Over the course of 17 days Hannah and I have dismantled 16 reefs, scrubbed algae off of 480 cinderblocks, kayaked 40 miles with cinderblocks and equipment, and re-assembled 16 artificial reefs for my first project as a Ph. D. student.
This summer I am investigating how structure complexity and predator presence affects patch reef communities. A project that has stemmed from my curiosity in the separate and interactive effects of human impacts on bottom- up and top-down processes in coastal ecosystems. More on the project after the jump.
For my experimental design, I have made 8 artificial reefs that resemble structurally degraded reefs (third photo) and structurally complex reefs (second photo) that have a diversity of structure for marine life to hide in (i.e., small holes, tunnels, and branching structure).
For predator presence and absence, I am using Nassau grouper as my patch reef predator. This is the main reason, if you were wondering, why we couldn’t simply make new reefs with fresh clean cinderblocks. Nassau grouper settle onto patch reefs at a very young age and are known to have high site fidelity until they move out to large coral reefs as adults. Luckily for me, all of our artificial reefs were stock full of juvenile to sub-adult Nassau grouper and we have been extremely successful at safely removing Nassau grouper from half of the reefs (i.e., grouper were caught alive and re-located).
So far in our surveys, we have seen quite a diversity of fish colonize and recruit to our reefs (check out the trumpet fish on week one of our fish surveys) and I am very excited for our next steps which involve adding coral propagules to measure coral growth on each treatment, and surveying natural patch reefs for general patterns we may find on our artificial reefs.