Testing retention and coral survival on seeded devices in a degraded environment

Coral seeding aims to accelerate the recovery of coral cover on degraded or damaged reefs by increasing the number of young coral settlers, particularly where the reef has a low larval supply (e.g., following a large-scale bleaching event). The aim is to increase the number of corals that ultimately recruit into the local coral population and contribute to coral growth and coral cover in the future. 

Dispersing small devices seeded with coral larvae or fragments allows corals to be placed on degraded reefs with minimal handling. To scale-up this method, these devices will need to be freely deployed in a fashion similar to sowing seeds. 

In November 2021, we will undertake a field experiment to test how well freely deployed devices are retained where they are placed, and how any potential movement of the device might impact the survival and growth of the seeded coral fragments. 

Seeded devices secured to healthy or mildly degraded reefs have resulted in high survival. Future work will be undertaken on degraded reefs and macro-algal dominated rubble reefs, to mimic the conditions where restoration would likely be required.  

In November 2021 we will also collect corals from Woppaburra sea county and bring these corals to the SeaSim. We plan to capture the spawn from these corals and settle these onto our devices.   

In early January 2022 we will deploy devices settled with coral recruits to degraded sites in the Keppel Islands. We will monitor their survivorship until the end of 2022 to identify whether corals survive and grow best on secured or freely deployed devices. This work will also allow us to identify the environmental conditions in which corals survive and grow best, and will enable us to compare the results from fragments and recruits. This information can help inform potential management practices to deliver and enhance the survival of young corals on degraded reefs.

Feature image credit: Dr Carly Randall

Researchers 

Dr Cathie Page 

Christine Giuliano 

Dr Line Bay 

Dr Carly Randall 

This research is supported by: 

BHP and AIMS, through the Australian Coral Reef Resilience Initiative (ACRRI)