Shawn Hanson said in a Facebook post that he was preparing to fillet his freshly caught salmon on the beach when the cougar appeared from the woods and snatched his puppy Bailey.
He quickly chased the animal into the woods where he confronted it.
"I grab Bailey... with one hand, punch the cougar in the face with the other, and it releases its grip on her neck," he said.
"I run to the truck and grab the 12 gauge and a box of shells and head back into the bush after this filthy bastard."
He says he shot the cougar three times.
According to conservation officer Brittany Meuller, there had been multiple reports of cougar sightings in the area that week and officers had tried to track down the animal.
A few days later, Mueller received a call from RCMP reporting a man had shot and killed a female cougar after it had taken his dog.
The cougar was reportedly small and in very poor health, but Meuller was not able to confirm that the animal had be punched prior to the shooting.
She says that although it has been a busy cougar season, she does not recommend this type of action be taken due to unpredictable risks.