On Monday, Ocean research group OCEARCH shared a screenshot of their shark tracker, showing a line of five white sharks (Carcharodon carcharias) seemingly “stacked” next to one another in a line. A sixth was tracked close to the coast east of Jacksonville.

“Check out these white shark pings from the past couple of days/weeks stacked right along the edge of the Gulf Stream,” said OCEARCH. “Positioning themselves here allows them to access a huge range of water temperatures just by moving relatively short distances east and west.”

Sharks appear on the shark tracker when they break the water surface and the monitors they have been equipped with “ping” a signal to OCEARCH’s system.

The tracker shows some movement since the screenshot was shared on March 30, 2020 and the great whites are no longer appearing so neatly “stacked.”

Despite appearances, these sharks were probably not swimming side-by-side at the time the screenshot was taken. The pings were made on different days—the first on March 16, 2020 and the last on March 30, 2020.

At 12 feet 7.5 inches, Jefferson—an adult male named after Jefferson’s Bourbon—is the largest of the six and pinged on March 16, 2020. Helena—an adult female who weighs 1,314 pounds—is the heftiest and pinged on March 30, 2020.

The most recent ping is Ferg, an 11 feet 8 inch male, weighing 874 pounds, who was tracked near Cape Lookout on March 31, 2020 at 13:12 p.m.

Other sharks include Shaw, a 10 feet 3 inch male; Sydney, 12 feet 2 inch male; and Caper, a 8 feet 3 inch female named after the people of Cape Breton who go by the name Capers.

OCEARCH’s images show the sharks positioning themselves near the Gulf Stream, a section of the ocean conveyor belt called the Thermohaline Circulation or Atlantic Meridional Overturning Circulation. The belt stretches right across the world and is steered by differences in temperature and salt concentrations—both of which affect water density.

The Gulf Stream extends from Florida to Canada on North America’s east coast and across the ocean to Europe, bringing warmer waters from the Gulf of Mexico into the Atlantic Ocean.

“Most likely there are oceanographic factors influencing their movement,” Chris Fischer, OCEARCH Expedition Leader and Founding Chairman, told Newsweek.

“Positioning themselves where they are offers access to a wide range of water temperatures just by moving small distances east and west. This could also be an ideal area for sharks because it is right on the edge of the Gulf Stream where the stream’s current stirs up nutrients from the seafloor, making it an area capable of supporting an abundance of life.”

North Carolina is one of four states that lie in the Northwest Atlantic Shared Foraging Area (NASFA); the others being South Carolina, Georgia and Florida.

According to OCEARCH, the region is noted for its body of cooler water between the Gulf Stream and shoreline. As well as providing a range of different water temperatures, it can be a source of abundant prey as many species migrate along this particular route.

“It extends from Cape Hatteras to Cape Canaveral and it is a region we suspect nearly all white sharks in the Northwest Atlantic utilize at some point during the cooler winter months,” said Fischer. “They have been utilizing this area for a long time and the Tracker is now helping us see this.”

The North Carolina coast is a popular hangout for white sharks and other species, including sand tiger sharks and scalloped hammerheads.

According to the North Carolina Coast Watch, great whites tend to stay offshore but have been known to approach the beach. While the species can be found in Carolina coastal waters year-round, they are most commonly spotted in the winter and in early spring.

“We expect these sharks to move north as water temperatures increase. We suspect some will go to Cape Cod while others will go up to Nova Scotia and Newfoundland,” said Fischer.

“The sharks do not follow the Gulf Stream but we suspect it does influence their migrations. In general, we see them stay west of it as they move north.”

This article has been updated to include comments from Chris Fischer.