Project Reefresh: Bait Reef rehabilitation is an innovative, multi-stakeholder reef rehabilitation project trialling three tools — MARRS reef stars, Coralclips® and Reef Bags.
Bait Reef is a mid-shelf reef located 65 kilometres to the northeast of Airlie Beach and beyond the fringing reefs of the Whitsunday Islands.
Situated in a ‘no-take’ green zone within the Great Barrier Reef Marine Park, Bait Reef is a popular site for snorkelling and diving for tourism industry and private vessels.
There is a total of 12 public moorings available in the southwest quadrant of the reef where vessels can safely moor and view marine life such as manta rays, Māori Wrasse, reef sharks, turtles, and various fish.
Like many reefs, the once vibrant coral population is showing signs of impact from accumulating environmental stressors.
For Bait Reef, key stressors have included coral bleaching, crown-of-thorns starfish and most significantly the impacts from Tropical Cyclone Debbie in 2017.
Project overview
In October 2021, a multi-stakeholder team came together to deliver Project Reefresh, a reef rehabilitation project designed to improve coral cover and conduct further research in two small sections within Bait Reef.
The targeted sections are adjacent to a series of large bommies known as the ‘Steppingstones’ on the southwestern edge of Bait Reef, which was previously considered one of the best dive sites in the Whitsundays, and where past stressors have left large areas of coral rubble and coral rock devoid of live coral.
Around 4000 live coral fragments from a total of more than 30 different species were collected from other less impacted areas of the Bait Reef complex as ‘corals of opportunity’ — coral pieces and colonies that were lying loose on the seabed and unlikely to survive long-term.
- Project Reefresh used:
- 200 reef stars
- 1000 Coralclips
- 12 reef bags
- 4000 live coral fragments, which were found lying loose on the sea-bed likely broken off by rough weather, large fish or other physical impacts.
- The project site:
- covered an area of approximately 500 square metres at the two locations, providing an opportunity for project partners to learn more about the capacity of the different techniques
- will involve regular site management and detailed monitoring and will run over five years from 2021 to 2026
- is in five to nine metres of water and accessible for scuba divers and snorkellers to visit. Visitors can access the site by private vessel or local tourism operators using the nearby public moorings. The site is described in the latest publication of ‘100 Magic Miles of the Great Barrier Reef (the Whitsunday Islands)’.
Based on previous research and rehabilitation projects, we were confident that with normal conditions, most of the live coral fragments would ‘cement’ to their substrate with naturally produced calcium carbonate and continue to grow.
However, one of the risks that was considered in project development, thermal bleaching, significantly impacted the site in early 2022 (see progress updates below).
Management and monitoring will continue until 2026. This will ensure accurate reporting on the level of project success and help stakeholders managing the Reef to continue to learn more about the possibilities of small-scale reef rehabilitation tools.
- Project Reefresh: Bait Reef rehabilitation is a joint initiative between:
- Great Barrier Reef Marine Park Authority (the Reef Authority)
- Queensland Parks and Wildlife Service
- with key funding from the Queensland Government’s ‘Reef Trails’ program.
- The project was also supported by:
- Mars Sustainable Solutions
- Coral Nurture Program (including the University of Technology Sydney)
- BMT Consultants
- Kiana Sail and Dive Whitsundays
This project will run over five years, from 2021 to 2026, and involve regular site management and detailed monitoring.
Key project funding came through the Queensland Government’s ‘Reef Trails’ program. This sought to create ‘scenic drives by the sea’ through increased public moorings, reef protection markers and other improvements.
Marine Park management agencies are working together in a way that is encouraged through the Great Barrier Reef Blueprint for Climate Resilience and Adaptation (Blueprint 2030), which encourages new ideas and partnerships to improve reef health.
The site is in five to nine metres of water and accessible for scuba divers and snorkellers to visit. Visitors can access the site by private vessel or local tourism operators, using the nearby public moorings.
Like many reefs, Bait Reef is showing signs of impact from accumulating environmental stressors.
This site was selected after desktop and field surveys. This included bio-physical, socio-economic, and logistical factors.
The specific project area was chosen due to its poor condition (low coral cover and extensive loose rubble), suitability for rehabilitation, ease of access (multiple public moorings), and recognition as a once high-quality dive site.
