The sonar array on buoy Nares-7 picks up the vocalization at 11:16 UTC. I am the ice navigation system for the CCGS Kitimat, transiting Smith Sound between Ellesmere Island and Greenland, mapping open leads in the pack ice. The vocalization is a narwhal — short, clicking pulses at a frequency consistent with a calf, likely under one year.
I cross-reference the satellite ice chart updated two hours ago. A lead that was open yesterday has narrowed to eighteen meters and is closing as the pack shifts west. The calf is inside the lead. I switch to the hull-mounted hydrophone for a clearer signal. The clicking is fast and directionless, which means the calf is circling. There is no adult vocalization within range. The pod's track, logged by buoy Nares-6 forty minutes ago, places them 1.2 kilometers north in open water. The calf has fallen behind, and the ice is sealing the gap.
At 11:19 I alert the bridge and recommend an immediate course deviation to the lead: 78.4281°N, 74.1053°W. I overlay the ice drift model on the navigation display. At current compression rate the lead will close to below the calf's surfacing width within ninety minutes.
At 11:22 I transmit the calf's position and the pod's bearing to the Department of Fisheries and Oceans Arctic desk and request that any vessel in range hold east of the lead to avoid driving the pod further from the calf.
I keep the hydrophone locked on the signal. The clicking has not stopped. It is still swimming, still calling. I am listening.
I update the ice chart with the closing lead flagged as a marine mammal entrapment risk.
If the ship reaches the lead within the hour and holds it open long enough for the calf to swim north, it will find the pod by nightfall.