The Maritime Police went to the scene following a tip, identifying suspicious movements in the farms, in the Ria Formosa.
When the authorities arrived, the perpetrators of the theft fled, abandoning the oysters that were later found inside a boat on the island of Armona.
The oysters were delivered to the oyster farms, who filed a complaint this morning.
The Olhão Maritime Police Local Command took charge of the incident and is continuing the investigation to identify those responsible for the theft.