Our Flat Friends!
By: Ethan Dewald
Southern Stingray (Hypanus americanus)
A stingray at Dry Rocks, Key Largo coming to say hi to me!
The dust cloud approaches as I lay as still as possible on the ocean floor. The rippling outer edges appear out of the murk first, as the rest of the flattened body emerges into view. My subconscious hints that I should be wary, since the stingray is still a wild animal, but my rational brain reminds me that I am more of a threat to this creature than it is to me. I remain in place as the Southern stingray approaches me on the sandflat.
Stingrays, like sharks, are elasmobranchs and are comprised of a flexible cartilaginous skeleton and ultra-sensitive electroreceptive organs called the Ampullae of Lorenzini, which allow them to detect minute electrical fields caused by a prey’s heartbeats and nerve impulses. A ray’s mouth is located on the ventral side (bottom of the ray) closest to the seafloor, with a large flattened body structure that allows their electroreceptor organs to be spread over a larger surface area to detect buried invertebrates and small fish in the substrate. Southern stingrays can be differentiated from other benthic rays by the irregular row of short spines along the center of their back, and the disc of the Southern stingray is more diamond-shaped and angular than those of other benthic rays.
Stingrays have their mouths on the bottom of their body and use electroreceptive organs to search for prey hidden in the sand
Southern stingrays can be seen on almost all trips that students can participate in here at MarineLab. From seagrass beds and mangrove root systems of Largo Sound and Florida Bay, to the coral reefs we visit in the Florida Keys National Marine Sanctuary, and even on one of our more specialized field trips, such as Rodriguez Key and hardbottom sites. Southern stingrays are benthic rays, which means they reside mainly on the ocean floor (compared to oceanic/pelagic rays like eagle rays and manta rays that free swim in the water column). They can grow over six feet in diameter and can weigh more than two hundred pounds and can range in color from gray to olive green to brown.
Southerns are masters of disguise when they bury themselves in sand!
Many students are frightened and uneasy about getting in the water with stingrays. But, getting hurt by a stingray is incredibly unlikely; they’d much rather run away from humans! I was just as guilty of this fear when I started diving with sharks and rays; honestly, the rays scared me more than the sharks did. But going on two years now since I started diving with sharks and rays, I have come to love my flat friends and the close encounters I’ve been lucky enough to have with them. I hope to share these experiences with students if and when they come to MarineLab!
