Development of a coral nursery as a sustainable resource for reef restoration in Abu Al Abyad Island, Abu Dhabi, United Arab Emirates, Arabian Gulf

Abstract

Populations of once dominant reef building coral Acropora clathrata in Arabian Gulf is declining, mainly due to thermal bleaching and anthropogenic factors such as rapid urbanization, toxic wastes, destructive fishing practices, land reclamation and sedimentation. To actively restore coral populations, continuous supply of corals is required without causing damage to the existing reefs. In this study, as part of the coral gardening approach, mid water coral nurseries were constructed in Abu Al Abyad Island, United Arab Emirates following the coral tree nursery model. Six hundred fragments, with an average length of 6.32cm (SD ±1.23cm) of Acropora clathrata were mounted in the nursery and reared for 21 months while monitoring the health of the fragments continuously and estimating the growth rate and survivorship of the corals every three months. Only 9.8% of mortality was recorded in the entire study period, while a linear growth rate of 6.44cm･year^－1 (SD ±0.72) was achieved in the first 12 months and 9.25cm･year^－1 (SD ±0.63) in the remaining 9 months. Almost negligible mortality and satisfactory growth of corals during the entire nursery period suggest that the coral tree nursery model is suitable for propagating A. clathrata in Arabian Gulf.