UPDATE: On Friday, July 5, South Padre Island spokesperson Nikki Soto released more details on the four individuals who were treated following Thursday's shark attacks.

Previous story below:

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Authorities from multiple agencies were following the South Padre Island shoreline on Thursday, warning the public to stay out after four incidents of a shark attack were reported.

Only two people were actually bitten, one was grazed and received minor injuries, while a man fought off the shark and received stitches, according to Texas Parks and Wildlife Department Game Warden Captain Chris Dowdy.

READ MORE: Authorities investigating cases of individual shark attacks at South Padre Island

Channel 5 News spoke with experts in the area, who said the number of shark attacks in one day is unprecedented, but it lines up with the way sharks hunt in shallow water.

“This is very unusual,” Texas State Aquarium President and CEO Jesse Gilbert said. “I've been in Texas almost 21 years, and I can count on one hand the number of times we've talked about shark bites —certainly along the coastal bend and the Texas coast. So to have four in one day is dramatic."

Gilbert says a lot of shark behavior in shallow water is hunting for prey like fish and stingrays. Gilbert says the sharks will investigate what’s in front of them with their jaws.

RELATED STORY: Family of South Padre Island shark attack victim speaks out

"The shark runs across something, it's inquisitive as to whether it's something it can eat, and it tastes it tests it and decides it's not going to,” Gilbert said. “Humans aren't on the menu for sharks. Sometimes you’ll hear that there are bites like we've heard today, but the sharks really aren't ingesting what they bite. It’s more of, they're kind of tasting and letting go.”

Watch the video above for reactions to the shark attacks from experts at South Padre Island.

“Unfortunately, that can be very substantial from an injury standpoint,” Gilbert said. “They're not out looking for humans, we are just in their space and they are hunting, and sometimes we have these interactions that aren't positive interactions. But really, the sharks aren't looking for humans."

Cameron County Coastal Extension Agent Tony Resinger says he can think of just four shark attacks in his 42-year career at the island.

Attempts to contain the shark ended at around 3 p.m. Thursday, when the shark escaped to open waters after authorities followed the shark along the coastline. 

RELATED STORY: Channel 5 News ride along as Texas Game Wardens move shark out of shallow water

Resigner said it appears the shark was between the beach line and the first or second sandbar.

“That’s kind of unusual,” Resigner said.

A recent Texas State Aquarium survey found that the Texas coastline has a high shark population.

Watch the video above for the full story.