Diel Vertical Migrations of Hydrobionts in the Coastal Area of Lake Baikal

Abstract

The nocturnal migratory complex (NMC) is formed in the coastal pelagic zone of seas and large lakes (including Lake Baikal) due to the diurnal vertical migrations of benthic animals and their mixing with pelagic hydrobionts. Studies of the structure and abundance of the NMC are performed using plankton nets and video surveillance in several areas of Lake Baikal different in abiotic conditions (water temperature, hydrodynamic state, and underwater landscapes) and thus characterized by the local specificity. When NMCs were observed with artificial lighting, the number of amphipods in the frame increased during the first several minutes and then usually slightly decreased. The expediency of applying underwater video observations of NMCs in environmental monitoring is recognized and appropriate guidelines are given.