Divers from the Naval Service have coaxed a small school of seven common dolphins back to open water after they swam up the River Lee to Cork city centre.
The five adults and two calves brought city traffic to a standstill yesterday as hundreds of people stopped to watch them surface at Penrose Quay.
Marine biologists from the Whale and Dolphin Group at the department of zoology in NUI Cork and four divers from the Naval base at Haulbowline ushered the school of dolphins into the Lower Harbour.
The dolphins arrived in the harbour on Wednesday night and yesterday moved upriver. Dr Emer Rogan of UCC said common dolphins "rarely come into estuaries like bottle-nose dolphins such as Fungie and they're not used to narrow channels and freshwater."
It did not appear any of them was injured so it was difficult to say why they had come so far upstream, but she said they may have come up in search of mackerel.