Humpback whales journey to the Avalon Peninsula to feed on capelin. Humpback whales journey to the Avalon Peninsula to feed on capelin. (NOAA)

Humpback whales are having a "feeding frenzy" on huge schools of capelin that have moved close to St. John's.

Tour boat operator Randy Gulliver of D.J. Charters in St. John's said Monday the whales are putting on a spectacular show since they've travelled to the Avalon Peninsula to feed on the sardine-sized fish.

"They're moving around, showing the tail. [Sunday] night we had whales breaching … the whole whale jumping out of water, putting on a great show for the tourists," said Gulliver. "You got a 50-tonne whale jumping itself out of the water."

The whales are visible near St. John's from Cabot Tower at Signal Hill National Historic Site.

Gulliver said he believes the whales have arrived in the area a bit early this year.

He said the last time he saw humpback whales during the first week of July was seven years ago, and they stayed around for most of the summer.