest Pacific coastal area, raising public concern about potential biological invasions. As the earliest produced hybrid grouper with the highest yield worldwide, the Hulong hybrid grouper (Epinephelus fuscoguttatus♀×Epinephelus lanceolatus♂, also known as the Sabah grouper) was first produced in Malaysia in 2007 and subsequently developed in mainland China in 2009. With the development of the breeding and mariculture industry of the Hulong hybrid grouper on Hainan Island, escapees have been sighted in the coastal waters of Hainan Island for years. Their current distribution includes all the coastal waters of Hainan Island, with a preference for inshore reef and artificial structure areas. Based on social investigations and specimen collections, this species has been continuously present for at least 12 years in multiple locations. The growth and gonadal development status of this hybrid grouper indicate the long-term survival and population establishment of the Hulong hybrid grouper in the wild. The mechanisms of their introduction include unintentional escapees from the aquaculture industry as well as intentional releases. The negative ecological impacts of the Hulong hybrid grouper were further discussed by determine its diet composition, stable isotope features and dynamic scenarios in tropical ecosystem. The hulong hybrid grouper had a diverse diet and exhibits a significantly different diet composition, indicating a diet transitioning and acquiring new feeding behavior. Further, it appears that hulong hybrid grouper resource use overlaps substantially with other similarly sized sympatric mesopredators, in particularly with fish in genus Epinephelus, Cephalopholis and Cheilinus. Our modeling exercise suggests that hulong hybrid grouper have a strong impact on the magnitude of biomasses and fluxes in coral reef food webs of coastal region of Hainan Island. The model suggests that hulong hybrid grouper can impact the ecosystem in different ways:  releasing competition and producing greater predation mortality among species, and producing direct competition for fish resources.