Data from: Continuity of seascape plays an important role in determining patterns of spatial genetic structure in a coral reef fish

Detecting the patterns of spatial genetic structure (SGS) can help identify intrinsic and extrinsic barriers to gene flow within metapopulations. For organisms such as coral reef fishes that are faced with major environmental stressors, identifying these barriers is critical to predicting evolutionary dynamics and demarcating evolutionarily significant units for conservation. In this study, we adopted an alternative hypothesis-testing framework to identify the patterns and predictors of SGS in the Caribbean fish Elacatinus lori. First, genetic structure was estimated using nuclear microsatellite genotypes and mitochondrial cytochrome b sequences. Next, clustering and network analyses were applied to visualize patterns of SGS. Finally, logistic regressions and linear mixed models were used to identify the predictors of SGS. Both sets of markers revealed low global structure: mitochondrial ΦST = 0.12, microsatellite FST = 0.0056. However, there was high variability among pairwise differentiation estimates, ranging from panmixia between sites on contiguous reef (ΦST = 0) to strong structure between sites separated by ocean expanses ≥ 20 km (maximum ΦST = 0.65). Genetic clustering and statistical analyses provided additional support to the hypothesis that seascape discontinuity, represented by oceanic breaks between patches of reef habitat, is an important predictor of SGS in E. lori. Importantly, the estimated patterns and predictors of SGS were consistent between both sets of markers. Combined with previous studies of E. lori, these results suggest that the interaction between seascape continuity and the dispersal kernel may play an important role in determining genetic connectivity within this marine metapopulation.