A bikini-clad woman floating on a surfboard on Halloween a quarter-mile from Seabright Beach found herself amongst a group of kayakers, all whom witnessed close-up two humpback whales feeding on anchovies and plankton near Santa Cruz, Calif.

Barb Roettger, a Santa Cruz massage therapist and ocean enthusiast, had her camera rolling and captured the two whales feasting near the unsuspecting witnesses. The video has since gone viral after its posting on YouTube and streaming on Good Morning America, NBC, CBS and other news organizations.

A group of half a dozen humpback whales has been feeding off the Santa Cruz coast due to a large population of anchovies in the water late in the season. The whales often feed in frenzies, called lunge feeding, where they will herd anchovies into an area and then shoot straight out of the water with their mouths open to catch as many fish as they can, as is seen in the video.

In recent months, the humpbacks have been feeding unusually close to the coast, which can be dangerous for humans, boats and the whales. Whale watchers are putting themselves at risk by paddling, sailing and floating out to the whale infested waters, reported the L.A. Times. Kayaks have reportedly been flipped over and a sailboat's mast was recently snapped.

Researchers with the National Oceanic and Atmospheric Administration say whale watchers are in danger of being struck by a humpback's 40-ton body and its powerful fins and flukes. The whales can grow larger than a bus and move almost as fast.

If you're right above them, you're likely to get nailed pretty hard, said Scott Kathey, federal regulatory coordinator for the Monterey Bay National Marine Sanctuary, told the L.A. Times.

The marine sanctuary advises whale watchers to remain at least 100 yards away from feeding areas, but as is seen in Roettger's video, it can be difficult to tell where the whales might surface. Roettger told MercuryNews that she saw the tell-tale bubbling and knew the whales were coming, but by that time it was too late to move.

Despite the close encounter, Roettger told MecuryNews that the video is actually funny. The man sitting on the kayak was busy looking at the girl in the bikini when the whales surfaced, she said, and missed much of the show.

The husband on that kayak was just eyes on the prize, she said. He missed the whole thing.

Surfer Almost Swallowed by Humpback Whale Video: