Standard Presentation (15 mins) Australian Marine Sciences Association 2022

Midday is better than all day: Optimising deployment strategies for rapid settlement of Acropora tenuis larvae for coral reef restoration   (#392)

Kerry A. Cameron 1 , Peter L. Harrison 2
  1. Southern Cross University, Coffs Harbour, NSW, Australia
  2. Southern Cross University, Lismore, NSW, Australia

Coral reef ecosystems are declining globally, accelerating development of coral reef restoration methodologies. Supplying coral larvae directly to natural substrata can restore corals to degraded coral reefs, and optimising deployment strategies to maximise settlement will improve cost-effectiveness. We investigated the effect of time of day and the length of time for larval containment on settlement rates at a degraded reef in the Philippines, using competent Acropora tenuis larvae settled under nets in five different time periods. Settlement was highest when larvae were deployed at midday, while the length of containment did not significantly influence settlement within the periods tested (3-9 hours). Settlement was also positively influenced by the seal of the containment nets against the irregular natural substratum. Our results show that larval restoration using competent A. tenuis larvae to restore targeted areas of degraded coral reefs could be optimised though strategic provision of the larvae during midday periods, under close-fitting containment nets with a good seal against the natural substratum. Importantly, midday release appears to enhance rapid settlement (< 3 h), therefore targeting release times for this period is more beneficial than extending larval containment for longer periods.