Smoke screen foraging: an observation of an unusual foraging behavior of the northern pike, Esox lucius.

Abstract

The foraging behavior of the northern pike is well documented. Northern pike often remain motionless while waiting for prey, a strategy known as lie-in-wait. Sometimes northern pike will cruise weed lines and mudflats in search of prey. When prey is encountered, the northern pike often initiates its fast-start attack, a high-powered burst of acceleration from a stationary or near resting position. In the initial stages of attack, the northern pike contorts its body into an S-shape, with median fins erect. Then large-amplitude movements are achieved with its long and streamlined muscular body, where the increased surface area of the erected posteriorly-positioned median fins propels and thrusts the fish forward toward the prey. Herein, we document an unusual foraging behavior of a northern pike approaching a fishing lure, an observation that was video-recorded while ice fishing on Deep Creek Lake, a reservoir in the Youghiogheny River drainage of western Maryland. The 68.6 cm (27 in.) TL northern pike approached and hesitated at about 15 cm from the lure, then paddled the bottom sediment with an alternate rowing motion of its left and right pectoral fins. This fin-churning motion created a large cloud or plume of sediment. The pike, while completely hidden in the expanding sediment plume, swam forward and then upward to engulf the lure. The use of a sediment plume during foraging is similar to a military maneuver known as a smoke screen, thus we label this unusual behavior as smoke screen foraging.