A man is in serious condition in a Halifax hospital Thursday night after a swimming accident at Chocolate Lake.

Halifax Firefighters were called to Chocolate Lake just after 5 p.m. to assist emergency health services with a call for a cardiac arrest.     

A man was diving and swimming in the lake off Herring Cove Road when he did not surface.     

Lifeguards who had gone off duty several minutes before, pulled him out of the water.

They administered CPR at the scene until paramedics arrived.

Jen Nagle, an aquatics specialist with Halifax Regional Recreation and Culture, said there a few things people can do to stay safe.

"Swim when lifeguards are on duty. Our lifeguards had just gone off duty when this happened so it might have been able to be prevented," she said.

"Swim when the lifeguard's on, swim within your limits."

Nagle said this was the first major incident at Chocolate Lake so far this season.