How do waves and currents impact survival of young corals?

Coral seeding is a promising restoration method, but a major hurdle is the naturally high mortality rate of baby corals (coral recruits). Often, less than 10% of settled coral recruits survive their first year on the reef. 

To optimise reef restoration efforts, we need to better understand the environmental factors that influence these high rates of mortality, so we can strategically place young corals to reach restoration targets. For example, if mortality is typically higher in a particular environment, more coral may be deployed. 

In this research project, we will collect corals across a broad latitudinal gradient (Moore Reef in the northern region, Davies Reef in the central region, and Heron Reef in the southern region) and spawn, settle and rear coral recruits on devices in SeaSim. 

In January and February 2022, these coral recruits will be placed on mid-shelf reefs, in their natal habitats across the Great Barrier Reef, in environments with low to high wave energy. We will assess if survival is higher at sheltered sites with little water movement, or at sites with strong currents and high water movement.  

We will visit these sites throughout the year to monitor the growth and survival of the deployed coral recruits to get a better understanding of the reef environments in which coral recruits perform best.  

This work will be complimented with laboratory experiments in specialised flume-systems at SeaSim, to evaluate the effects of water flow dynamics on survival, growth and uptake of the symbiotic algae necessary for corals to survive and flourish.