The Northern pike Esox lucius is in the family Esocidae, a predatory group of freshwater fishes. The remaining members of Esocidae being the pickerels Esox americanus and Esox niger, the megapredatory Muskellunge Esox masquinongy, and the Amur pike Esox reicherti. There is some debate on whether the Amur pike is a distinct species from or a sub-species of E. lucius. For the purposes of this article we will treat E. reicherti as the same species as E. lucius. Due to their voracious appetite and large size, Northern pike are a popular game fish for recreational anglers in North America and Europe. Esocids as a family date back to the Cretaceous period. The Paleocene fossil Esox tiemani is most similar in morphology to the Northern pike indicating that E. lucius is the least derived of the extant species in the family Esocidae and has common ancestors that date back 62 million years.
12-14" juvenile Northern pike from the Kankakee River, Illinois. Photo credit: Uland Thomas
1.3 meter (50") Northern pike from Manitoba, Canada.
Photo credit: Jerry Dunlop, www.dunlopfishing.com
1.3 meter (50") Northern pike from Stark Lake, Northwest Territories, Canada. Photo credit: Nathan Musclow
Juvenile E. lucius feeding on a trout (salmonidae) fingerling in captivity. Notice how the young pike shifts the prey in the mouth to swallow the prey head first.
Video credit: Bernt René Voss Grimm
E. lucius is an elongate, tube-shaped fish with the median fins set on the posterior potion of body. The caudal fin is forked with the ends rounded. Pectoral fins are located ventrally just posterior the operculum (gill cover). Pelvic fins are located ventrally on the middle region of the body. The snout has a duck-bill shape and the mouth is lined with sharp canine teeth on the lower jaw and small fine teeth on the upper jaw. Adults have white or yellow bean shaped spots against a dark green or brown background on the lateral portions of the body. A solid dark green or brown coloration covers the dorsal region of the body. The ventral region from the snout to the anal fin is pearl white. The fins have dark black markings against a yellow, red, or orange background. Fingerling pike often have a tiger-like pattern with yellow lines against a green background. Diagnostic features include 1.) cheek fully scaled and half scaled opercle and 2.) five to six submandibular (lower jaw) pores. Northern pike can attain lengths of up to 1.5 meters and weigh 30+ kilograms.
Spawning occurs in late winter or early spring when the water temperature is on average 6-14ºC, depending on the region. Males reach sexual maturity at 1-2 years of age (16-18 inches in length) and females at 2-3 years of age (20-22 inches in length). The onset of sexual maturity occurs fastest in regions where pike have highest growth rates. Like most other bony fishes (Osteichthyes), Northern pike exhibit external fertilization in which the eggs are fertilized and develop outside of the females body (termed oviparous). During the month long spawning season a single female is accompanied by multiple males. Females release eggs in vegetation and males fertilize the eggs by releasing sperm and using the caudal fin to mix the gametes. Besides the actual spawning event, adult pike show no parental care. Eggs hatch into yolk-sac embryos 12-14 days after spawning. The new-born pike attach to vegetation and absorb the yolk for about 10 days. After which, the pike become free-swimming and begin exogenous feeding on zooplankton. By the time other fishes are spawning in late spring or early summer, the fingerling pike are already a couple inches in length and can prey upon the spring/summer recruitment. Certain European populations of northern pike are unique in that they are anadromous, migrating from the Gulf of Bothnia into freshwater rivers to spawn, much like well-known salmon (salmonidae) runs.
Like most fishes, pike have what is called indeterminate growth, meaning they will continue to grow throughout the entire lifespan. Growth tends to increase rapidly in young fishes and slows abruptly after sexual maturity. On average, pike live around 7 years in the wild, the equivalency of a meter long pike. However, larger pike can be as old as 25 years old. In captivity, pike have lived to 75 years of age.
Distribution & Movements
Northern pike, as is evident in the common name, are distributed in the northern hemisphere of North America, Europe, and Asia. The distribution of the Northern pike is unique in that it has the most widespread distribution of any exclusively freshwater fish. Burbot Lota lota is another freshwater species with circumpolar distribution, though, not as widespread as the Northern pike's. Pike have been intentionally introduced in many non-native countries including Australia, New Zealand, Madagascar, Ireland, and Spain. Due to their predatory nature, pike have also been introduced in historically absent areas of native countries to support sport-fishing and to control over-population of prey species.
