A pod of dolphins was rescued by a Nova Scotia fire department Thursday.

The five Atlantic white-sided dolphins had swum up the Cornwallis River near Port Williams before running into trouble. The marine mammals were poised to be stranded as the tide ebbed.

The Port Williams fire department stepped in to help.

Crews took out boats to guide the dolphins along the river. The firefighters were able to herd them back to the safety of deep water.

Marine Animal Response Society Coordinator Andrew Reid said the 2.5 metre, 200 kilogram dolphins needed rescuing before the lowering tide beached them.

Dolphins and porpoises enter the rivers around the Minas Basin after chasing schools of herring and pollock. Dolphins have sonar and can detect water depth, but get confused when swimming in salt marshes and mud flats.

Reid said that's what happened to the pod Thursday afternoon.