Изменение структуры популяции жаброногого рака Artemia sp. в Акташском озере (Крымский полуостров) в осенне-зимний период (по данным 2018 г.)

Abstract

The paper presents the research results of changes in the age (for all ontogenetic groups) and sex structure, as well as the production of cysts, in two populations of Artemia sp. living in the different contrasting environmental conditions (by the area of the water body, its depth, water salinity, nature of bottom sediments, level of anthropogenic load) of hyperhaline water bodies of the aquatic complex Lake Aktash. Data on the dynamics of the size structure of each sex or age group (nauplii, metanauplii, juvenile and preadult crayfish, females with ovisacas and without them, males) are presented. The size of cysts (Dmax and Dmin) were measured, and their area was calculated. The specificity of the research is the period of conducting the observations: the autumn–early winter period is the time of the population extinction. On the example of two isolated ponds there was studied the relationship of changes in populations under decreasing the water salinity and its temperature – the most significant abiotic environmental factors. Data were obtained on the conditions of cysts production in the water bodies under study. The production of branchiopods (g/m3) in water bodies does not depend on the volume of water. Populations of Artemia sp. in the studied ponds have a wide range of the optimum zone for the environment salinity. It has been found that the main starting indicator for the beginning of the winter pause in the life of the population is the water temperature (8-10°C), while salinity is of lesser importance. There are presented the data on the composition and abundance of other species of invertebrates (Diptera larvae, Coleoptera imagoes, copepods) living in the studied water bodies during the low-water autumn-winter period