diver with device on coral reef

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 (as known as 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 2022, we are building on previous work by studying two additional species, and comparing newly settled corals with microfragments - small sections of adult colonies fragmented off the main colony. 

Corals will be collected at Davies Reef in the central region. The team will spawn, settle and rear coral recruits on devices in SeaSim. Early in the new year, coral recruits as well as microfragments will be placed back on Davies 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 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.