Features of the Life Cycles of Copepods in Different Areas of Lake Onego

The study of the features of the life cycle of planktonic copepods, which allow species to adapt to the impact of various environmental factors, is one of the topical areas of ecological evolutionary developmental biology (Eco-Devo). Based on the analysis of the data of long-term research, the features of the ontogeny of common Copepoda species (Limnocalanus macrurus Sars, 1863, Eudiaptomus gracilis (Sars, 1863), Mesocyclops leuckarti (Claus, 1857), Thermocyclops oithonoides (Sars, 1863) in plankton of Lake Onego were studied. Comparison of the characteristics of the life cycles of species from different areas of the lake made it possible to identify the influence of the temperature factor. The thermal regime determines the timing of development of age stages of crustaceans in regions. The earliest dates for the onset of reproduction and development were noted in Petrozavodsk Bay and the Kizhi Skerries region. In spring, in Petrozavodsk Bay, the onset of development was observed 2–3 decades earlier for L. macrurus and 1–2 decades earlier for E. gracilis, M. leuckarti, and T. oithonoides than in the central region of the lake. In June, lower average quantitative indicators of copepods in Petrozavodsk Bay were recorded than those in the central region of the lake. According to our data, there were no noticeable changes in Copepoda abundance in Lake Onego from 1988 to 2020. This can be explained by the preservation of natural conditions for the habitat of crustaceans in Lake Onego.