Locals in the Ria Formosa area were astonished earlier this week when several dolphins were spotted swimming in the river. Zoomarine biologist, Élio Vicente, revealed that although the water is considered to be contaminated and full of potentially harmful objects, the dolphins were in no danger. “Dolphins have an acoustic navigation system and can swim in polluted waters without catching diseases,” he explained. Officers from the Maritime Police made sure the visitors came to no harm and carefully watched every move the mammals made until they departed. “The dolphins came here looking for food. This is becoming more common in this area,” Vicent explained.