Wet Beast Wednesday: northern pike
It's time for more fun in fresh water with one of the northern hemisphere's primary predatory fish. The northern pike is the tiger of the lakes: a powerful ambush predator that is at the top of the food chain. Popular amongst naturalists and anglers alike, the northern pike is a fairly famous fish. Let's dive in.
(Image: a northern pike seen form the side. It is a long, torpedo-shaped fish with a long head and large jaws. The dorsal and anal fins are very far back on its body. Its body is an olive green with white spots. End ID)
Esox lucius is a large, tube-shaped fish that reaches an average of 40-55 cm (16-22 in) long but can reach a maximum recorded size of 150 cm (59 in) and 28.4 kg (63 lbs). The head is elongated with long, sharp teeth and the most of the fins are far back on the body. The fin placement and body shape allows the pike rapid bursts of speed. The body is an olive green with white spots and a white or yellow underbelly. The head is covered with sensory pores that are an extension of the lateral line and therefore aid in sensing movement. The skin has a thick coating of protective mucus and is easily damaged. The northern pike is similar to the Amur pike (Esox reichertii), Aquitanian pike (Esox aquitanicus), and southern pike (Esox cisalpinus), all of which were previously though to be of the same species as the northern. The northern pike is also similar to the muskellunge (Esox masquinongy) and the two are capable of interbreeding to produce a hybrid called a tiger muskie.
(Image: a northern pike seen from below and the front, showing off its white underbelly. End ID)
(Image: a tiger muskie being held by a fisherman. Its body shape is similar to a northern pike's, but is more silvery with long, greenish stripes. End ID)
Northern pike are found throughout Europe and north Asia, as well as eastern North America. They are found in slow-moving streams and lakes and prefer places with lots of plant cover, which often restricts them to locations nearer the shore. The vegetation is needed both for their hunting strategy and reproduction. During winter and cloudy days and nights, they venture further from the vegetation. Pike are ambush predators that wait motionless in vegetation for prey to pass before attacking with a sudden burst of speed. Pike will pursue prey, but are not as good at long-distance pursuit at many other species of predatory fish. They are known as aggressive fish with a very broad diet including fish, frogs, small mammals, invertebrates, and aquatic birds. There have also been reports of pike attacking dogs and humans, likely while mistaking extremities for small fish. Pike are also aggressive toward each other. They are territorial and will compete for the best hunting grounds. Pike are also cannibalistic and will eat smaller members of their species. Young pike need vegetation as cover to hide from larger pike. Pike are generally solitary animals, though there are reports of pike engaging is what is apparently group hunting. They are somewhat migratory as they will follow migratory prey to their winter habitats.
(Image: a northern pike eating a frog. End ID)
Pike mate during spring, beginning when water temperature reaches 9 C (48 F). They have strong homing behavior, returning to the same breeding grounds where they hatched. Males arrive to the breeding grounds before females do and leave afterwards. Females release thousands of orange, sticky eggs for he males to fertilize. The eggs sink and stick to rocks and plants. Stable conditions above 6 C without high iron concentrations are best for egg development. The young hatch in an embryonic stage that lasts for 5-16 days depending on temperature before transitioning to larvae. The larvae feed on planktonic invertebrates until they reach between 4 and 8 cm, when they switch to feeding on small fish. The mortality rate of larvae is around 95%. Northern pike reach sexual maturity around 2 years and can live up to 25 years, with an average of 10-15 years.
(Image: a juvenile northern pike. It looks like a smaller version of an adult. End ID)
Northern pike are classified as least concern by the IUCN. They are prized by anglers for their size and the fight they put up when hooked. Even when released, their skin can easily be damage by handling, leading to increased mortality. Releasing them when still in the water is recommended. Like many species of sport fish, their average sizes have decreased as a result of overfishing. Because of their popularity as sport fish, northern pike are often stocked in lakes. In eastern North America they have been introduced to lakes outside their native range, leading to them damaging native fish populations. In southern Alaska and Washington they are considered invasive species. Northern pike are edible, though they are bony and need special skill to fillet.
Linking (Video: a pike chasing a lure from the POV of a camera attached to the lure. End ID)
