Manta rays favor shallow water with strong currents
With Florida’s coast so highly developed, it is a surprising location for a nursery area. What’s more, these particular “urban manta rays” are also singling out some particularly hazardous locations.
“There’s this man-made inlet [Boynton Beach Inlet] that’s known for being one of the most dangerous inlets because it’s very skinny with seawalls, and boats come flying through. I try to avoid it at all costs,” Pate says.
Despite the risks, and the shallow water (Pate estimates Boynton Beach Inlet’s maximum depth to be around 10 m), the inlet seems to be a popular location for the manta rays. “They will come around and face into the current, which is really strong, and just sit,” says Pate, who sees groups of up to six manta rays sitting in the inlet for hours at a time.
“You just watch boat, after boat, after boat go right over them,” says Pate, noting that the manta rays can be in just a few meters of water when the boats are above them. “It seems like a really horrible place to be, so I’m really curious as to why they’re choosing that inlet.”
Exchanging floating oranges for slightly more accurate technology
Pate knew that currents in the inlet are fast, but to properly characterize the flow she needed to be able to measure them. However, the costs of purchasing an ADCP quickly became a major roadblock. In search of alternatives, Pate started to consider other, much less accurate, options.
“I did an experiment with the drone, where I tossed oranges into the water with the hope of measuring the surface current,” Pate says. Fortunately, when the Eco came along, Pate did not have to resort to oranges any more.