What is Reef Resilience?

There are about 6000 described coral species worldwide that live in a range of environments. Some can survive along the equator in the warmest salt water on the planet while others thrive below 18°C in cooler temperate waters. As global sea temperatures rise the stress on coral species who prefer cold water increases. Stress increase in corals due to a rise in temperature can leads to coral bleaching, often resulting in coral morality. Corals have species specific environmental parameters that they require, some able to withstand warmer temperatures for longer and some cannot. Those that favour warmer water or can tolerate a large range in temperature variance are more resilient to the effects of warming waters. It is important to consider the use of these resilient corals when designing an experiment with the aim of longevity.

What is a coral fragment?

A coral fragment is the term used for a small piece of coral that has broken off the parent colony. This is one of the main ways corals can reproduce, by duplicating themselves through asexual reproduction. The fragmentation process naturally occurs due to wave action, storm damage and impact from other animals. The main concern during these events is that while there is potential for the broken coral fragment to continue its life, most of the time the environmental conditions are not in its favour, and the fragments dies.

Where and why?

The team has focused on Bundegi Reef in the World Heritage listed Nyinggulu (Ningaloo) Reef Marine Park, as a pilot study site to assess the effectiveness of this technique in WA. The once healthy and vibrant Bundegi Reef experienced devastating destruction during cyclone Vance in 1999 and then again during the marine heatwave event on 2010/2011. The reef has struggled to recover ever since which has had lasting negative impacts on the fish community that depends on it. With increasing pressures on coral reefs globally due to increasing water temperatures, early intervention could be the key to increasing biodiversity on Bundegi reef system.

What is the plan?

Scientists will attach fragments of specific heat resilient coral species to reef stars on the sea floor. This technique has been developed and successfully applied in other parts of the world through the Bees, Seas, and Trees program by Mars Incorporated, to see healthy reef restoration and development.

What is a reef star?

A reef star is a hexagonal steel structure, each 1m x 1m that sits above the sea floor. The plan is to lay multiple structures together in a matrix to create a web above the sea floor.

Why this design?

This design can cover a large area of the bottom substrate where juvenile coral fragments would normally struggle to survive e.g., on rubble or sediment, and is simple to install. The important feature of this structure is that the coral fragments will sit above the sea floor, so they do not get buried, yet the open frame allows space for multidirectional growth.