Islamic Interpretation of Dreams (Ibn-i Sirin):
(Pearl fishery; Plunge) Ifone sees himself diving into the ocean for pearls in a dream, it indicates his attachment to worldly treasures.
Ifone sees himself diving into the waters and finds out that he could get nothing out of it except mud in his dream, it means distress caused by someone in authority.
If one brings a pearl out of the water in a dream, it means marriage or acquiring knowledge or discovering a treasure.
Ifone dives into a river and finds it difficult to come out of the waters in the dream, it means that he will suffer from burdens he cannot carry, or bear patience with adversities. Diving into the ocean to extract pearls from oysters in a dream also means seeking knowledge or wealth.
(Also see Pearl diver)