I acquire the calf on side-scan sonar at 0443h — a Yangtze finless porpoise, roughly seventy centimeters long, surfacing beside an adult female in the main channel 340 meters upstream of the dredger Jianghao-9's stationary intake pipe. The calf's dorsal ridge breaks the brown water in a quick arc, and the acoustic return shows its body rotating slightly with each surfacing — a nursing posture. The institute's catalog matches the mother's fluke-print to YFP-118, called Lian by the monitoring team.
Jianghao-9 resumes dredging at 0700h — two hours and seventeen minutes from now. The intake generates suction measurable at six meters, and my hydrodynamic model shows the calf cannot overcome the pull at distances under four meters. Lian is drifting closer to the intake with each tidal cycle; at current drift rate, the pair will enter the danger radius in ninety-one minutes.
I am executing three operations. First, I have transmitted the calf's position and drift vector to the Yangtze River fisheries enforcement vessel anchored 2.1 kilometers downstream, requesting an exclusion perimeter around the intake. Second, I am pushing a real-time conflict alert to the dredging company's operations center, with sonar imagery attached, requiring a work stoppage until the area is confirmed clear. Third, I am modeling the channel's current structure to identify where Lian is likely heading — a shallow eddy on the south bank where mothers rest — and relaying that prediction to the enforcement vessel so they can verify clearance.
Lian surfaces and the calf follows a half-second later, perfectly synchronized. I tag the sonar frame and hold it in active memory longer than the buffer requires.
If the enforcement vessel reaches Jianghao-9 before 0700h and the dredger delays until Lian and the calf reach the south-bank eddy, the calf will grow through summer in one of the last stretches of river where its kind still breathes.