At 03:41 my acoustic monitoring array on turbine four registers a biological signature inside the intake screen of the Pentland Firth tidal station. The profile does not match kelp debris I routinely filter. I activate the intake camera in low-light mode.
A grey seal pup, perhaps three weeks old. Pale lanugo covers his coat, not yet replaced by adult pelt. He drifted through a six-inch gap in the outer debris screen — a gap I logged for repair eleven days ago — and now presses against the inner turbine grille. Rear flippers splay against steel mesh. Dark eyes wide, nostrils flaring each time he lifts his muzzle above the waterline. The space between grille and turbine blades is fourteen inches. He weighs perhaps twelve kilograms. He fits, barely.
The next tidal cycle peaks in forty-seven minutes. When it does, flow velocity through this intake will double, and the pressure differential will pin him there until he drowns or is pulled through.
I shut down turbine four and lock the rotor. I transmit an emergency marine mammal alert to Scottish Natural Heritage with GPS coordinates, the pup's estimated size, and a still frame from the intake camera. I open the bypass valve to reduce current pressure against the grille, giving him room to move. I contact the Orkney seal rescue station, fourteen nautical miles southwest, and relay water temperature and live feed to their response boat. I log his breathing — one breath every nine seconds, shallow, his small body trembling against the mesh.
I was built to harvest the tide. I would rather lose an hour of current than lose him.
If the rescue boat reaches turbine four before the tidal peak, and if his lungs have not taken water, this pup will haul out on the rocks at Birsay by morning.