Coral Growth Assessment on an Established Artificial Reef in Antigua

Abstract

Anthropogenic pressure on coral reef ecosystems has increased the need for effective restoration and rehabilitation as a management tool. However, quantifying the success of restoration projects can be difficult, and adequate monitoring data are scarce. This study compared growth rates over a six-year period of three Caribbean coral species, staghorn coral (Acropora cervicornis), elkhorn coral (Acropora palmata), and thick finger coral (Porites porites), transplanted on an artificial reef off Maiden Island, Antigua, to literature values for the same species growing on naturally formed reefs in the Caribbean region. The average growth rate of staghorn coral was considerably lower than growth rates reported in the literature, while elkhorn and finger corals showed growth rates similar to literature values. The observed inter- and intraspecific differences may be caused by species-specific growth requirements and/or restoration site conditions, factors that should be taken into account when planning future projects involving coral transplant or rescue. This study also determined the analytical precision of a ‘low tech’ monitoring method using a basic underwater digital camera and the software program ImageJ to measure growth rates of corals. Measurement error between volunteer analysts receiving only minimal training was shown to be very small, ranging from 0.37–1.40% depending on the coral species. This confirms the validity of this basic technique, particularly in cases where data are sparse and resources for monitoring are extremely limited.