Assessing the coral reefs of Micronesia

The atolls of Micronesia provide excellent reefs to study because many are so far from large human populations. Our work here is to perform a baseline study of the abundance, diversity and health of the corals that inhabit these reefs and gather information on any diseases present. During these dives, we count hard and soft corals and categorize them by genera and size class. We are also gathering information on the type of cover, i.e., macroalgae, coral, sand, crustose coralline algae, etc., that dominates along our transects, and the numbers and genera of fish that are present.

Many of the reefs we are accustomed to seeing in Hawaii and the Caribbean show obvious signs of disease and degradation. Happily, the corals at the Micronesian atolls we have thus far visited appear healthy and largely devoid of disease. We have sampled the few coral colonies found exhibiting signs of disease and those will be brought back to the lab for histological analysis. Histology is the study of cells and tissues and this is done by using light microscopy. Preserving the coral tissues in fixative at the time of collection allows us to better understand the disease processes that are taking place and how (if) the coral is responding to the stress.

Interestingly, we found that the abundance of reef fish at the inhabited atoll (approximately 1000 people) was very low and no top predators were spotted while at the uninhabited atoll fish abundance was quite high and sharks and large pelagic fish species were seen. Food for thought...

Check out the reef slideshow on the left!