Hi everyone! I saw so many urchins today!! Before I get into those, I’ll give a quick rundown of the day’s activities. Today consisted mainly of two projects: determining the percent coverage of live coral on the reef and collecting sea urchins. This morning we took a boat out to a patch reef in the lagoon and used transects and quadrats to count the number of live coral, recently dead coral, and macroalgae among other things to determine the health of the coral reef. Since sea urchins both help the coral by consuming the algae that live on them and harm the coral by boring into them, we also did a timed sea urchin collection to see how many urchins we could all catch and returned to the island to identify and measure them. In the afternoon, we repeated the morning’s activities outside of the lagoon.
Now on to the sea urchins!! In the lagoon alone, we collected over a hundred Echinometra viridis (a small brown/red urchin with spines that have a pale ring close to the body). We also found quite a few Eucidaris tribuloides (commonly known as slate pencil urchins, reddish brown body with blunt spines) and some Tripneustes ventricosus (an urchin with a black/dark purple body and short white spines) hiding in the coral crevices in the lagoon.
In the afternnon, we also collected some Diadema antillarum (a long-spined sea urchin whose spines easily penetrate skin) among the coral and a few Meoma ventricosa, both the live and dead versions (a flattened globe urchin with a reddish body and a five petal design on its back) buried in the sand along with the other species. It was interesting to me that we found the long-spined urchins and red heart urchins mainly outside of the lagoon, while inside we mainly were able to find the viridis species.
In other words, it was a very exciting day for me! I absolutely loved getting to find, hold, and work with the urchins more today. 🙂 I can’t wait to see what tomorrow brings and what echinoderms I’ll spot tomorrow. Thanks for reading everybody!