Coral Reef CSI at Olowalu?
Last weekend, Riley Coon, Trilogy’s Director of Operations and Kelly Montenero, Trilogy's Marine Conservation and Education Director, got to learn about how to conduct a coral reef forensics assessment- finding out the “whodunnit” amongst the various threats that corals here in Hawai’i face. Organized by the Maui Nui Marine Resource Council Coral Recovery Team and led by Dr. Bob Richmond, the training was a gathering of community members with a stake in reef health in Maui Nui- be it in fishing, kayak tours, research, traditional use or snorkel trips. The training was held at Olowalu, also known as the “mother reef” of Maui Nui because coral spawn from the centuries old coral colonies in the area go on to seed reefs throughout Maui Nui.
Participants learned how to recognize various indicators or “warning signs” of coral health from Dr. Bob, and then went out into the field, snorkeling as a team to monitor these indicators and take a "snapshot" of how the coral reef is faring at Olowalu. Then, everyone gathered together to share what they had observed and lessons learned.
Wondering how you yourself can start to recognize signs of declining coral health? Here’s some indicators of reef health to look for next time you’re snorkeling or diving.
Try to spot the guard crabs (Trapezia intermedia) that live within cauliflower coral (Pocillopra meandrina). These crabs protect the coral from coral- eating sea stars like Crown of Thorns by snipping at their bellies, and in exchange the coral animal produces a tasty lipid snack for the crabs, as well as providing shelter. However, this mutualistic relationship breaks down if the reef is under environmental stress. These indicator species will give us an idea of the complexity of the coral reef ecology and biodiversity in the area.
Are there keiki coral? Dr. Bob elucidated the point to us that even though a reef may have healthy 100-year-old colonies, if there are no 2 or 3 year colonies, that means that the reef is dead and just doesn’t know it yet. If there is no reproduction and no baby corals settling out and adding to the reef structure, then something is wrong in the area. It could be excess pesticides or chemicals in the water, changing when corals spawn, or a change in sediment, which determines where coral can start to establish themselves.
The sand can give us a clue to whether a reef is doing well or could use some help. Look closely at the grains to see whether they came from the sea (good) or from land (bad). Usually, sand grains from the sea, like tiny bits of urchin spines and other calcium carbonate based plants and animals are a lighter color and a good sign on the reef. If sediment looks like it was recently eroded into the ocean, it can be bad for the reef in that it could smother coral and even create anoxic conditions. A good sign to look for from a snorkeling distance are “white volcanoes”- cones of stirred up sediment from burrowing shrimp, signs of a healthy reef.
Can you see signs of animal activity, even if it’s not happening as you snorkel? Many snails and other invertebrates are active at night, so look for snail and crab tracks as an indicator of a healthy reef ecosystem.
Want to check out Olowalu for yourself? Come and join us on our Discover Olowalu snorkel sail!