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Coral reef management techniques such as relocation and transplantation are increasingly implemented in the context of increasing coastal development and a global decline of coral reefs over the last 30 years. A 170 m submarine desalination pipeline was constructed in 2020 to discharge wastewater from the desalination plant for Hayman Island resort, Whitsundays, Queensland, Australia. Pre-construction site assessments were conducted indicating a healthy, diverse and recovering coral community between intertidal and 12 m depth in the proposed route of the pipeline. Mitigation options included the selection of a pipeline route that minimised impact on coral, and relocation and transplantation of hard corals. Two hundred and four corals comprising 35 species from 15 genera, with estimated sizes ranging from small (less than 2 kg) to extra large (over 50 kg), were relocated from the pipeline footprint to a similar nearby site. The estimated total weight of relocated corals was 873–2850 kg. The most common species transplanted were Hump Coral (Porites lutea) (27%), Lesser Star Coral (Goniastrea aspera) (8.3%) and Starflower Coral (Astreopora ocellata) (7.8%). Individual coral survivorship and growth was monitored at zero, one, six, 12 and 24 months. After 24 months total coral survival was 77.5%. The survivorship of relocated coral exceeded the mean for global coral restoration projects and was deemed successful by the regulator. To assist benchmarking of future coral relocation projects we propose a standard of below 50% as poor, 50–60% as below average, over 60% as acceptable and over 80% coral survival at two years as excellent. [ABSTRACT FROM AUTHOR]

Summary: The health and diversity of coral reefs are critically important to the stability and value of the marine tourism industry. Declines in coral reef health through climate change impacts and cyclones, and associated media coverage, have impacted tourism visitation. In January 2018, a major change in Australian Government policy included a Reef Restoration and Adaptation Program to investigate the best science and technology options for helping the Great Barrier Reef recover and adapt to the changing environment. We report on a trial of two intervention methods, mineral accretion and coral gardening, to improve hard coral recovery at a popular site on the Great Barrier Reef. We installed six artificial reef substrates onto which an equal number of coral fragments of seven species were transplanted over the course of two years. During this time, three of the six treatments were connected to a low‐voltage power source to encourage mineral accretion and enhance coral growth. Electrolysis resulted in substantial mineral accretion on the steel substrate, however, the technology had no positive effect on the survival or growth of transplanted coral colonies. After 13 months, a second round of transplanted coral fragments was undertaken, and the electrolysis was discontinued. Over a four‐year period, mean live coral cover increased significantly in both treatment locations, from 1.7% and 0% to 80.8% and 75.8%, respectively. Control locations increased insignificantly from a mean of 5% to 14.2%. The mineral accretion technology proved technically challenging and did not support the growth or health of transplanted corals, providing no evidence to support the use of mineral accretion technology for this purpose. The technology may, however, have applications in the creation of new, solid substrates and for initial rubble stabilisation efforts. These results demonstrate the effective use of artificial substrates in conjunction with coral gardening techniques for the recovery of hard coral at degraded tourism sites. [ABSTRACT FROM AUTHOR]

Coral reef ecosystems are under increasing pressure by multiple stressors that degrade reef condition and function. Although improved management systems have yielded benefits in many regions, broad‐scale declines continue and additional practical and effective solutions for reef conservation and management are urgently needed. Ecological interventions to assist or enhance ecosystem recovery are standard practice in many terrestrial management regimes, and they are now increasingly being implemented in the marine environment. Intervention activities in coral reef systems include the control of coral predators (e.g. crown‐of‐thorns starfish), substrate modification, the creation of artificial habitats and the cultivation, transplantation, and assisted recruitment of corals. On many coastal reefs, corals face competition and overgrowth by fleshy macroalgae whose abundance may be elevated due to acute disturbance events, chronic nutrient enrichment, and reduced herbivory. Active macroalgae removal has been proposed and trialed as a management tool to reduce competition between algae and corals and provide space for coral recruitment, in the hope of restoring the spatial dominance of habitat‐forming corals. However, macroalgae removal has received little formal attention as a method of reef restoration. This review synthesizes available knowledge of the ecological role of macroalgae on coral reefs and the potential benefits and risks associated with their active removal. [ABSTRACT FROM AUTHOR]