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Aim . The continuous monitoring of changes in ecosystems must be carried out in connection with global climate changes that affect the state of water bodies. Remote sensing methods have many advantages as a promising method for monitoring biocenoses in large water bodies. We carried out a comprehensive study comparing the results obtained using the latest instruments and methods to expand their further application to the continuous monitoring of water bodies. Material and Methods . The field research was undertaken using hydroacoustic sensors, submersible holographic camera and high‐resolution thermal sensors in addition to the classical methods of studying the zooplankton ecology – the Juday net and CTD probe. Water temperature, chlorophyll, photosynthetically active radiation and other parameters were measured with an AAQ‐Rinko probe. We provided data for one vertical up to a depth of 100 m. Results . The main components of mesozooplankton during the ice period are different age stages of the endemic crustacean Epischura baikalensis Sars 1900 and several rotifer species. The article discusses the heterogeneity of the environment and the distribution of plankton detected by various instruments. Conclusion . The experimental results obtained with the help of a set of devices show that the distribution of zooplankton is very strongly dependent on the physical parameters of the environment. The use of remote sensing methods is an important step towards the automation of basic monitoring of the ecosystem of Lake Baikal and other water bodies. The obtained field data will make it possible to further improve the pattern recognition algorithm in the software of the holographic installation for the specific conditions of Lake Baikal. The results of the vertical distribution and migrations of zooplankton in connection with environmental parameters are assumed to be processed using mathematical modeling methods.

In October 2018, after the change in the temperature profile and chlorophyll concentration, we recorded the changes in the distribution parameters of mesozooplankton in the surface 100 m layer at the station located in the pelagic zone of Lake Baikal. The study was carried out on horizons of 0-50and 50-100 m. Measurements were performed using an AAQ-Rinko water quality probe (JFE, Japan), a SBE-25 CTD probe (SeaBirdElectronics, USA) and a Furuno FCV-1100 sonar (Furuno, Japan). We found a deepening of zooplankton after the immersion of the chlorophyll and temperature maximum.

The analysis of genetic polymorphism of Epischura chankensis from Lake Khanka, one of the key species of zooplankton, identified traces of geographical subdivision in the past in the current single population, probably owing to the formation of isolated reservoirs in the lake valley during its regression.

The population structure of Epischura baicalensis Sars (Copepoda, Calanoida), one of the key endemic species of the plankton community of Lake Baikal was studied. An analysis of mitochondrial DNA polymorphism revealed no genetic differences between Epischura sampled in the different basins of the lake or in the winter-spring/summer generations. Baikal Epischura is represented by a single panmictic population with a high level of mtDNA haplotype diversity.

A comparative analysis of the habitat characteristics, the gut content, and the elemental composition of the cutting edge of the mandibles is provided for two species of crustaceans (Copepoda, Calanoida), Eurytemora velox (Lilljeborg, 1853) and Eurytemora lacustris (Poppe, 1887). These representatives of the brackish and marine fauna inhabit the Belarusian freshwaters. The paper presents the generalized data on the recent state and changes in the ranges of species. The differences in the silicification of mandibles of species may reflect the different nutrition strategies and habitat selection.

In March 1999 and 2000, we carried out synchronous observations for species representing the entire pelagic food web in lake Baikal: picoplankton, phytoplankton, copepods (Epischura baicalensis), amphipods (Macrohectopus branickii) and sculpin larvae (Comephoridae). During daytime, the layer with the maximal density of Epischura nauplii coincided with the maximal distribution of pico- and phytoplankton in the 0-15 m layer. In this layer, 60-70 % of the nauplii were feeding. The diurnal distribution of Epischura nauplii coincided with that of fish larvae, that feed intensively on Epischura nauplii during daytime, but did not overlap with the second predator, the amphipod Macrohectopus. At night, the decrease of feeding activity and the descent of the maximal distribution of nauplii coincided with the ascent of Macrohectopus to upper layers. We propose, that the Epischura nauplii respond to the threat from the invertebrate predator with anti-predation behaviour (reduced feeding and dispersal/descent), while the threat from fish larvae during day is ignored, probably because of the low of fish larval density.

The population structure of Epischura baicalensis Sars (Copepoda, Calanoida), one of the key endemic species of the plankton community of Lake Baikal was studied. An analysis of mitochondrial DNA polymorphism revealed no genetic differences between Epischura sampled in the different basins of the lake or in the winter-spring/summer generations. Baikal Epischura is represented by a single panmictic population with a high level of mtDNA haplotype diversity.