Includes maps of the spatial distribution of temperature, salinity, oxygen, percent oxygen saturation, phosphate, nitrate, ammonium nitrogen, silicate, organic nitrogen and phosphorus constructed using data from complex ecosystem studies by VNIRO and TINRO during the 1989-1997 period are presented. All maps were constructed for July-August because all expeditions were conducted during this period. Hydrochemical maps were constructed for horizons (standard depth levels) of 0, 20, 50, 75, and 100 mto cover the entire euphotic layer. It also includes the vertical distribution of salinity, oxygen, phosphate, silicate, nitrate, ammonium nitrogen, organic phosphorus and organic nitrogen at seven sections crossing the main structures of the Sea of Okhotsk. Concentrations of all nutrients are expressed in micromoles (æM). Such a form of expression facilitates a comparison of nitrogen, phosphorus, and silica stocks in the euphotic layer and solution of the problem on the limitation of primary production within the frameworks of Redfield-Richards₂ model. The most important result of this work is associated with the identification of quasi-stationary eddy structures and illustration of their role in formation of bioproductivity of the Sea of Okhotsk.