Distinct resource utilization by introduced man-made grouper hybrid: an overlooked anthropogenic impact from a longstanding religious practice

Abstract

Anthropogenic activities, such as the introduction of non-native aquaculture species, have significantly altered trophic interactions in marine ecosystems. The hybrid grouper (TGGG), an aquaculture product originating from an artificial F1 crossbreed between Epinephelus fuscoguttatus and E. lanceolatus, has been released into the wild through religious activities, raising concerns about the ecological implications of this man-made species. With its carnivorous diet and large body size inherited from the parental species, TGGG could pose significant impacts to the marine ecosystem. Yet, little is known about the diet composition of TGGG upon release into the natural environment as well as its dietary overlap or partitioning with closely related species. Here, we deployed gut content DNA metabarcoding to determine the prey richness and dietary niche of wild-caught TGGG and compared it to four native grouper species (Epinephelus awoara, E. bleekeri, E. coioides and E. quoyanus). Our results indicate that the TGGG exhibited five unique prey taxa, with teleosts being the predominant prey, followed by crustaceans and cephalopods. Notably, the TGGG displayed a significantly lower mean number of prey taxa compared to the other groupers, suggesting a distinct diet composition that may reflect a transition in feeding behaviour. This study provides a comprehensive analysis with high taxonomic resolution on the diet of artificial hybrids in the wild, indicating the potential for successful establishment if release events persist. Finally, these findings provide new insights into how local trophic dynamics are impacted by the under-investigated release of animals through religious practices.