Poster Australian Marine Sciences Association 2022

Bleaching severity and coral fecundity: implications for reef recovery potential (#506)

Nico Briggs 1 2 , Christine Giuliano 3 , Cathie Page 3 , Cinzia alessi 1 2 , Mia Hoogenboom 1 2 , Line Bay 2 3 , Carly Randall 2 3
  1. James Cook University, Douglas, QUEENSLAND, Australia
  2. AIMS@JCU, Townsville, QLD, Australia
  3. Australian Institute of Marine Science, Townsville, QLD, Australia

Future reef recovery relies on reproduction by coral survivors of major disturbances, but increasingly frequent and severe bleaching events are impacting recovery by decreasing larval inputs to reef systems. Furthermore, sublethal effects on corals that do survive bleaching may be further suppressing recovery, although these effects often go undetected. We investigated sub-lethal effects of the 2020 mass-bleaching event on inshore, turbid corals in Woppaburra sea country (Keppel Islands). Acropora millepora experienced high bleaching incidence but low mortality across the island group. We decalcified and dissected samples from fate and phenotype-known A. millepora colonies collected prior to spawning and 6 months after bleaching. We found a 9.4% decrease in average egg size in severely bleached colonies (0.55mm ± 0.01 SE) compared with the least bleached colonies (0.61mm ± 0.04 SE). We also present results on the impacts of bleaching on egg number. Results will be presented against the backdrop of a literature review on current knowledge of coral bleaching’s effects on coral fecundity. Identifying sub-lethal impacts of coral bleaching on survivors provides valuable insights into their capacity to contribute to recovery of coral populations.