Coral reef ecosystems are declining globally, accelerating development and uptake of coral reef restoration methodologies. Supplying coral larvae directly to natural substrata can re-establish corals on degraded coral reefs and is one of the reef restoration methods being applied through the Reef Co-operative, a new collaboration between Traditional Owners, scientists, tourism operators and a conservation group. Working together, we captured coral spawn at Moore Reef on Gunggandji Sea Country, raised the larvae until competent, then transferred 6 million to recruitment-limited Hastings Reef on Yirrganydji Sea Country for settlement. We investigated the effect of different larval delivery methods on settlement, including under two sizes of larval containment net and spraying larvae directly onto the reef with no containment. Settlement was highest when larvae were delivered under the smallest nets placed over the least irregular natural substratum. The manageable size of these nets was a positive attribute for our diverse team with varying prior experience in field work like this, but they were also the most resource intensive to produce and deploy. Our results illustrate the trade-offs between high larval settlement rates, cost-effectiveness and manageability of larval delivery methods, particularly for multi-partner projects with social as well as environmental objectives
