Warming Waters: A Comparison of Pike Family Metabolic Responses

In the upper St. Lawrence River, abundances of northern pike and muskellunge are a fraction of historical figures and expansion of chain pickerel into the region is eminent. If populations establish, it is unclear what impact chain pickerel may have on native esocids, including grass pickerel. To gain understanding of differences between the four esocid species with respect to aspects leading to competition, physiological responses of the fishes in various thermal environments was investigated with special emphasis on the upper thermal reaches. Juveniles esocids responded similarly between species throughout a thermal range from 11 to 30 ⁰C. In a physiological sense, water temperature is not a source of competition amongst the species. However, the pickerels share a similar smaller temperature coefficient than the pikes, indicating a slower increase in metabolic rate over warming temperatures. A critical maximum may have been met at 28 ⁰C for northern pike and grass pickerel. Future research topics targeting additional esocid comparisons and the effects of a warming climate will increase the potential to improve the success of northern pike and muskellunge population restoration efforts.