HONOLULU (KHON) — An alarming sight Tuesday morning prompted a shark warning at a Hawaii beach.

Those near busy Ala Moana Beach Park, including master diver Nicholas Back, spotted a shark eating a turtle.

The shark, an estimated seven to eight feet in length, was seen at the surf break known as Courts.

“We were out here at work and we saw a few boats congregated out here outside of Magic Island lagoon,” Back told Nexstar’s KHON. “We also saw some splashing and what looked like unfortunately a little honu (a Hawaiian green sea turtle) was turning into a midday snack for that shark.”

Warning signs have since been posted at the beach.

“That’s a tiger shark eating a turtle and I don’t know if the turtle was dead beforehand or if the shark predated on it, but that’s nature taking place,” Dr. Andrew Rossiter, Waikiki Aquarium Director, explained after seeing a video from the scene.

Honolulu city officials said multiple sharks were also seen swimming off Waikiki Beach.

There was another shark sighting on Monday off Makaha Beach. October is dubbed Shark-tober due to increased tiger shark sightings, but experts said, there’s an even higher uptick this year.

“That’s because the big pregnant females from the northwestern Hawaiian islands, about a third of the population, migrate down here at this time of year to give birth,” Dr. Rossiter said.

According to Honolulu Ocean Safety, there have been over a dozen shark sightings in October alone. The state said it has completed its investigation of six shark bite incidents this year so far.

Experts said there are specific times and places people should stay out of the water to avoid shark encounters.

“One of those places would be at the mouth river runoffs, especially after rain, because sharks will be there, especially, looking for food. Secondly, try to stay out of the water very, very early morning and late, late afternoon when the sun has gone down and it’s almost dark,” said Dr. Rossiter.

If you encounter a shark, experts say to stay calm, cover any shiny accessories, and push the shark’s nose away. Dr. Rossiter adds it’s hard to predict if the winter months will see the same amount of shark sightings as October.