This rare kind of splashing is made by a barely submerged bottlenose dolphin chasing fish at great speeds in shallow water.
Everyone has heard the saying, "They only come out at night." No one is surprised to see birds fly south rather than north for the winter.
In our local waters, there are twice as many dolphins in the summer as in the winter. All these facts lead to a question: Why is winter the time for teens?
Lately Capt. John Heideman and I have been seeing a couple more dolphins than is average for this time of the year, widely scattered and apparently operating independently from one another. There is often more cooperation between scattered dolphins than meets the eye.
A gray dorsal fin flickered in the alcove of the local bay and then remained submerged so long we thought we had glimpsed a shark rather than a dolphin. It wasn't hard to wait. The gentle morning was beautiful. There weren't any clouds. With barely a breeze, the sea surface was like glass marred only by armies of small ripples that look like pockets of baby blue texture against ice–blue surroundings.
Eventually the gray dorsal fin resurfaced and revealed itself as Oyster, a teen bottlenose dolphin we've known since 2004.
Like teens in all walks of life, Oyster was focused on feeding. His technique was to swim in a fast small circle and then pump the muddy seafloor a couple of times to create mudplumes. I don't know if this action corrals the Piscean object of his desire like a fence around the dog or serves to funnel the fish’s course of escape. Perhaps it was the latter.
Each of Oyster’s small fast underwater circles left trails of footprints on the still sea surface but the dolphin himself with surfaced several feet away. Sometimes he embellished his normal breathing position by spyhopping in a head-first vertical posture like a person popping his head out of the water, sinking backwards into it like a person sinking back against the pillow, and snapping his jaws around the fish to secure it for swallowing.
He repeated this technique over and over, his glassy trails hypnotizing more than just the fish, until it was time for us to continue on our way.
We passed by Oyster’s alcove some time later that morning but didn't see him and kept going. Soon another large gray body lunged at the surface. As we did with Oyster, we had to wait awhile to see the large gray body again. It was a dolphin, all right, but it was as hard to track as Oyster’s glassy circles had been easy to track.
By now the winds had awoken. The currents, always brisk near John's Pass, were downright pushy. They required constant adjustments against the tiny whitecaps that jostled and slapped our boat.
This dolphin was also a teenager; we call him PC, not for the computer but as the acronym P’s Calf. He's bulking up beautifully, a testimonial to his success as a wild dolphin.
In striking contrast to Oyster’s placid glassy trails for catching fish, PC used the rare, rocketing and splashy foraging strategy called powersharking.
"Sharking" is when a dolphin swims under the water surface but keeps the dorsal fin exposed to the air. Dolphins usually use the sharking–swim style in very shallow water where they can't help but expose the fin, but they'll shark in deeper water as well.
Powersharking is when a dolphin sharks at great speed to catch fish, usually in water 1-2 feet deep. It takes all the great dolphin musculature to unzip the shallows by swimming a dozen miles per hour, water rooster tails rising like walls to left and right, or tail whipping – punching the water left, right, left with the powerful tailstock in wild pursuit of food. All this creates conspicuous splashes.
PC’s power sharking took place at the gently sloping beach leading to a verdant seagrass meadow. These are the perfect conditions for powersharking, and to our knowledge, the only kind of shoreline our local dolphins use for this dramatic display of foraging flexibility.
It wasn't surprising on the next encounter to find more teenage dolphins, known as sub-adults or adolescents in the technical literature, rather than members of other age groups because this is winter. Whether encouraged to capitalize on the aquatic vacancies left by the adults drawn to riches in other maritime regions or not drawn to those same riches to avoid being socially outclassed by those same dolphins is unknown. But here, winter is the time for teens.
Dr. Weaver studies wild dolphins under federal permit 16299, National Oceanic and Atmospheric Administration. Send her an email at dazzled@tampabay.rr.com or visit her website www.dolphinsuperstore.com. NOAA advises anyone who sees a stranded dolphin in the Gulf of Mexico to call 877-942-5343 or 877-433-8299.
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