Избираемые, оптимальные, пессимальные и толерантные температуры ветвистоусых раков Simocephalus vetulus (O. F. Muller, 1776)

Abstract

Temperature election and avoidance are investigated in Simocephalus vetulus (O.F. Muller 1776), caught during the vegetative season in the littoral of the Rybinsk Reservoir. The methodology for determining a thermotolerance range, a temperature zone of normal vital activity and pessimal temperatures, based on the data analysis of distribution of cladocerans in a thermal gradient installation, is proposed. The range of final elected temperatures (FET) (13.4–25.4 о С), corresponding to the optimum temperatures for growth and development of cladocerans, is indicated. The temperature zone of normal vital activity (>7.0 and <29.0 о С), pessimal temperature range (4.0–7.0 о С and 29.0–32.0 о С) and temperature limits of species tolerance (4.0–32.0 о С), coinciding with the field observations of S. vetulus populations, are calculated.