Erosion vs. accretion of sandy beaches: their impacts on nursery areas of coral reef fish

Sandy beaches have experienced substantial human modifications worldwide for centuries. Yet, sandy beaches are known as nursery areas for coral reef fishes. Due to global and local stressors, the degradation of nurseries such as the sandy beaches may have wide reaching consequences for the resilience of reef fishes. In our study, the impact of erosion vs. accretion phenomena was highlighted on coral reef fish community in Guadeloupe in comparing the abundance and diversity of juvenile fish between two nearby beach sites (one that undergoes accretion and the other one that undergoes erosion since the 1950s). The main result showed that a significant retreat of sandy beach along the entire coastline, by bringing out an old reef, could create new habitats, favorable to the settlement of fish juveniles. This result is surprising when considering that erosion negatively affects coral reefs through the sedimentation, deterioration of water quality, and loss of habitat.