First insights into coral recruit and juvenile abundances at remote Aldabra Atoll, Seychelles

• DOI: 10.1371/journal.pone.0260516
• Publication Date: 2021-12-07T13:34:38Z
• Authors: Anna Koester; Amanda K. Ford; Sebastian C. A. F...; Valentina Migani; Nancy Bunbury; Cheryl Sanchez; Christian Wild
• Keywords: Atoll; Stylophora pistillata

Coral recruitment and successive growth are essential for post-disturbance reef recovery. As coral recruit juvenile abundances vary across locations under different environmental regimes, their assessment at remote, undisturbed reefs improves our understanding of early life stage dynamics corals. Here, we first explored changes in abundance three (lagoon, seaward west east) remote Aldabra Atoll (Seychelles) between 2015 2019, which spanned the 2015/16 global bleaching event. Secondly, measured variation on settlement tiles from two sites reef) during August 2018-August 2019. Juvenile decreased 14.1 ± 1.2 to 7.4 0.5 colonies m-2 (mean SE) 2015-2016 increased 22.4 2016-2019. Whilst two- three-fold lagoonal western 2016-2018 (from 7.7-8.3 17.3-24.7 m-2), increases eastern occurred later (2018-2019; 5.8-6.9 16.6-24.1 m-2). The composition recruits was dominated by Pocilloporidae (64-92% all recruits), 7- 47-fold higher inside than outside lagoon. Recruit highest October-December 2018 (2164 453 m-2) lowest June-August 2019 (240 98 Acroporid corresponded this trend, results suggest that broadcast spawning October-December, when water temperature 26 29°C. This study provides published record Seychelles Outer Islands, indicates a rapid (2-3 years) increase corals following event, crucial baseline data future research resilience connectivity within region.