Qualitative and quantitative characteristics of bacterioplankton and bacteriobenthos in the areas of natural and artificial reproduction of scallop Mizuhopecten yessoensis in Aniva Bay (Sakhalin Island)

Results of microbiological tests of water and bottom sediments conducted at the sites of natural and artificial reproduction of scallop Mizuhopecten yessoensis in the Aniva Bay from May to October 2024 are presented. The total abundance of bacterioplankton at the sea surface ranged in 0.50–2.14.10 6 cells/mL, at the bottom — in 0.80–1.24.10 6 cells/mL, and their biomasses were 37.13–220.42 and 69.99–161.12 mg/m 3 , respectively. These values corresponded to mesotrophic-eutrophic class of water. The abundance of saprotrophic bacteria in the surface layer varied seasonally from 10 2 to 10 5 cells/mL. Such seasonal changes were not registered in the bottom layer and bottom sediments where their abundance varied within the orders of 10 4 –10 5 cells/mL. No species of sanitary and indicative microflora were detected that was a sign of absent anthropogenic influence. Еtiologically significant Vibrio parahaemolyticus bacteria were found in water and bottom sediments which are the pathogens of food poisoning for humans.