The northern pike (Esox lucius), known simply as a pike in Britain, Ireland, Canada, and most parts of the USA, also called Jackfish or simply "Northern" in the Upper Midwest of the USA), is a species of carnivorous fish of the genus Esox (the pikes). They are typical of brackish and fresh waters of the Northern Hemisphere (i.e. holarctic in distribution).
Pike grow to a relatively large size; lengths of 150 cm (59 in) and weights of 25 kg (55 lb) are not rare. The average length is about 70–120 cm (28–47 in). The heaviest specimen known so far was caught in 1983 at an abandoned stone quarry in Germany, where the species is known as a Hecht. She (the majority of all pikes over 8 kg or 18 lb are females) was 147 cm (58 in) long and weighed 31 kg (68 lb). The longest pike ever recorded and confirmed was 152 cm (60 in) long and weighed 28 kg (62 lb). A pike of 60.5 in (154 cm) was caught and released in May 2004 in Apisko Lake, Manitoba.
Historic reports of giant pike, caught in nets in Ireland in the late 19th century, of 41–42 kg (90–93 lb) with a length of 173–175 cm (67–68 in), were researched by Fred Buller and published in The Domesday Book of Mammoth Pike. Neither Britain nor Ireland has managed to produce much in the way of giant pike in the last 50 years, so substantial doubt exists surrounding those earlier claims. Currently, the IGFA recognizes a 25-kg pike caught by Lothar Louis in Lake of Grefeern, Germany, on October 16, 1986, as the all-tackle world-record northern pike.
Northern pike in North America seldom reach the size of their European counterparts; one of the largest specimens known was a 21-kg specimen from New York. It was caught in Great Sacandaga Lake on 15 September 1940 by Peter Dubuc. Reports of far larger pike have been made, but these are either misidentifications of the pike's larger relative, the muskellunge, or simply have not been properly documented and belong in the realm of legend.
As northern pike grow longer, they increase in weight, and the relationship between length and weight is not linear. The relationship between total length (L, in inches) and total weight (W, in pounds) for nearly all species of fish can be expressed by an equation of the form:
W = cL^b\!\,
Invariably, b is close to 3.0 for all species, and c is a constant that varies among species. For northern pike, b = 3.096 and c = 0.000180. (c=7.089 enables one to put in length in meters and weight in kg) The relationship described in this section suggests a 20-in northern pike will weigh about 2 lb (0.91 kg), while a 26-in northern pike will weigh about 4 lb (1.8 kg).
Pike angling is becoming an increasingly popular pastime in the UK and Europe. Effective methods for catching this hard-fighting fish include dead baits, lure fishing, and jerk baiting. They are prized as game fish for their determined fighting.
Lake fishing for pike from the shore is especially effective during spring, when the big pike move into the shallows to spawn in weedy areas, and later many remain there to feed on other spawning coarse fish species to regain their condition after spawning. Smaller jack pike often remain in the shallows for their own protection, and for the small fish food available there. For the hot summer and during inactive phases, the larger female pike tend to retire to deeper water and/or places with better cover. This gives the boat angler good fishing during the summer and winter seasons. Trolling (towing a fairy or bait behind a moving boat) is a popular technique.
The use of float tubes has become a very popular way of fishing for pike on small to medium-sized still waters. Fly fishing for pike is another eligible way of catching these fish, and the float tube is now recognized as an especially suitable water craft for pike fly-fishing. Also they have been caught this way by using patterns that imitate small fry or invertebrates.
In recent decades, more pike are released back to the water after catching (catch and release), but they can easily be damaged when handled. Handling those fish with dry hands can easily damage their mucus-covered skin and possibly lead to their deaths from infections.
Since they have very sharp and numerous teeth, care is required in unhooking a pike. Barbless trebles are recommended when angling for this species, as they simplify unhooking. This is undertaken using long forceps, with 30-cm artery clamps the ideal tool. When holding the pike from below on the lower jaw, it will open its mouth. It should be kept out of the water for the minimum amount of time possible, and should be given extra time to recover if being weighed and photographed before release. If practising live release, calling the fish "caught" when it is alongside a boat is recommended. Remove the hook by grabbing it with needle-nosed pliers while the fish is still submerged and giving it a flip in the direction that turns the hook out of the mouth. This avoids damage to the fish and the stress of being out of water.
In Finland, catching a kymppihauki, a pike weighing at least 10 kg (22 lb), is considered the qualification as a master fisherman.
Many countries have banned the use of live fish for bait, but pike can be caught with dead fish, which they locate by smell. For this technique, fat marine fish like herring, sardines and mackerel are often used. Compared to other fish like the eel, the pike does not have a good sense of smell, but it is still more than adequate to find the baitfish. Baitfish can be used as groundbait, but also below a float carried by the wind. This method is often used in wintertime and best done in lakes near schools of preyfish or at the deeper parts of shallow water bodies, where pike and preyfish tend to gather in great numbers.
Pike make use of the lateral line system to follow the vortices produced by the perceived prey, and the whirling movement of the spinner is probably good way to imitate or exaggerate these. Jerkbaits are also effective and can produce spectacular bites with pike attacking these erratic-moving lures at full speed. For trolling, big plugs or softbaits can be used. Spoons with mirror finishes are very effective when the sun is at a sharp angle to the water in the mornings or evenings because they generate the vibrations previously discussed and cause a glint of reflective sunlight that mimics the flash of white-bellied prey. Most fishermen tend to use small lures, but often that is not advisable because pike have a preference for large prey. When fishing in shallow water for smaller pike, lighter and smaller lures are frequently used. The humble 'woolly bugger' fly is a favourite lure among keen fly fisherman of the southern hemisphere.