This data set was collected at roughly 7-10 day intervals approximately 1 km offshore from Bolshie Koty on Lake Baikal. Depths span 0 - 250 m with regularity and frequently deeper. Zooplankton and phytoplankton are identified to species and lifestage where applicable. Temperature and Secchi depth are available for full time series, chlorophyll a and primary productivity are available since 1979. The data set has been under the direction of Mikhail Kozhov, Olga Kozhova and Lyubov Izmest'eva since roughly 1945. Eugene Silow stewards the data.