Enhancing coral larvae culture methods and settlement for coral reef restoration

Colleen Rodd

doi:10.25918/thesis.512

Corals have a bi-phasic life cycle, with dispersive larvae that are crucial for maintaining and interconnecting coral populations. However, high mortality during early-life stages creates a critical bottleneck for successful settlement and recruitment. Coral restoration efforts using enhanced larval supply provide pathways to recover degraded reefs, but methods need to be optimised for large-scale outcomes. While coral larvae are generally classified as non-feeding and assumed to be reliant on endogenous maternal lipid stores, previous research has demonstrated that some coral species can supplement these endogenous reserves. Maximising coral larval health is critical for restoration initiatives, yet larval feeding during ex situ culture remains under-explored despite increasing research on optimising rearing protocols. Therefore, the aim of this research was to determine whether supplemental feeding could enhance the efficiency of producing coral settlers for larval-based restoration methods. The research presented in this thesis focused on three key objectives. In Chapter 2, feeding behaviour of coral larvae was established under controlled conditions. The results showed that coral larvae exhibit context-dependent behavioural plasticity, modulating feeding behaviour in response to developmental stage and potential differences in nutritional status. In Chapter 3, the effect of exogenous feeding on settlement success and post-settlement survival was quantified. Feeding larvae with homogenised Artemia more than doubled mean settlement. Using the quantified benefit of feeding described in Chapter 3, an improved feeding protocol was developed in Chapter 4. Experiments used a dose-dependent experimental approach to demonstrate that feeding Acropora larvae moderate amounts of homogenised Artemia during ex situ culture can significantly increase larval size, settlement, and settler size without impacting larval survival. By investigating the role of larval feeding in coral settlement, this work bridges the gap between ecological theory and practical restoration solutions. The findings demonstrate that facultative planktotrophy can provide important advantages in larval size and settlement. Applying these ecological insights to restoration practices highlights the potential for nutritional interventions to improve larval settlement rates and early survival in ex situ larval production, and its potential use in larger-scale larval-based restoration outcomes in the future. By incorporating empirical insights on facultative planktotrophy and larval nutritional requirements into applied restoration protocols, more targeted strategies can be developed to support coral reef resilience in the face of ongoing environmental change.

Enhancing coral larvae culture methods and settlement for coral reef restoration

Files and links (1)

Metrics

Abstract

Details

Enhancing coral larvae culture methods and settlement for coral reef restoration

Files and links (1)

Metrics

Abstract

Details

Southern Cross University Social media