Esox lucius/northern pike

Description:

Northern pike are most often olive green, shading from yellow to white along the belly. The flank is marked with short, light bar-like spots and there are a few to many dark spots on the fins. Sometimes the fins are reddish. Younger pike have yellow stripes along a green body, later the stripes divide into light spots and the body turns from green to olive green. The lower half of the gill cover lacks scales and they have large sensory pores on their head and on the underside of the lower jaw which are part of the lateral line system. Unlike the similar-looking and closely related muskellunge, the northern pike has light markings on a dark body background and fewer than six sensory pores on the underside of each side of the lower jaw. Drawing of Esox lucius A hybrid between northern pike and muskellunge is known as a Tiger Muskellunge (Esox masquinongy × lucius or Esox lucius × masquinongy,[2] depending on the sex of each of the contributing species). In the hybrids, the males are invariably sterile, while females are often fertile, and may back-cross with the parent species.[3] Another form of northern pike, the silver pike, is not a subspecies but rather a mutation that occurs in scattered populations. Silver pike, sometimes called silver muskellunge, lack the rows of spots and appear silver, white, or silvery-blue in color.[4] When ill Silver pike have been known to display a somewhat purplish hue, long illness is also the most common cause of male sterility. In Italy, the newly discovered species Esox flaviae ("southern pike") was long thought to be a color variation of the northern pike, but was in 2011 announced to be a species of its own

Habitat:

Pike are found in sluggish streams and shallow, weedy places in lakes, as well as in cold, clear, rocky waters. Pike are typical ambush predators; they lie in wait for prey, holding perfectly still for long periods and then exhibit remarkable acceleration as they strike. In short, they will inhabit any water body that contains fish, but suitable places for spawning are essential for their numbers. Because of their cannibalistic nature, young pike need places where they can take shelter between plants so they are not eaten. In both cases it comes down to a rich submersible vegetation nearby. Pikes are seldom found in brackish water, except for the Baltic Sea area. Pike are known to prefer water with less turbidity but that is probably related to their dependence on the presence of submersible vegetation and not to their being a sight hunter.