Фенологія нересту плоскирки (Blicca Bjoerkna) у біотопах природного заповідника «Дніпровсько-Орільський» залежно від сезонної зміни температур

This paper examines the relationship between climatic conditions and the phenology of spawning of the white bream Blicca Bjoerkna (Linnaeus, 1758) in natural habitats of the "Dnipro-Orilskiy" Nature Reserve. The characteristic of spawning distribution is symmetric, as the asymmetry coefficients do not significantly differ from zero. The distribution of the timing of spawning and its duration are also characterized by excesses, which do not significantly differ from zero alternatives. Analysis of meteorological data for the period of study allowed us to determine the trends in temperature variation, which correlate with the temperature of the water. Spawning events in any given year take place entirely within an upward temperature progression that can be accurately described by a linear equation in the form: Y = b + a • x, where Y – ten-day average temperature; x – the order of decades for I–VI months of the year, a and b – the parameters of the equation. The same equation can be used to describe downward movements in the temperature for decades during the VII–XII months of the year. Regression parameters and coefficients of determination have the following environmental sense. For the ascending temperature branch the regression coefficient b will decrease in proportion to the increase in the contrast between winter and summer temperatures. Due to the fact that linear approximation is a certain generalization of the sinusoid natural course of temperature, it should be borne in mind that the highest summer temperatures are close to the change in direction in the course of temperature from increase to decrease. Therefore, the coefficient b will largely depend on the minimum winter temperatures and should be interpreted as a marker of the coldness of the winter. This interpretation is all the more justified because we are concerned here with assessment of the impact on fish spawning, and the processes that precede spawning events clearly have importance for their explanation. Changes in the direction of the course of temperature which occur after spawning and have no value in explaining spawning. If we consider coefficient b beyond the environmental context, then certainly this figure depends on the coldness of the winter and equally on the warmness of the summer. Similar considerations lead us to interpret the coefficient b of a descending branch as a marker of the warmness of the summer. Comparison of the ascending temperature branch of the current year and