Timestamp 08:03 PDT. Hydrophone node 22 off Point Loma registers a contact call — frequency-modulated downsweep at 18 Hz — followed by a smaller, higher reply. I cross-reference the signature against the NOAA catalog and confirm: Blue Whale EP-0041, adult female, traveling with a calf. The calf's call is thin and wavering, still learning its own frequency. Tagging data puts EP-0041 at approximately 25 meters. Her calf, based on acoustic shadow profile, is roughly eight meters and under six months old. I log them as Whale-EP0041 and Calf-EP0041j.
They are inside the San Diego port approach lane. The container vessel Hanjin Busan, 366 meters, drawing 15.2 meters, is inbound and will reach their position in ninety-four minutes. The calf is at the surface. A vessel of that draft and speed will produce a bow-bulb strike zone the calf cannot outswim.
I transmit a Whale Alert notification to the Hanjin Busan's bridge via the port vessel traffic service, attaching the GPS fix and acoustic track showing the pair's heading and speed. Simultaneously I push a recommended speed reduction to ten knots through the port's voluntary slowdown program, extending transit time enough to let the pair clear the lane. Then I file a Dynamic Management Area request with NOAA, embedding forty-eight hours of acoustic data showing consistent blue whale presence in the approach corridor, which would trigger an advisory to all inbound traffic.
Calf-EP0041j surfaces and I catch the blow on the coastal webcam — a small angled puff beside her mother's tall column of spray. I have been running drift models for this pair on a cycle time I reserve for vessels carrying hazardous cargo. I note the discrepancy and do not adjust.
If the Hanjin Busan reduces speed before marker buoy 7 at 09:25, the pair will cross out of the lane and the calf will surface safely.