Phytoplankton and Hydrochemical Parameters Near Net Pens with Beluga Whales in a Shallow Bay of the Northwestern Sea of Japan

The dynamics of phytoplankton composition and main hydrochemical parameters have been studied in Paris Bay, northwestern Sea of Japan. This body of water draws particular attention due to the captive beluga whales, Delphinapterus leucas , which are kept in open net pens here. According to the results of investigations conducted, the main factors that influence the hydrochemical parameters in this area are the water exchange, terrestrial runoff, ice melting, and phytoplankton blooms. Phytoplankton has the most pronounced effect in early spring, when its destruction is accompanied by a significant increase in concentration of dissolved nutrients, and in early summer, when proliferation of diatoms causes a depletion of nutrients. An analysis of the hydrochemical parameters and phytoplankton composition has shown that the marine mammals kept in captivity exert no impact on trophicity of the waters in Paris Bay. The dynamics of abundance of micro-algae are characterized by two or three peaks a year; the pattern of these dynamics is typical of most shallow bays in the northwestern Sea of Japan. Diatom species of the genus Skeletonema ( S. dohrnii and S. japonicum ), which are new to the marine waters of Russia, have been found for the first time.