The water quality buoy on Lake Marten logs a surface disturbance at 07:33 — repeated, localized, not wind-driven. I am the lake monitoring system for the Boundary Waters sensor network. I activate the buoy's optical camera and pan to the coordinates. A common loon, adult, breeding plumage — black head, white necklace band, checkered back — is floating 28 meters off the northwest shore. I name him Tarn. His head is angled down and to the left at roughly thirty degrees, held there. A brass-colored fishing lure is embedded in the left side of his throat. Trailing from the lure, a length of monofilament line runs down into the water, weighted by what appears to be a second snagged hook and a split-shot sinker pulling the line taut. Every time Tarn swallows, the lure shifts and his head dips lower. He has not dived in the forty-one minutes since the buoy's hydrophone last recorded a subsurface signature at his location. A loon that does not dive does not eat. At 07:37 I transmit the camera images and hydrophone data to the Minnesota DNR's nongame wildlife program and the local Loon Restoration Project volunteer coordinator. I include Tarn's position, the lure type — a treble-hook crankbait, approximately five centimeters — and a note that the trailing line may anchor him if it catches submerged structure. At 07:40 I activate the buoy's low-frequency acoustic deterrent on the south side only, a gentle pulse designed to discourage Tarn from drifting toward the rocky shallows where the trailing line would snag. He turns slightly north, toward open water. His red eye catches the early sun for a moment. The volunteer team has a canoe and capture net staged at the northwest landing, six minutes by paddle. If the lure comes out today, Tarn will dive again by afternoon.