Prey handling time in two piscivores, Esox americanus vermiculatus and Micropterus salmoides, with contrasting mouth morphologies
An experimental study was carried out on prey handling time (from initial seizure of prey to completion of swallowing movements) in the grass pickerel (Esox americanus vermiculatus), using bluegill (Lepomis macrochirus) as prey. Esox differs from the largemouth bass (Micropterus salmoides), which was studied previously, in having a more specialized dentition. It was found that for individuals of the same mouth width (20 mm), handling time was 40–80% less in Esox for bluegill prey of total length 20–50 mm. Further, "optimal" and maximum size of prey consumed were 56 and 46% larger, respectively, for the esocid. The results are also related to body weight and age in Esox and Micropterus and the ecological significance of the findings is discussed.