Some peculiar features of the hydrochemical regime and the fauna of mesohaline waters

The information available reveals pronounced changes in the ion ratio when marine and fresh waters are mixed. The critical salinity has been shown to be about 5%. in the Kara, White, Baltic, Azov, Black and, probably, Caspian Seas, and British Columbia. Corresponding results were obtained in experimental mixings of White Sea waters with a variety of fresh waters. A close connection is suggested between mixed water hydrochemistry and the existence of an eco-physiological barrier. This barrier divides, at salinities of 5 to 8%., the two basic types of aquatic animals into marine and freshwater representatives.