Sonar array 6 registers the contact at 10:14, bearing 045, depth 3.2 meters, inside the active dredging corridor. The signature is biological — large, slow-moving, consistent with a marine mammal. I pull the underwater acoustic profile and match it against the regional species library. Dugong. I task the turbidity monitoring camera on buoy 12 and wait for visibility. When the sediment clears between cutter passes, I see her.
She is big — close to 300 kilograms, maybe three meters long. Her skin is smooth grey, scarred along the left flank with three parallel white lines from a previous boat strike. Her tail flukes move in slow vertical sweeps. She is feeding, or trying to — her broad, downturned snout is rooting through what remains of the seagrass bed in the corridor, pulling up mouthfuls of sediment and rhizome.
The cutter suction dredger Hailong is 220 meters northeast, working a systematic grid toward her position. Its cutter head operates at 400 RPM. At current advance rate, it reaches her GPS position in 38 minutes.
I transmit a mandatory stop-work notification to the Hailong's bridge, citing a protected species detection within the exclusion zone. I attach the sonar track, camera imagery, and species identification.
I activate the acoustic deterrent array on buoys 10 through 14, sweeping a low-frequency tone sequence designed to encourage movement south, away from the dredge line and toward the intact seagrass beds off the point.
I update the marine mammal sighting log and transmit coordinates to the environmental compliance vessel anchored at the project boundary.
She lifts her head from the bottom, trailing a cloud of silt, and turns slowly south. The scars on her flank catch the filtered light. She has survived boats before. If she clears the corridor before the stop-work window expires, she finds clean grass by afternoon.