HispanicBusiness

The shark that on Saturday closed Nauset Beach might filter plankton, rather than devour meat, with its mighty jaws.

Biologist Greg Skomal of the state Division of Marine Fisheries said the shark that trailed kayaker Walter Szulc Jr. of New Hampshire off the Orleans beach was probably not a great white, as previously identified.

"I think it was a basking shark," Skomal said from his cellphone off Monomoy Island and South Beach in Chatham, where he has spent this week observing and trying to tag great whites.

He has seen several of the feared great whites and put an acoustic tag on one Monday, he said.

But he doesn't think the one that came close to Szulc about 50 yards from shore Saturday was one of them.

He said he's judging from a photo and the descriptions from witnesses, including two seasonal employees of the Orleans harbormaster's office, who had thought it was a great white.

The employees huddled with Orleans Harbormaster Dawson Farber when they returned from observing the shark Saturday and looked at many photos of sharks before they made their call that it was a great white, Farber said.

"Who knows if what my guys saw was the same shark in the photograph because there were no kayakers there when they got there," Farber said.

"But Greg Skomal has far more expertise than anyone in the East Coast, so I defer to him," he said.

The fin shape of the basking shark, Skomal said, is more tapered and rounded at the top than the sharper point of a great white's fin. And the behavior of this fish, which lingered on the ocean's surface, doesn't match a great white's style.

"All the great whites we've seen in this area are associated with the bottom," Skomal said. "Basking sharks are quite the opposite."

Most great whites are seen far beneath the surface by spotter planes.

But one witness, a paddleboarder who saw the fin and the tail while he was in the water Saturday near Szulc, still wonders.

"I saw the shark turn and follow the kayak," said Tim Knauer, a social worker from Swampscott. "And I don't know if a shark looking for plankton would be interested in following a kayak."

No matter what, Knauer said his close call with the shark is something he'll be able to tell his grandchildren.

And, Skomal said, the Orleans harbormaster was correct in closing the beach.

"If you're not sure -- and even I'm not 100 percent sure -- it's better to err on the side of caution," Skomal said.

He is asking anyone else who has photos from that day to send them to him through the state Division of Marine Fisheries.

The photos he has seen are a bit fuzzy, he said.

Great whites differ from basking sharks not just in fin shape and food choice.

The basking sharks are larger; in fact, they are the second biggest fish in the ocean.

Anything more than 20 feet is going to be a basking shark, Skomal told the Times in 2010. Great white sharks here don't get much more than 18 or 19 feet long, he said.

No beaches have been closed since Saturday, according to officials in Orleans and Chatham.

But great whites are definitely out there.

"We have shark sightings daily," Chatham Harbormaster Stuart Smith said.

The state Division of Marine Fisheries this week has been observing and monitoring the shark situation near Monomoy Island, where thousands of seals congregate. Seals are a favorite food of sharks, and their presence has made shark sightings an increasingly common occurrence in Chatham and along the outer beaches of Cape Cod.

"We're trying to understand more about the sharks' behavior and patterns," Smith said, adding people need to learn to share the water with them.

On June 30, the town of Chatham issued an advisory telling swimmers to stay 300 feet away from seals, and that advisory remains in effect, Dan Tobin, Chatham's director of parks and recreation, said.

There has not been a shark attack on a human in local waters since 1936, when a man was killed swimming in Buzzards Bay near Mattapoisett.