Anthropogenic influence of the fresh water controlled discharge from the White Sea hydropower-stations on shallow-water invertebrates

Research results of the 14-year observations pertaining fluctuations in numerical strength and biomass of intertidal mussel Mytilus edulis L. and some other invertebrates in the upper Kandalaksha Bay are presented. These oscillations are associated with a number of anthropogenic factors; the most important of them are freshwater surface layers of the sea water, which wash the habitats of shallow invertebrates. The freshwater layers of the sea water appear due to the seasonal salvo dumping of fresh water from the reservoir lake Imandra. This process must be corrected in order to minimize its negative impact on the marine ecosystem. Shallow-water ecosystems are food pastures of numerous seabirds, fish, and some species of marine mammals in the region of Kandalaksha and Onega bays. These regions are included into the list of wetlands of international importance for the protection of waterfowl by the Ramsar Convention. We formulated recommendations for the timing and mode of single massive discharge of fresh water from HPP reservoirs into the waters of the White Sea. The need to preserve natural environment and to protect ecosystems (as well as all surrounding biota shallow water areas) that are in the zone of the fresh water discharge influence is considered.