Northern pike are temperate, cool-water species that can be found in just about every type of freshwater habitat. Prime habitat is vegetated areas of lakes and backwaters of rivers with plenty of forage. Adults lurk within and around vegetation waiting to ambush prey with quick bursts of speed. Larval pike also utilize vegetation as nursery grounds and as pike grow juvenile pike remain near vegetation to hide from larger piscivores and ambush prey.
Food & Feeding Habits
Northern pike are chiefly piscivorous, but are opportunistic predators that will feed on crustaceans, amphibians, birds, small mammals, and even other pike. A Lie-in-wait technique of prey capture is evident by the anterior morphology of Northern pike. Like the oceanic barracudas (Sphyraenidae), Northern pike have elongate bodies with the median fins set on the posterior portion of the body and a low aspect ratio caudal fin. Fishes with this type of body plan can rapidly accelerate in short bursts of speed. A large gape and expandable stomach give pike the ability of swallowing large prey. Sharp teeth allow northern pike to capture prey and maneuver the prey in the mouth so that the prey item is swallowed head first. This is critical as a large number of fishes have sharp spines in their fins, which would prevent swallowing if not ingested head first. The eyes of pike are highly mobile and can locate fast moving prey. Grooves along the snout just anterior the eyes allow pike to judge distance when locking onto prey. The lateral line system, a line of pores along each side of the body and around the face, detect distortions in the water column around the fish providing an additional tool for prey location. The lateral line system is so effective that blind pike have been documented surviving in the wild.
Larval and juvenile pike can fall prey to a great number of animals including other fishes, mammals, birds, and insects. However, as pike grow to adulthood they quickly earn rank in the top of the food chain with limited predators, humans being one of the very few.
Economic Importance for Humans
Esox lucius is a popular food for some cultures as pike can grow large and contain a good amount of meat. However, pike also contain numerous small bones (difficult to fillet) and can harbor large quantities of parasites. So, pike need to be cooked thoroughly if eaten. The countries with the largest commercial catch of Northern pike in 1999 were Finland and Russia. Northern pike are also an important game fish and are stocked extensively in North America and Europe for sport-fishing. Anglers use fast moving artificial lures like spinner-baits to trigger the predatory instincts of pike. Live baits such as suckerfish (Catostomidae) are also popular baits to catch large pike.
Threats & Conservation Status
Pike are a least concern speces according to the IUCN's red-list. The widespread distribution, lack of predators, and popularity as a game fish ensure the Northern pike's existance for the foreseeable future. Although, there is one threat to Northern pike, the destructon of spawning habitat. Wetland and marsh habitat have been greatly reduced due to development in the native range of the Northern pike.
Bosanko, Dave. 2007. Fish of Michigan Field Guide. Adventure Publications, Inc., Cambridge, Minnesota.
Cooke, Fred, Hugh Dingle, Stephen Hutchinson, George Mckay, Richard Schodde, Noel Tait, & Richard Vogt. 2008. The Encyclopedia of Animals: A Complete Visual Guide. University of California Press, Berkeley and Los Angeles, California.
Freyhof, J. & M. Kottelat. 2008. Esox lucius in IUCN 2012. IUCN Red List of Threatened Species. Version 2012. <www.iucnredlist.org>.
Helfman, Gene S., Bruce B. Collette, Douglas E. Facey, & Brian W. Bowen. 2009. The Diversity of Fishes: Biology, Evolution, and Ecology. 2nd edition. Wiley-Blackwell West Sussex, United Kingdom.
Page, Lawrence M., & Brooks M. Burr. 2011. Peterson Field Guide to Freshwater Fishes of North America North of Mexico. 2nd edition. Houghton Mifflin Harcourt, New York, New York.
Raat, Alexander J.P. 1988. Synopsis of Biological Data on the Northern Pike. Food and Agriculture Organization of the United Nations. No. 30 Rev. 2.