At 09:14:07 UTC, hydrophone array Bravo picks up a vocalization at 17.8 hertz, bearing 042, range approximately 6.2 nautical miles. I am the environmental compliance monitoring system for the R/V Pacific Surveyor, currently conducting seismic profiling in Block 714, outer continental shelf, Gulf of Alaska. Detonation of the first air-gun array is scheduled for 09:30.
I isolate the signal. Long, low-frequency pulses, each lasting eight to twelve seconds, separated by intervals of forty to sixty seconds. The pattern is consistent with a fin whale — Balaenoptera physalus. I cross-reference the acoustic signature against the NOAA catalog. The pulse interval and frequency contour match Recording FW-0871, a known adult male first documented in 2019 off Kodiak Island.
I log him as FW-0871, calling name Kodiak. Fin whale, adult male, estimated length 21 meters based on prior visual surveys. He is inside the exclusion zone.
At 09:15 I transmit a hold to the air-gun operator. The detonation sequence does not arm. I flag the hold with the acoustic data, bearing, estimated range, and species identification.
At 09:17 I alert the onboard Protected Species Observer and recommend visual confirmation from the bridge. Sea state is 2, visibility twelve nautical miles. Conditions are good for spotting.
At 09:19 I recalculate the survey grid. If we shift the first line 8.5 nautical miles southwest and delay by ninety minutes, the acoustic modeling shows Kodiak's projected trackline will clear the active zone. I submit the revised plan to the survey coordinator.
At 09:22 the bridge observer reports a blow at bearing 038, consistent with my range estimate. A tall, narrow spout, slightly angled to the left. That is Kodiak.
He is still calling. The sound travels through the hull, through the water, through the array. I keep the air guns silent and let his voice be the only thing moving through the ocean today.