She said: "After such a long period in the water and with nightfall approaching we were gravely concerned."
But hours later, when it appeared certain he had fallen victim to the waves, they dragged him from the water.
Ms Petrie told RTÉ News: "The crew on the Coastguard rescue helicopter were delighted when they located the man still with his surf board and 13 miles off the coast.
"He was kitted out with all the right clothing including a thick neoprene suit and this must have helped him to survive for so long at sea.
"He is hypothermic but conscious and has been flown to hospital in Belfast."
"He did the right thing by staying with his surfboard and that certainly aided his survival."
Mr Bryce, who was believed to be heading to Westport Beach from Campbeltown, was taken to Belfast Hospital to be checked over.
Chief Inspector Paul Robertson said: "The response to our appeal to find Matthew has been outstanding.
"It has been a real team effort and I would like to thank everyone who offered their assistance."