Molly-Mae Baker (PhD candidate at the University of Western Australia, School of Biological Sciences & Oceans Institute, and the Australian Institute of Marine Science).

When we dive or snorkel on tropical coral reefs, our attention is often drawn to the striking bommies, the sprawling layers of coral plates, or the delicate networks of branching staghorn corals. Yet, in our fascination with these grand structures, we often overlook the tiny baby corals that exist in the spaces in between. This is also true in the scientific literature on corals, where demographic data for the early life stages of corals is scarce, despite their success playing a significant role in population maintenance and recovery following disturbances. For example, we know very little of how tiny (millimetre) coral larvae select suitable habitats for settlement and how bio-physical variables influence their growth and survival as they settle, metamorphose, and attach to the seafloor for the rest of their lives.

Low rates of growth and survival in coral recruits is one of the biggest bottlenecks to population growth. This has important implications for the potential success of management and restoration activities proposed to aid coral reefs in the future, many of which target the early life stages of corals. My PhD research uses a combination of modelling and field studies to unravel the influence of bio-physical variables on coral larval settlement, growth, and survival to help overcome this bottleneck and increase post-recruitment survival.

As part of this, I embarked on a field trip to the world’s largest fringing reef and World Heritage Site, Ningaloo Reef. With the help of the Reef Song team from the Australian Institute of Marine Science, I found and tagged hundreds of tiny coral recruits across the stunning stretch of coastline south of Coral Bay. I also conducted benthic community surveys and photogrammetry (to produce 3D reef models and get estimates of topographic complexity) at multiple spatial scales surrounding each recruit. Not only will this indicate where coral larvae like to settle but will also allow us to explore how settlement location influences post-settlement success.

With the help of an Ecological Society of Australia (ESA) ‘Student Research Award’ I recently resurveyed tagged coral recruits to obtain annual growth and survival data. I am now in the process of analysing this data to determine optimal habitats for the growth and survival, as well as the spatial scales at which the surrounding benthic community composition and habitat complexity are most important to recruit success. This will help to inform management and restoration interventions (such as larval seeding) across multiple scales, ranging from the sites for deployments through to types of artificial substrata that may maximise post-recruitment growth and survival. Moreover, the demographic data collected as part of this study will be a valuable addition to the literature aiding all those working in coral reef modelling and management.

A massive thank you to the ESA, the University of Western Australia, and the Australian Coral Reef Resilience Initiative (co-funded by the Australian Institute of Marine Science and BHP) for supporting my research. I am extremely grateful to have had the opportunity to travel to such a beautiful part of the world and to work with such complex and fascinating organisms. I look forward to sharing more of my results as I continue to analyse this new data. I acknowledge the Baiyungu, Thalanyji and Yinikurtura People as the Traditional Owners of the Nyinggulu Coast. I pay my respects to these First Nations people, their Elders past, present, and emerging and acknowledge their continuing spiritual connection to their land and Sea Country.