The researchers studied the salinity levels in Jiaozhou Bay in May and October of 1979. They found that the bottom layer of the bay had relatively high salinity levels in both months. In May, there was a low salinity area at the bottom of the bay mouth, while in October, the salinity was lower outside the bay mouth. The salinity levels inside the bay mouth were higher than outside. Overall, the salinity in Jiaozhou Bay was high, with a small change in salinity from outside to inside the bay mouth.