Empirical Analysis of Coral Reef Degradation and Recovery Potential in Nigerian Offshore Reefs

Nigerian offshore reef structures in the Gulf of Guinea support fish assemblages of commercial and ecological significance, yet their degradation status and capacity for recovery under reduced stressor conditions remain poorly documented relative to better-studied reef systems in the Caribbean and Indo-Pacific. This study provides an empirical analysis of coral reef degradation status and recovery potential at four offshore reef systems in Nigerian waters: Tarkwa Bank reef near Lagos, Sao Tome Bank, Ramos reef off Delta State, and Dodo reef off Rivers State. Structured belt transect surveys by SCUBA divers document coral cover, coral species richness, bleaching prevalence, macroalgae cover, and fish assemblage metrics (species richness, biomass density) at each reef during two survey periods (January and July 2024) representing thermal stress minimum and maximum conditions. Coral skeletal growth extension rates are estimated from x-radiographed cores of three Diploria labyrinthiformis colonies per reef as indicators of historical growth performance. Coral heat stress exposure is assessed using cumulative bleaching degree heating weeks from NOAA Coral Reef Watch satellite products for the preceding five years. Recovery potential indices are computed using a multi-metric framework incorporating coral larval connectivity estimates derived from Lagrangian particle tracking and local stressor intensity scores. Regression analysis tests the hypothesis that degree heating week exposure is the primary predictor of current coral cover. Recommendations propose national reef monitoring standards and temperature stress early warning systems for offshore reef management. Keywords: coral reef degradation, offshore reefs, Nigeria, bleaching, reef recovery potential