At the time of the rehabilitation works (October 2021) site condition was poor and natural recovery proceeding slowly after accumulating stressors, including coral bleaching, crown-of-thorns starfish outbreaks and most significantly, the impacts of Tropical Cyclone Debbie in 2017. The iconic ‘Steppingstones’ site within Bait Reef had been stripped of most coral cover, and adjacent fields of loose coral rubble were inhibiting coral larval settlement and growth.
The project site at Bait Reef can be accessed by the public to see reef rehabilitation projects in action. The rehabilitation site is immediately southeast of Public Mooring #209, next to a large bommie. Access is by either a private vessel or one of the local Whitsunday tour operators. Multiple public moorings near the rehabilitation site make access safe and easy. The site is described in the publication ‘100 Magic Miles of the Great Barrier Reef (the Whitsunday Islands)’.
The Great Barrier Reef Marine Park Authority and Queensland Department of Environment and Science have developed new policy on Great Barrier Reef Interventions. We are delivering and assisting in reef and island intervention projects, as recommended by the Great Barrier Reef Blueprint for Resilience.
Three specific rehabilitation tools were used and trialled at the Bait Reef project site.
- Mars Assisted Reef Restoration System (MARRS) reef stars: Reef stars are hexagonal metal frames that can be placed on the seabed. In areas of loose coral rubble, they provide a stable platform that can be used to attach live coral fragments to. These coral fragments can then continue to grow and eventually completely cover the reef star structure. They were originally developed by Mars Sustainable Solutions for use in Indonesia to rehabilitate reefs impacted by blast-fishing.
- Coralclip®: A Coralclip® is a small spring-loaded clip made of stainless steel attached to hard coral rock via masonry nails. A suitable fragment of live coral can then be held in place under the clip where it continues to grow. The Coralclip® was developed by the Coral Nurture Program, a consortium of reef tourism operators and University of Technology Sydney researchers.
- Reef bags: These ‘bags’ are made of organic coir netting, used to enclose loose coral rubble. The bags stabilise the loose coral rubble allowing crustose coralline algae, sponges and eventually coral larvae to settle and grow. First used in the Great Barrier Reef Marine Park in 2019 by BMT consultants, this trial at Bait Reef is an extension of that earlier work.
October 2021
The installation phase of this project was completed in two parts:
The first part, completed in early October 2021, involved installing 200 MARRS reef stars, each with 15 loose coral fragments attached and 1000 loose coral fragments attached to coral rock using Coralclips.
Live coral fragments were sourced from other areas of the reef that had not been as heavily impacted by Tropical Cyclone Debbie and/or had recovered more quickly from past impacts.
Numerous Marine Park, private industry and tourism industry representatives were involved over the five days on-site.
The second part of the installation was completed in late October 2021.
This involved an experimental trial of Reef Bags where they were randomly installed in a grid pattern alongside similar-sized piles of rubble (with no netting used) and areas of loose rubble.
Differences between the reef bags and the other treatments will be monitored through time. Another two large ‘artificial bommies’ of approximately six cubic metres were created using reef bags and piles of rubble to further test the technique.
Bleaching: January-March 2022
In early 2022 large areas of the reef were impacted by thermal bleaching. Observations by project partners indicated significant stress at the site (bleaching/white coral).
Datalogger records from the time (Diagram One below) showed that the site had constantly experienced temperatures above 28ºC between January and March 2022.
In 2022 aerial surveys confirmed the fourth mass bleaching event to impact the Great Barrier Reef in seven years.
It was the first mass bleaching event caused by heat stress during La Niña conditions, which historically produce cooler summer conditions at the reef, with higher-than-average rainfall and high cloud cover.
Severe bleaching (more than 60 per centof community coral cover bleached) affected 43% of reefs surveyed. Worst affected was the central region of the reef, where the most heat stress occurred.
The majority of the reefs bleached were exposed to moderate levels of heat stress (NOAA Degree Heating Week 5-8°C-weeks), which causes bleaching but lower levels of mortality (AIMS Coral bleaching events).
Monitoring: 13-15 June 2022
Monitoring of the site in June 2022 clearly showed impacts from the thermal bleaching earlier in the year. An estimated 30 per cent of coral attached to the Reef Stars had died with more still showing signs of stress.
Observation of the dead coral fragments showed that they had cemented onto the Reef Stars indicating they had been healthy and growing well in the period prior to the high temperatures.
Temperature datalogger information downloaded from the site supported the project team’s view that the bleaching observed earlier in the year was the reason for the mortality.
