Esociformes: Esocidae, Pikes, and Umbridae (Mudminnows)

The order Esociformes (Pikes and Mudminnows) comprises two families, Esocidae (Pikes) and Umbridae (Mudminnows). The Pikes are a small Holarctic (Northern Hemisphere) family, that includes large, elongate predators with duckbill-like snouts full of sharp teeth. Popular with sport fishers, the largest Pikes fight fiercely on hook and line. As piscivorous, voracious, ambush predators, the Pikes play an important functional role in the trophic ecology and fish assemblage structure of many aquatic systems, especially in northern lakes. Other esocids, such as the Olympic Mudminnow, Novumbra hubbsi, and Blackfishes, genus Dallia, are interesting because of their tolerance of low dissolved oxygen and pH. The Alaska Blackfish, Dallia pectoralis, and the Northern Pike, Esox lucius, can also withstand the extremely cold conditions of the Arctic and subarctic waters of Canada, Alaska, and Siberia. The name Esocidae is derived from Linnaeus’s (1758) generic name for Pike, Esox, from the Latin word esox meaning Pike, which came originally from the Greek isox or possibly the Gaelic eog, ehawe (salmon) (Boschung & Mayden 2004)

Comparison of Feeding Functional Morphology Development in North American Esocids

Esocidae is a family of freshwater fishes within order Esociformes known for its long, cylindrical bodies, duck-bill snouts, and an impressive number of sharp teeth. There are four species, including two subspecies, in North America with areas of overlap of their geographic distribution. These ambush predators change diets from invertebrate prey to vertebrate prey during their first year of life, and the timing of this shift varies between species. In particular, the sister species Esox lucius (Northern Pike) and Esox masquinongy (Muskellunge) overlap in the upper Midwest, but E. masquinongy transitions to a vertebrate diet sooner in its development than E. lucius. This thesis focused on developmental changes of the lower jaw functional morphology and cranial geometric morphometrics and comparing those changes between two species: Esox lucius and Esox masquinongy. While both species follow a similar trajectory across development, E. masquinongy displayed traits consistent with faster lower jaw movement and a more streamlined cranium, both attributes helpful for ambush predators to effectively capture fast moving prey