A LUCKY group of whale watchers got more than they bargained for yesterday when a whale gave birth right in front of them.

Passengers on board the Sea World Whale Watch boat witnessed the newborn humpback take its first breathe when it was born just off the Seaway about 10.30am.

Sea World Whale Watch general manager David Robertson said three whales were spotted behaving strangely.

media_camera The first pictures of the newborn calf

“They were going in circles which is a bit strange then suddenly this little calf appeared,” he said.

“(It) was smaller than its mothers head ... only about one metre long.”

Mr Robertson said it was a special moment that celebrated the reason humpback whales make their annual migration.

“The majority of babies are born up near the Great Barrier Reef because the water is calmer and warmer but I’m guessing what occurred in this case is the whale miscalculated,” he said.

“It was a choppy day out on the Seaway but the calf was doing well.”