Thursday, October 19, 2017

Into that good night

"Do not go gentle into that good night
Old age should burn and rave at close of day;
Rage, rage against the dying of the light."
- "Do not go gentle into that good night" by Dylan Thomas

I hung suspended above the reef, neutrally buoyant, perfectly poised. In front of me, a huge silver tarpon slithered past, oblivious to my presence. My dive light scanned the ground in front of me, and a small crab caught my eye. I hadn't seen it before - well, I remembered it was in my ID book, but I couldn't remember its name. It had a thin, teardrop-shaped body and unbelievably long, skinny legs. Stenorhynchus seticornis, the yellowline arrow crab.

The reef does not go gently into the night. At dusk, little fish hide away, but the ecosystem is no less alive. Nocturnal invertebrates come out to feed. Coral polyps emerge, so the reef looks like it's covered in fuzz. There are giant, predatorial fish lurking. It is fascinating.

Swimming further down the reef, I noticed long black spikes peeking out from behind a coral. I tilted my feet and glided around the living rock to see what it was. The long, needle-like spines made the creature look like a predator's worst nightmare - there was no biting this guy and surviving. Some of the black needles swept slowly back and forth or in circles. They all traced back to a dark purple clump nestled in a crevice between corals. The long-spined urchin, Diadema antillarum.

A few minutes later, I noticed a long, sinewy, bristle-covered leg laying across a sponge. Following its curves, I found the disc-shaped center of the animal, then four more attached, equally-bristled legs. The angular brittle star, Ophiothrix angulata.

My boyfriend trained his light on a cavern underneath a coral head. He stayed there, suspended in the dark water, pointing out a creature to me. As I made my slow approach, I saw a flat, oblong crustacean. Like a lobster that had been squashed under a pile of books. He was larger than I expected and clawed at the rocky overhang above him. Scyllarides aequinoctialis, the Spanish slipper lobster. 

Fleshy green tentacles emerged from a coral head. I recognized them immediately as belonging to an anemone. The animal was hidden in a crevice, but by the diameter of the tentacle ring, it could only be one species: Condylactis gigantea, the giant anemone.

Gradually, we reached our turn-around point and proceeded up the reef to swim back at a shallower depth. As we climbed, I heard a strange sound. It reminded me of crackling cereal or frying bacon. Sound travels quickly underwater, so I dismissed it at first. Then it hit me: I had heard this sound before, in a seminar about snapping shrimp. The shallower I got, the louder the sound became. I never got to see them, but it had to be Alpheus armatus, the red snapping shrimp.

The rocks and corals became more sparse the higher we climbed. At the edge of the reef, nestled between two large rocks, I saw a long, soft tube. It was mottled brown and white, with a smooth surface spotted with triangular bumps. The tiger tail sea cucumber, Holothuria thomasi.

We swam back to the dock over the sloping sand plain, and even here were there animals raving at the close of day. Every few feet, I passed over a small round hole in the sand with two tentacles emerging. The tube worms were feeding in the darkness, Mesochaetopterus sp.

Arriving back at the dock, I marveled to myself how active the reef is at night. Rage, rage against the dying of the light.

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