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

Abstract

Anthropogenic activities, such as non-native aquaculture species introduction have been considerably altering trophic interactions in marine ecosystems. The hybrid grouper (TGGG), an aquaculture product originated from artificial F1 crossbreed between Epinephelus fuscoguttatus and E. lanceolatus, have been released in the wild through religious activities, raising concerns about this man-made introduced species. The carnivorous diet, together with large body size inherited from the parental species have made TGGG a candidate that could pose significant impacts to the marine ecosystem. Yet, little is known about the diet composition of TGGG upon release into the natural environment, and any dietary overlap or partition with closely related endemic species. Here, we deploy gut content DNA metabarcoding to determine the prey richness and dietary niche of wild caught TGGG and compare with four native grouper species (Epinephelus awoara, E. bleekeri, E. coioides and E. quoyanus). The TGGG exhibited six unique prey taxa with teleosts being the major taxa preyed upon followed by crustaceans and cephalopods and displayed significant lower mean number of pray taxa compared to other groupers. The TGGG exhibits a significantly different diet composition, possibly indicating a diet transitioning and acquiring new feeding behavior. This study provides a comprehensive analysis with high taxonomic resolution on the diet of artificial hybrids in the wild, suggesting possibility of introduction success if release events persist. Finally, these findings provide new information on how local trophic dynamics are impacted by under-investigated release of animals through religious practices.