Technology Solutions for Overcoming the Coral Recruitment Bottleneck.

Recruitment is a vital demographic process that replenishes populations and increases genetic variation, making it fundamental to ecological resilience. On coral reefs, rates of coral recruitment and post-recruitment survivorship are naturally low, resulting in a bottleneck to population growth and restoration efforts. Therefore, we investigated the potential that two technologies, specialized settlement modules and the Underwater Zooplankton Enhancement Light Array (UZELA), improve early life success. We hypothesized that greater complexity of specialized settlement modules increases larval settlement rates in tanks and the combination of settlement modules with UZELA increases subsequent recruit survivorship and growth on the reef. We found that complex settlement modules enhanced recruit settlement, survivorship, and growth relative to the lowest complexity module. The addition of UZELA to the settlement modules further doubled survivorship and quadrupled growth. Our experiment demonstrates a proof-of-concept that combining these novel technologies offers promise for reducing the time for corals to complete their most vulnerable phase of life, accelerating the timeline for establishing genetically diverse coral populations, and offering a possible step-function change in coral recruitment success that could help overcome the recruit survivorship bottleneck in coral restoration.