Offshore Prey Densities Facilitate Similar Life History and Behavioral Patterns in Two Distinct Aquatic Apex Predators, Northern Pike and Lake Trout

Northern Pike Esox lucius are important aquatic apex predators in freshwater ecosystems across the Canadian Boreal Shield. Although Northern Pike have historically been described as nearshore ambush predators, larger individuals have been anecdotally observed foraging in offshore habitats. We used two province‐wide data sets from Ontario, Canada, to investigate the degree to which Northern Pike are generalist predators by examining the influence of offshore prey fish densities on their life histories. To better understand whether the life history patterns observed were unique to Northern Pike or representative of aquatic apex predators generally, we compared Northern Pike life history and catch results to those of the Lake Trout Salvelinus namaycush , a well‐known pelagic apex predator. We found that the asymptotic lengths of both Northern Pike and Lake Trout were positively related to Cisco Coregonus artedi CPUE . Furthermore, both Northern Pike and Lake Trout occupied offshore habitat more frequently in lakes with greater Cisco CPUE s. Northern Pike early growth and mortality rates were negatively related to Cisco CPUE but positively related to Yellow Perch Perca flavescens CPUE , suggesting that Northern Pike undergo ontogenetic shifts to foraging on Ciscoes later in life. Although the growth and mortality of these predators were related to prey availability, variation in the CPUE s of Northern Pike and Lake Trout was best explained by physical lake characteristics. Our study suggests that Northern Pike and Lake Trout respond similarly to Cisco CPUE across the Canadian Boreal Shield, consistent with research reported for other aquatic apex predators. Results of this work collectively suggest that generalist behavior and large‐bodied life history strategies of Northern Pike are facilitated by the availability of Ciscoes.