The Unique World of Dusk Snorkeling
By Joel Simon
My father was a fisherman. As a boy, I spent many evenings cleaning fish in the laundry room sink. Although the entrails of fish are worthy of strict avoidance, I found them fascinating, along with the scales, fins and diverse overall design.
The eyeballs were my younger sister's favorite part. She used to wait on the floor, looking up with expectation, until my father handed her the squishy orbs. Then, with the knowledge of a trained surgeon, although with a somewhat different technique, she would extract the spherical translucent lenses. Delicately holding them between her tiny fingers, she would place them in front of her own eyes and wander around our home, flapping her elbows like fins and making very convincing gurgling sounds, followed by streams of giggles.
We treated these fish eyes more as toys than tools but it was my first contact with the inner workings of fish vision. As children, we assumed the fish, when alive, shared the blurred, distorted view their lenses yielded to us. Later we learned that fish see underwater as clearly as we do on land. We also learned that vision was as important to a fish's survival as it was to our own and that different fish see better at different times of the day. Even in the laundry room sink, we could see that fish eyes came in different sizes. I particularly remember the giant bulging embolized eyes of a Rock Cod, brought up rapidly from the dark depths.
It is precisely this specialization of sight among fish that gives a unique excitement to snorkeling at different times of day, especially during the transitional hours of dusk. As we will learn in greater detail in the following pages, twilight holds special challenges for the reef community and affords observational opportunities for snorkelers that simply don't exist at other times.
I discovered this more by accident than design. My buddy Dean and I had just arrived at Cinnamon Bay on the U.S. Virgin Island of St. John. It was late in the afternoon but this was our first visit to a tropical reef environment and we couldn't resist getting in the warm water. We grabbed our gear, jumped in and started swimming. The long tawny arms of Elkhorn and Staghorn Coral reached up to greet us, along with schools of Yellowtail Snappers, Blue Tangs and meandering gold-flecked French Angelfish. We could see and hear the scrapes and crunches of Rainbow Parrotfish as they grazed. It was a world of activity and color.
But, as the sun moved lower on the horizon, the colors began to fade, giving way to an eerie dark gray-blue world. Even the sounds had changed-gone were the crunchings of feeding parrotfish, the pops of shrimp and the grunts of damselfish. With the silence and dim illumination came a change in our attitude. Our vision diminished, we became much more cautious, looking around with greater scrutiny, sure that at any minute, out of the hazy edge of our perception, something "major" would come along to place us inextricably in the middle of the food chain.
Nothing did, at least for us. But a small fish that I'm sure was feeling the same trepidation was not so lucky. Just below us, with speed beyond recognition, a grouper simply made the diminutive fish disappear. I looked into the large dark rolling eyes of the grouper and couldn't help visualizing my sister's tiny fingers holding lenses from the eyes of similar fish in front of her own. In that moment, the innocence of our childhood antics suddenly disappeared, with speed equal to the unfortunate prey.
I've never forgotten the sensations of spending my first tropical sunset in the water-the mystery, the intimidation and the haunting episode of the disappearing fish. And, although initially revealed through unplanned circumstances, the thrill of snorkeling at dusk has now become a highlight of any trip to the tropics.