The land of trout
The nature of the land of trout is largely influenced by climatic conditions and the decline of the watercourse; its inherent attribute is pure, cool water well saturated with oxygen. In our climatic conditions, the land of trout is formed mainly in mountain and foothill areas. Relatively large decline (often over 10 %) it directly influences the formation of a hard bottom – gravel, rocky, less often sandy or clayey – devoid of marsh sediments. Dna, which, in combination with the appropriate horizontal and vertical shape of the bearing, guarantees adequate oxygenation of the water. The maximum water temperature varies according to the drop ratios and can be determined by limit values 16-18-20 °C. Depending on the amount of water flow, trout can have different types of watercourses, starting from streams through streams to rivers. Natural watercourses are usually meandering, with a rich vertical shape and an abundance of coastal vegetation.. As a result of this formation, there is an abundance of various hiding places used by fish.
Only specially adapted fish can live in such harsh conditions, Therefore, the species composition of trout waters is poor. Only the brown trout and the bullhead bullhead can survive in the extreme conditions of the high mountain stream, to which gradually (in the lower parts) spring and rainbow trout are included, bullhead bullhead and slips and minnows even lower. In the lowest parts of the land, trout join the group of accompanying fish: grayling, gudgeon, chub, fir tree, sometimes also a piggy, brzana, burbot and eel.
The nutritional value of trout waters is relatively low compared to other types of waters. It is caused by a whole set of factors (cold, very fast water, poor in food, similarly poor in food bottom, the shortest growing season, etc.). The range of basic nutrients is also quite limited, and this applies to both benthos (larvae of two-environmental insects – a shot, gammarus, caddisflies), as well as food falling into the water (mature insects).
The breeding value of trout waters is very variable, depends on the current hydrological conditions (mass and uniformity of flow), climatic (length and average temperature of the growing season) and inheritance relations (participation of quiet parties, with better nutritional conditions, and a fast-paced party). It is generally accepted, that mountain rapids with extremely high descents and the harshest climatic conditions are the poorest.
Down the watercourse, with the smoothing of the slope and the gradual improvement of the climatic conditions, the fertility of trout waters increases. This causes an increase in the biomass of organisms, as well as enriching the species composition.
The following examples show the diversity of the fertility of watercourses: on 1 km of the mountain zone of the Nitra River (Slovakia) fall 323 trout, while on the same piedmont stretch there are them 1603; a five-year-old trout from a high mountain stream (High Tatras) only reaches 14 Cm, and a trout of the same age living in a dam reservoir (Hnilicki reservoir) it is four times larger: ma 56 Cm.
The specific quantitative status of trout in Central European conditions is very variable, because apart from the objective factors presented above, it is also determined by a set of subjective factors (restocking and catching proportions, protection and others). Under average conditions, we can take approximate values:
– in more severe climatic conditions – 400-600 pcs / km,
– under moderately favorable conditions – 700-900 pcs / km,
– under very favorable conditions, even over 1000 pcs / km.
