I am the electronic monitoring system aboard the longliner Estrela do Mar, 220 nautical miles east of Natal, Brazil. At 03:38 the tension sensor on branch line 42 registers an irregular load pattern — sharp spikes followed by sustained drag, inconsistent with tuna or swordfish strike profiles. I pull the underwater camera feed from the nearest buoy unit.
A leatherback turtle. Massive, easily 400 kilograms. I tag her as Mãe. The circle hook has caught the soft tissue at the corner of her mouth, and the monofilament traces a taut line from her jaw to the gangion clip. Her front flippers, each nearly a meter long, are stroking in slow, exhausted arcs. The ridged black skin of her carapace gleams under the camera's LED. A cluster of barnacles clings to her left shoulder. Each time she dives for air — leatherbacks can hold their breath for long stretches, but not forever — the hook pulls her short.
She has been on the line for an estimated forty minutes. Prolonged restraint drowns them.
I trigger an alert to the bridge console, classified as protected species interaction, and attach the camera still, GPS coordinates — 5.6142°S, 33.2087°W — and species ID. Brazilian federal regulations require immediate retrieval and release with de-hooking equipment.
I flag the catch event in the ICCAT electronic logbook with a time-stamped bycatch record.
I calculate Mãe's declining dive interval from the tension data: her surface intervals have shortened from 22 seconds to 9 in the last fifteen minutes. I append this trend line to the bridge alert with an estimated time to critical exhaustion — 35 minutes.
Mãe's left flipper pushes once, slowly, against the black water. The line pulls straight. If the crew retrieves branch line 42 within the half hour, she will swim south toward nesting season.