The Sick Man of the Sea: Using eDNA to Investigate the Impacts of Human Activities on the Biodiversity and Genetics of Coral Reef Assemblages

Coral reefs are under enormous pressure globally and are declining at a worrying rate. Their demise can be attributed to two main pressures: thermal stress, and the direct impacts of human activities. Coral reefs support a huge diversity of tropical fishes that depend on live coral, and are facing extinction possibilities given the bleak projections for the future of coral reefs. A healthy coral reef supports huge levels of biodiversity in tropical fishes, but declines in diversity, abundance and biomass of these fishes are apparent all over the world and are an early indication of reef deterioration. By monitoring different metrics of tropical fish biodiversity on coral reefs, we can understand how coral reef ecosystems are affected by different stressors, and this can inform which reefs are most vulnerable to biodiversity loss and which reefs are most important for conservation action. This project will harness the power of environmental DNA (eDNA) to monitor the biodiversity of reef-associated tropical fishes on different coral reefs. Environmental DNA is the DNA shed by an organism's natural processes (e.g. dead skin), and can inform which species are present in a given locality. The proposed project will: 1.) establish a baseline of biotic diversity on 'pristine' coral reefs; 2.) investigate how different human activities affect reef fish biodiversity; and 3.) investigate the potential of other molecular biomonitoring methods to complement eDNA.