Evaluation of staghorn coral (Acropora cervicornis, Lamarck 1816) production techniques in an ocean-based nursery with consideration of coral genotype

- Two common nursery grow-out methods for A. cervicornis are compared.
- Colonies cultured on trees grew two-fold faster than those grown on blocks.
- Post hoc rankings of genotype growth were identical between culture methods.
- Location (depth and position) of colonies on trees did not affect growth.
- Block cultured colonies bleached sooner but survived longer than those on trees.

Staghorn coral Acropora cervicornis is an important framework-building species that has declined severely throughout the Caribbean since the early 1980s. This species is now widely cultured in ocean-based nurseries to restore degraded populations. A variety of techniques have been adopted to grow A. cervicornis for restoration purposes, however the effect of each of these methods on nursery-reared corals is not well-understood. In particular, systematic evaluation of nursery-reared A. cervicornis between water column-suspended and benthic-attached culture methods is lacking. To better understand the effect of these techniques, a one-year A. cervicornis propagation experiment in the Florida Keys was conducted to compare growth, condition, and survivorship between common suspended (i.e. tree) and benthic-attached (i.e. block) grow-out methods. The effect of coral genotype on growth was also considered. Colonies were measured and monitored monthly from December 2014 until November 2015, when only three colonies had survived an extreme bleaching event. Colonies on trees grew up to three times faster than those on blocks and the location of colonies on trees did not affect growth. Genotype had a significant effect on colony growth, which was consistent across grow-out methods. Interestingly, colonies grown on blocks bleached sooner but survived longer than those on trees. These findings contribute to a growing understanding of A. cervicornis nursery culture, and could aid in the selection of culture methods and genotypes for coral nurseries throughout the wider Caribbean.