Here’s a whale of a tale — that happens to be true.

A humpback whale was spotted bopping around Raritan Bay off the coast of Staten Island on Tuesday morning — wowing a group of Staten Island zookeepers who took the day off to go fishing.

“All of us on the boat we were all shocked,” said Alex Carr, 39, who was out celebrating a friend’s birthday with a pack of co-workers from the Staten Island Zoo. “A lot of us were born and raised on Staten Island, and we’ve never seen a whale this close to us before.”

The beast breached about 100 feet from the boat that Carr and his buddies were riding around 8:30 a.m.

“It was the size of a Range Rover truck,” Carr said. “It stood right around us. We didn’t go into his territory, but we watched it for at least 30, 40 minutes.”

Carr believes there were actually two whales, because he kept seeing them surface in different places, but he wasn’t sure because he never saw more than one animal come up at once.

A recent rise in sightings of the massive mammals can be attributed to a cleaner harbor and the resurgence of a feeder-fish species called Menhaden, whale-watchers have said.

“Last time I went fishing was 15 years ago, and I truly see a big difference in the water,” Carr said. “We didn’t see any pollution floating which is unusual in the New York Harbor.”