Production of multi-generation of stress-tolerant corals for reef restoration in Pangasinan, northwestern Philippines

Maria Vanessa Baria-Rodriguez, Ph.D.

Sexual propagation of corals for reef restoration is more advantageous than asexual propagation as it leads to high genetic diversity and provides access to millions of propagules. Most of the studies on the sexual mode of propagation focus on fast-growing, less stress tolerant Acropora species. Long-term studies on massive corals as material for reef restoration using the sexual mode of propagation is still lacking despite the fact that massive corals are generally more stress tolerant and slow to recruit naturally to degraded reefs. Here, we report on the survivorship, growth, and reproduction of two sexually propagated, massive coral species (Favites abdita and F. colemani; F1 generation), outplanted to the reef and monitored until 12 years post-fertilization (2009 - 2021) and its production of F2 generation of propagules. In 2009, gravid parent colonies were collected generating F1 parents which were outplanted in 2011. After 6 years, almost 90% of outplanted colonies were sexually mature and after 12 years, colony diameter ranged between 3.0 - 31.6 cm and 3.5 - 21.0 cm for F. abdita and F. colemani, respectively. In 2021, gravid F1 colonies were spawned generating F2 gametes. F2 generation larvae were successfully collected and successfully settled on artificial substrates for both species prior to outplanting on the reef. By far, this is the first study to demonstrate long-term sexual propagation of massive corals. It is highly recommended to use multiple species, with various life history strategies, via sexual propagation to restore and sustain coral population in degraded reef areas.