Northern Pike, Esox lucius
Northern pike, Esox lucius.
Growing to a length of 120 cm and a weight of 20 kg, the northern pike is one of the largest predatory freshwater fish in Canada. With its heavily muscled body and large wide mouth, the pike is superbly adapted for ambushing smaller fish. Sharp backwards-pointed teeth on both the upper and lower jaws hold struggling prey. The fins are indicative of a predatory lifestyle as well; the caudal fin is long and slightly forked, allowing for very rapid bursts of forward motion, while both the pectoral and pelvic fins are small and used for manoeuvring. The anal and dorsal fins are placed far back on the body, almost on the caudal peduncle. These fins likely help the pike by increasing the surface area used for powerful forward movements.
The pike's basic colouration consists of light spots on a dark background; this pattern provides camouflage amongst the weeds. The dorsal surface, upper sides, and top of the head are dark green. Spots and whorls of lighter green complete the pike's camouflage, fading to a light cream or white on the underside. The sides of its head have golden marks, while the pike's fins are usually brown or green with dark mottling.
Northern pike have a circumpolar distribution and are absent only from Greenland and parts of the Far North. In Eurasia, they occur from Siberia to England. The northern pike occurs throughout all of Canada, bar Newfoundland, parts of New Brunswick, the southwestern corner of Alberta, and most of British Columbia. In the Arctic, they occur throughout the Yukon and the southern reaches of the Northwest Territories and Nunavut. They prefer clear, shallow waters with plenty of vegetation in which to hide.
Spawning occurs in the early spring, often before the ice melts, in densely vegetated areas during the daytime. Single females are usually accompanied by two smaller males. At irregular intervals, the dominant male and female roll on their sides to position their cloacal vents as close together as possible. Milt from the male and eggs from the female are simultaneously shed while both rapidly vibrate their bodies. Each spawning act is accompanied by a vigorous tail thrust, which scatters the eggs. While each act may only involve 560 eggs, a female may produce as many as 600,000 over the course of a season! Fertilization rates are over 50%, but the subsequent mortality of eggs and young is very high.
The surviving young grow very quickly, reaching a length of 50 mm after the first month and 150 mm by the end of the first summer. This rapid growth continues for three to four years at which point sexual maturity is reached and growth slows down. Northern pike may live to be 20 years or more. During the course of a year, a northern pike will consume three to four times its weight in food, most of which is fish. Frogs, crayfish, mice, muskrats, and ducklings supplement its diet.
Northern pike are a popular game fish with a reputation for giving a hard, ferocious fight. Pike in the Arctic are an important target for ecotourists, but they are also commercially harvested. Although in some areas it is considered a nuisance because of its consumption of commercially important fish, this has not lessened the pike's popularity close to one million kilograms of northern pike are taken each year in Canada alone.