Hypoxia has been annual in the Chinhae Bay from 1980s. Together with red tides hypoxia has resulted in oyster mortality. Water circulation of the Chihae Bay is restricted because of its narrow mouth. Eutrophication, which began in 1970s, has accelerated from 1980s in the inner part of Chinhae Bay due to large inputs of domestic and industrial wastes. Low dissolved oxygen content in Chinhae Bay was first measured in the mid-70s. In addition, many shellfish culture farms have been established in and around the bay. Hypoxia is now (since 1985) an annual event and covers about 54% of the bay. 

Hypoxia in Chinhae Bay usually starts in May, covers the widest area by September, and returns back to normoxic condition by October. It is controlled by temperature and stratification, and to a lesser extent salinity. Summer hypoxia and near anoxic conditions have resulted in annual mass mortality of benthos and altered community structure. The affected communities have partially recovered. The recolonization by benthos takes 1-4 months after the return of normodic conditions.

Hypoxia (and organic pollution) has caused decreases in aquaculture production in Chinhae Bay. The bay is also a spawning and nursery ground for many economically important fish species.