Herbivorous fish feeding dynamics and energy expenditure on a coral reef: Insights from stereo‐video and AI‐driven 3D tracking

Unveiling the intricate relationships between animal movement ecology, feeding behavior, and internal energy budgeting is crucial for a comprehensive understanding of ecosystem functioning, especially on coral reefs under significant anthropogenic stress. Here, herbivorous fishes play a vital role as mediators between algae growth and coral recruitment. Our research examines the feeding preferences, bite rates, inter‐bite distances, and foraging energy expenditure of the Brown surgeonfish (Acanthurus nigrofuscus) and the Yellowtail tang (Zebrasoma xanthurum) within the fish community on a Red Sea coral reef. To this end, we used advanced methods such as remote underwater stereo‐video, AI‐driven object recognition, species classification, and 3D tracking. Despite their comparatively low biomass, the two surgeonfish species significantly influence grazing pressure on the studied coral reef. A. nigrofuscus exhibits specialized feeding preferences and Z. xanthurum a more generalist approach, highlighting niche differentiation and their importance in maintaining reef ecosystem balance. Despite these differences in their foraging strategies, on a population level, both species achieve a similar level of energy efficiency. This study highlights the transformative potential of cutting‐edge technologies in revealing the functional feeding traits and energy utilization of keystone species. It facilitates the detailed mapping of energy seascapes, guiding targeted conservation efforts to enhance ecosystem health and biodiversity. Our research harnesses cutting‐edge technologies, including remote underwater stereo‐video and AI‐driven multi‐object tracking, to measure functional traits and the rates of energy expenditure of key grazing fish species on coral reefs. By doing so, we uncover the substantial influence of species like the Brown surgeonfish and Yellowtail tang on herbivore feeding dynamics, despite their comparatively low biomass. The potential of our approach lies in its ability to derive energy seascapes and novel ecosystem health indicators, offering a sophisticated toolset for enhancing conservation strategies and understanding the intricate balance of marine ecosystems.