Morphology, lipid composition, and reproduction in growth anomalies of the reef-building coral Porites evermanni and Porites lobata

Abstract

Growth anomalies (GAs) are protuberant masses found on many coral species; their presence may be linked to increased ocean temperatures and bleaching stress. In 2014 and 2015, Hawai‘i experienced back-to-back beaching events, after which an increased number of growth anomalies were noted on massive Porites colonies. GAs and normal tissues were sampled from 19 P. evermanni and P. lobata colonies in 2015 and from each of 15 separate P. evermanni colonies on six dates from June 2016 to August 2017, encompassing two annual reproductive cycles. Compared to normal tissue, GAs had significantly larger corallites in all dimensions in both P. evermanni and P. lobata. GAs of P. evermanni also had reduced amounts of lipid and lower functional lipid ratios across all time points. Across tissue types, lipid content was generally higher in winter (December) and spring (April) than in summer months (June/July), but was not correlated with reproductive condition. While GAs are generally non-reproductive in other corals, GA tissues in P. evermanni contained elevated numbers of oocytes in 2017. Compared to normal tissue, GAs in P. evermanni had aberrant corallite morphology and likely committed proportionally more energy to growth and less to energy storage.