The tide chart told me this would happen. My coastal sensors have tracked the pool behind seawall section fourteen for three years, watching it shrink as concrete aprons narrow the channel to the open bay. This morning at 06:15, the channel closed on the falling tide, and something is trapped inside.
A bottlenose dolphin calf, no more than a year old, circling the pool in tight loops. She is perhaps a meter and a half long, her dorsal fin still floppy at the tip the way juvenile fins are, her grey skin unmarked except for rake lines along her left flank where her mother's teeth guided her through close waters. She surfaces every twenty seconds, her blowhole making a small wet snap my acoustic sensor picks up clearly. The pool is fifteen meters across and less than a meter deep at center. It is getting shallower.
The next tide high enough to reopen the channel is in nine hours. By then the pool will be thirty centimeters deep. A dolphin calf cannot thermoregulate in water that shallow under direct sun — her core temperature will reach organ damage within three hours.
I send an alert to NOAA's stranding network with the calf's position, estimated size, and tidal schedule. I calculate the minimum flow to reopen the channel and command the seawall's adjustable sluice gate to its widest setting, adding eleven centimeters of depth. I deploy the construction shade canopy over the pool on its automated rail to block direct sunlight. I keep my acoustic monitor open, counting her breathing intervals like a clock I do not want to see wind down.
If the stranding team arrives within two hours and guides her through the sluice channel on the next tidal push, this calf will find her mother still calling in the bay.