ZAC7 Abstracts – Session 2

This presentation provides an overview of ZMT’s current research activities across the Indo-Pacific region, highlighting collaborative projects, key findings, and emerging research directions. We present a synthesis of ongoing work spanning multiple program areas, from ecological monitoring to social-ecological systems research. The review identifies synergies between different research streams and discusses opportunities for enhanced integration and impact. This stocktaking exercise helps chart future research priorities and strengthens regional research networks.

Reefs affected by sediment run-off and logging-driven turbidity remain among the least quantified coastal ecosystems in the Pacific. While turbidity alters both benthic structure and trophic dynamics, baseline data on habitat zonation and functional stress responses on reef tidal flats are still scarce. This contribution presents results from a month-long field campaign on Kolombangara Island (Western Province, Solomon Islands, 2023), addressing how light attenuation and sediment load influence reef-fish energetics and reef-flat habitat structure. Using stereo-video recordings, we tracked the fine-scale movements of three butterflyfish species (Chaetodon baronessa, C. lunulatus, C. vagabundus), a detritivore (Ctenochaetus striatus), and a scraping herbivore (Chlorurus bleekeri) across a natural turbidity gradient. Unsupervised 3D Behavioural Change-Point Analysis (BCPA) segmented continuous trajectories into foraging, transit, and station-holding states, while Overall Dynamic Body Acceleration (ODBA) provided an index of energetic cost. Coral-feeding specialists displayed increased energy expenditure and altered movement dynamics under reduced visibility, contrasting with the behavioural stability of detritivores and generalists. In parallel, a drone–snorkeller mapping workflow generated the first metre-scale habitat maps of the southern reef flat. The resulting zonation revealed a narrow coral crest, a midflat dominated by Sargassum, and extensive Thalassia hemprichii seagrass meadows shoreward. AI-assisted classification (ReefCloud.AI) aligned well with manual annotations for dominant habitat types, demonstrating that low-cost drone imagery can yield robust baselines for future community-based monitoring. Together, these complementary datasets delineate emerging Energy Seascapes that link water clarity, energy demand, and habitat composition. The approach highlights how behavioural energetics and spatial mapping can jointly expose early functional shifts and underpin a co-designed monitoring framework now being developed with partners in Vavanga village.

Feed limitation is a major constraint in lobster aquaculture, particularly in Indonesia, where farmers rely on nutritionally inconsistent trash fish that are seasonally variable and compete with human consumption. Sustainable, locally producible alternatives are therefore needed. Earthworms represent a promising option due to their high-quality protein, favorable amino acid profile, and potential for low-cost cultivation. This study evaluated the effects of fresh earthworm-based diets on juvenile Panulirus homarus under laboratory and field conditions. In controlled laboratory trials, partial or complete replacement of trash fish with earthworms significantly improved growth, survival, and immune parameters. When tested in floating net cages under natural conditions, earthworm-fed lobsters performed similarly to those fed trash fish, highlighting practical challenges in feed delivery at farm scale. These findings indicate that earthworms are nutritionally suitable and effective under controlled conditions, but their successful use in real-world aquaculture depends on optimizing feed administration. With appropriate delivery methods, earthworms could provide a sustainable alternative to trash fish, supporting improved growth, survival, and overall productivity in Indonesian lobster aquaculture.