FT. LAUDERDALE (CBSMiami) – Sections of Deerfield Beach are closed to swimmers as dozens and dozens of sharks make their annual migration north just off shore.

“We saw a shark about this big right here on the surface of the water, it was very high on the surface,” said Katie Fisher who was shark watching.

For the last two days, several beaches in Palm Beach County were shutdown after thousands of sharks were spotted swimming close to the shoreline.

The marine predators, mostly blacktip and spinner sharks, have been spotted from Boca Raton to Jupiter since the start of the month.

Lifeguards cleared the beaches in the area and that allowed the sharks to swim close to the shore throughout the day.

“They’re in very close to the shore,” said Capt. Mike Brown of Deerfield Beach Ocean Rescue. “I would say 20 yards off the shore on the sandbar. Where we’re standing on the pier, we’ve been seeing them go by sporadically, about a hundred yards out.”

Visitors to the area were surprised to hear that sharks were lurking in the waters.

“They don’t survive in shall water do they?” asked Josefine Bylund of Sweden.

“They’ve been coming within 20 yards of the coast,” CBS4’s Ted Scouten told Bylund.

“Oy! Yeah, I’m going to stay on the beach,” Bylund responded.

Shark sightings off South Florida are not uncommon this time of year.

Once a shark appears near the shore, a lifeguard will close the beach and keep it closed until half-hour after the last shark is spotted.

If you’re swimming at a South Florida beach, be sure to swim along beaches where lifeguards are present. Also, leave your jewelry on the shore. Scientists say sharks are attracted to silver, along with the colors yellow and gold.

Lifeguards said all the splashing and playing in the water could confuse a shark to the point where they mistake a swimmer for a hearty meal.

“They want an easy meal; so someone splashing around in the water, in their eyes, could be a hurt bird or something injured, which would be an easy meal for them,” said Capt. Brown.