Release of hybrid grouper threatens Hong Kong’s coastal areas

Ecologists from the School of Biological Sciences (SBS) and the Swire Institute of Marine Science (SWIMS) at the University of Hong Kong (HKU) identified unique ecological risks associated with grouper stocking in the region. Hong Kong’s coastal areas are associated with the practice of releasing animals, according to Phys.org. Their research highlights how the tiger grouper-turmeric grouper hybrid, also known as the Sabah grouper, disrupts local marine ecosystems by exploiting a distinct ecological niche and has the potential to become become a dominant carnivore.

This is the first study to use the DNA family tree method to analyze the diet of this hybrid species, thereby highlighting the urgent need for public education and conservation measures to minimize biological impacts. unwanted behavior. The research results are published in the journal Reviews in Fish Biology and Fisheries.

TGGG is a hybrid species bred through aquaculture by crossing tiger grouper fish (Epinephelus fuscoguttatus) with turmeric grouper (Epinephelus lanceolatus). Highly valuable thanks to its large size and fast growth, this fish is very popular in Hong Kong seafood markets. Its affordable price and impressive size also make it a favorite choice for local releases. However, this action entails many serious ecological consequences.

To explore the potential ecological impact of releasing hybrid grouper in coastal areas of Hong Kong, the research team used a DNA family tree to analyze the diet of TGGG. In the first project to apply this method to study the feeding habits of hybrid groupers, researchers retrieved and sequenced DNA from their stomach contents, allowing them to identify prey, even if the prey is partially or completely digested. Such an approach provides a detailed and accurate picture of the hybrid grouper’s feeding habits and interactions with the local marine ecosystem.

According to research, TGGG is a formidable predator with a unique diet, specializing in hunting many prey that native species do not consume such as fish, crustaceans and cephalopods. By exploiting wide ecological niches and gaps in ecosystems where resources are underutilized, TGGG disrupt local food webs and can thrive as dominant carnivores.

Researchers warn that the rapid growth, large size and lack of natural predators in Hong Kong waters will turn hybrid groupers into extremely competitive species. Those characteristics will become a major threat to the balance of ecological diversity in Hong Kong’s coastal area. The study also draws attention to the role of release practices in introducing non-native species such as TGGG to the sea.