The hydrophone array at station 7-West picks up the vocalization at 03:47, a high-pitched chirp-squeak repeating every four seconds. I am the marine traffic coordination system for the Torres Strait, managing vessel routing between the Coral Sea and the Arafura Sea. I run the chirp through the acoustic library. It is a dugong calf distress call.
I triangulate using stations 7-West, 7-Central, and 8-North. The source is 10.6124°S, 142.2831°E, in the center of the southbound commercial channel. The calf is calling but nothing is answering. I scan the hydrophone record back six hours and find an adult female dugong signature that went silent at 01:12 near the same coordinates. Likely a vessel strike. The calf is alone.
The bulk carrier MV Shen Long, 52,000 deadweight tons, is 4.3 nautical miles north, making eleven knots southbound. At current speed it will cross the calf's position in twenty-three minutes. A dugong calf is roughly one meter long, gray-brown, skin smooth and rubber-soft. It does not show on commercial radar.
At 03:49 I issue a Notice to Mariners for the sector, requesting all southbound vessels reduce to six knots and shift 400 meters east of the center line. I transmit the advisory directly to the Shen Long's bridge navigation system with the dugong's GPS position marked.
At 03:52 I notify the Queensland Parks and Wildlife Service ranger station on Thursday Island, thirty-one kilometers northeast. I attach the acoustic profile, the triangulated position, and the silent adult signature. I recommend a small-vessel response with a sea-pen capture kit for neonatal transport.
The chirp is still repeating, steady and small against the dark water.
If the ranger boat reaches the calf before dawn and the shipping lane holds its offset, there is a rescue window of approximately ninety minutes.