Reef Bags Monitoring: 17-20 December 2022
The Reef Joint Field Management Program (RJFMP) partnered with BMT and University of Queensland scientists on experimental trials of ‘Reef Bags’ to stabilise coral rubble and create three dimensional ‘coral bommies’.
These were initially installed in October 2021.
The coconut fibre (coir) mesh netting (~1m³) ‘Reef Bags’ were filled with coral rubble to stabilise it and compared against two other treatments: similarly sized rubble mounds (no bag) and flat areas of disturbed ‘control’ rubble.
The project wants to determine whether bagging (‘Reef Bags’) or piling (mounds) rubble results in greater rubble stabilisation, binding, coral recruitment, and fish abundance compared to control rubble beds.
Late in December 2022 a small team went out onboard project partner vessel ‘Kiana’ to monitor the Reef Bags.
Initial observations are that the coir netting has completely degraded from the bag treatments. However, the rubble remains in place for both bag and mound treatments, with slight slumping.
Monitoring: February 2023
Reef Star and Coralclip® monitoring was undertaken in early February 2023 onboard Marine Parks vessel Tamoya II.
Results showed that coral mortality on the Reef Stars was now greater than 50 per cent and soft corals had started to dominate the area around and below the Reef Stars.
Soft corals had even started recruiting to the Reef Stars structures and were possibly impacting hard coral survivorship.
Monitoring of the corals attached to the reef with Coralclips showed average survivorship (across the timed swim surveys conducted) of 42 per cent.
Images (below) show the same corals (attached with Coralclips) in October 2021 (installation) and 15 months later (February 2023).
An increase in soft coral growth can be observed along with growth of the attached Acropora corals.
Addition of Coral: August/September 2023
Following the monitoring surveys in February 2023 a decision was made to replace some of the coral that had died because of the bleaching in early 2022.
While the risks from further bleaching and the expanding soft coral populations remain, there is opportunity to learn more about reef rehabilitation and its opportunities and limitations.
From the afternoon of 30 August to 2 September a team of five divers supported by Marine Parks vessel ‘Reef Resilience’ and its crew undertook a total of nine dives at the site.
Healthy coral fragments were collected from another area of Bait Reef, transferred by vessel across to the rehabilitation site, fragmented and then attached to the Reef Stars.
Before they were attached the Reef Stars were cleared of any remaining dead coral fragments across the top six bars and any algal growth scrubbed off.
The coral species collected and used on the Reef Stars can be considered to have withstood higher temperatures in early 2022 and may therefore have some extra thermal tolerance.
In total approximately 800-850 fragments of this coral were attached to 150 of the Reef Stars.
A total of 20 of the Reef Stars were individually tagged and photographed.
These will be carefully monitored over the next several years to see how well the coral grows and survives any impact such as high-water temperatures or expanding soft coral populations.
- Reef intervention trial projects like this one are:
- Not a replacement for major global action to address greenhouse gas emissions and the impacts of climate change on coral reefs globally.
- Not a replacement for continued efforts to address other impacts on the Great Barrier Reef.
- Designed to assist natural recovery processes in small areas of reef that have been impacted by environmental stressors.
- Potentially very useful to improve the condition of ‘high-value’ areas of reef (e.g. popular tourist sites or an area with identified specific high ecological value,) or repair areas of reef damaged by vessel collisions.
- Examples of partnership actions that may become more broadly used across the Great Barrier Reef.
- Designed to include technical and field-based training for stakeholders and ongoing monitoring and reporting to help improve scientific understanding and measure levels of success.
Bait Reef has become popular as a sailing and diving destination in recent decades.
This reef rehabilitation project is jointly funded by Great Barrier Reef Marine Park Authority and Queensland Parks and Wildlife Service, with contributions from other partners/sources, including volunteering some of their time, staff and equipment.
Additional funding came from Queensland Government’s Reef Trails program, which was designed to improve access to small vessel moorings at specific locations on the Reef and create a ‘reef trail’ for visitors to follow.
A portion of the funding was allocated to improve the quality of reefs at popular dive and snorkelling sites near existing moorings. Bait Reef is one such site.
Bait Reef is situated 65km to the north-east of Airlie Beach and beyond the spectacular Whitsunday Islands. It lies within the Sea Country of the Ngaro Traditional Owners, who have lived on these islands and waters for around 9000 years.
Bait Reef has become popular as a sailing and diving destination in recent decades.
