Density, Size, and Foods of Larval Northern Pike in Natural and Artificial Wetlands

Abstract

Larval northern pike Esox lucius were sampled in natural and artificial wetlands associated with Conesus Lake, New York, on 25 April, 8 May, and 26 May 1992. Larval northern pike population densities declined significantly between the first (25 April) and second (8 May) sampling periods, indicating mortality or emigration from the wetlands; only two northern pike were captured on 26 May. Larval northern pike population densities were higher in artificial wetlands on 25 April, but on 8 May no difference could be detected. Mean total length of larvae was greater in artificial wetlands on 25 April and 8 May. Larval northern pike began feeding at approximately 15 mm total length. No difference in number of food items eaten was detected between natural and artificial wetlands; however, percentage of copepods, the taxa most commonly eaten, was higher in northern pike stomachs from natural wetlands. Cannibalism was observed in 1 of the 76 stomachs examined and constituted the only vertebrate food item found. Artificial wetlands were comparable or superior to natural wetlands as northern pike spawning and rearing habitat.