The Pike environment
Within the broad borders of the natural settlement of pike, there are areas with significantly different climatic features. It tolerates staying in warm parts of the temperate zone just as well, like the harsh conditions of the far north. But not only in relation to temperature, it exhibits considerable tolerance. Requirements for environmental factors such as light, electricity, pH, salinity, they are not limited by a narrow range of optimal values. Therefore, the distribution of pike in the waters covered by their geographical range is very even. They are found in rivers and lakes of all types, and also in the joints, brackish lagoons and even in the coastal zone of the Baltic Sea. They like slow lowland rivers with dead ends and oxbow lakes, but they are not lacking in the middle and upper reaches, where they reach the border of the land of trout, into the estuary area of cool streams with a significant slope of the bed and a fast current. When it comes to stagnant waters, warm ones seem to suit them the most, fertile reservoirs of low-lying regions, however, they find sufficient living conditions also in cold alpine lakes situated at an altitude 1500 m above sea level. Being a typical freshwater fish, the pike does not avoid brackish flood waters, where - for example in the Vistula and Szczecin Lagoon - it is one of the main components of the fish stock. It also occurs in the estuaries of the southern Baltic coast, in the fjords of southern Scandinavia, along the Danish coasts and around Bornholm, abolishing salinity 8 ‰ (Larsen, 1944).
On the one hand, low sensitivity to the physicochemical properties of water allows pike to use a very diverse environment, on the other hand, some biological features are a factor limiting its occurrence in the area of individual reservoirs. Obtaining food "from an ambush" requires habitats abundant in positions that well mask the position occupied by the predator. This role is best played by aquatic vegetation. The absence of pike in the river land of trout can be equally explained by the lack of vascular plants, such as excessively fast current or too low water temperature. Their distribution in the middle and lower reaches of the rivers depends on the distribution of plant clusters, among which they find suitable hiding places and an abundance of food. Such focus, located near the shores, they can be the starting point for possible excursions into the full-flow zone.
In still waters, plant distribution is primarily related to depth, and the factor limiting their occurrence is the inflow of light necessary for the photosynthesis process. Therefore, the coastal areas are the most overgrown, where in the shallows, groups composed of emerged plants dominate, forming dense stripes of bulrush. In places slightly deeper and sheltered from the wind, plants with floating leaves develop, and further in the depth there is an area of underwater meadows covered with submerged vegetation. The entire zone described, called littoral, it reaches the edge of the slope, which marks a sharp decline of the bottom towards the deepest part of the reservoir. Plants submerged, going beyond that edge, it can reach six meters or more below the surface - depending on the transparency of the water. Its range marks the border of the sub-habitat zone.
Shallow lakes provide the most favorable living conditions for pike, articular type, in which the literal takes up almost the entire underwater space. For the sake of the second, together with pike the dominant species, they got the fishing name of rope-pike lakes (Lynx. 12 A). The composition of the ichthyofauna associated with the plant zone is complemented by a roach, perch, skim, rudd and other small fish that provide the predator with an abundance of food.
Lynx. 12. The transverse section of a pond-type lake basin (A) and a deep lake (B): 1 - coastal zone, 2 - full water zone (pelagic), 3 - strive for this.